Table of Contents Author Guidelines Submit a Manuscript
Journal of Nanomaterials
Volume 2019, Article ID 1562130, 17 pages
https://doi.org/10.1155/2019/1562130
Review Article

Recent Developments in Nanostructured Palladium and Other Metal Catalysts for Organic Transformation

1Center for Integrative Petroleum Research, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia
2Center of Research Excellence in Renewable Energy (CoRERE), King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia

Correspondence should be addressed to Muhammad Shahzad Kamal; as.ude.mpufk@kilamdazhahs

Received 16 April 2019; Revised 25 August 2019; Accepted 12 September 2019; Published 20 October 2019

Guest Editor: Sally El Ashery

Copyright © 2019 S. M. Shakil Hussain et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Nanocatalysis is an emerging field of research and is applicable to nearly all kinds of catalytic organic conversions. Nanotechnology is playing an important role in both industrial applications and academic research. The catalytic activities become pronounced as the size of the catalyst reduces and the surface area-to-volume ratio increases which ultimately enhance the activity and selectivity of nanocatalysts. Similarly, the morphology of the particles also has a great impact on the activity and selectivity of nanocatalysts. Moreover, the electronic properties and geometric structure of nanocatalysts can be affected by polar and nonpolar solvents. Various forms of nanocatalysts have been reported including supported nanocatalysts, Schiff-based nanocatalysts, graphene-based nanocatalysts, thin-film nanocatalysts, mixed metal oxide nanocatalysts, magnetic nanocatalysts, and core-shell nanocatalysts. Among a variety of different rare earth and transition metals, palladium-based nanocatalysts have been extensively studied both in academia and in the industry because of their applications such as in carbon-carbon cross-coupling reactions, carbon-carbon homocoupling reactions, carbon-heteroatom cross-coupling reactions, and C-H activation, hydrogenation, esterification, oxidation, and reduction. The current review highlights the recent developments in the synthesis of palladium and some other metal nanocatalysts and their potential applications in various organic reactions.

1. Introduction

After realizing the unique morphological, structural, and optoelectrical characteristics of nanomaterials, their wide range of applications has been explored in various fields [1]. These include environmental, energy harnessing, biomedical sector, and catalysis [27]. The chemical process that involves the use of nanomaterials as a catalyst can be termed as nanocatalysis, while the nanomaterial can be termed as nanocatalyst. Based on their morphologies, nanocatalysts can be classified into zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) structures [8]. The control dimensions of these materials induced specific physicochemical characteristics, which make them special for the catalysis industry [9]. More recently, researchers show significant inclination to use nanocatalysts in advance heterogeneous and homogenous catalysis applications [10]. A number of reviews in the area gave an insightful view into the prospects of nanostructured catalysis [1114]. The catalyst system composed of nanoparticles/nanocomposites showed greater catalytic activity and selectivity because of its morphology and nanodimensional characteristics. Though many materials have been utilized as nanocatalysts in industries, transition metal NPs have received significant attention due to their unique physicochemical characteristics, abundant availability, and more importantly, consumer-friendly costs. It is well established that the size, morphology, and solvents play a key role in the catalytic activity, selectivity, and stability of the nanocatalysts [15].

The present review is an attempt to realize the current development and prospects in nanostructured catalysts, especially for organic synthesis. The beginning portion of the review is dedicated to the effect of various factors on the overall performance of nanocatalysts. This is followed by a critical overview of organic transformations, with a few case studies on Pd, Pt, Fe, Cu, Ag, Au, and Zn NPs, as well as other examples. In the later part of the review, some insights are provided through the Conclusion along with a few future recommendations about the future potential of nanostructured catalysts.

2. Factors Affecting the Performance of Nanocatalysts

There are several factors that affect the performance of nanocatalysts. However, this section will mainly focus on three important factors which include particle size, particle shape, and solvent.

2.1. Particle Size Effect of Nanocatalysts

Over the past few years, significant research has been conducted to identify the effect of nanoparticle size on catalytic performance for various chemical transformations [16]. As the particle size decreases, their surface area-to-volume ratio is enhanced, allowing more atoms on the surface to take part in the reaction [17]. As a result, improved catalyst activity and selectivity can be achieved. The particle size is very important for the development of highly active and selective catalysts as well as for the reduction of catalyst loading. Yoo et al. found better electrocatalytic and electronic properties by decreasing the size of Pt/TiO2 nanocatalysts [18]. Bond and Thompson discovered that the catalytic activity of gold nanoparticles depends on their size, support system, and synthesis methods [19]. The gold catalyst is composed of very small-sized particles (<5 nm) and is supported by TiO2. Before such discovery, gold was assumed to be the least catalytically active metal. Li et al. synthesized palladium nanoparticle-graphene hybrids and investigated the catalytic activities of such Pd-graphene hybrids in Suzuki reaction under aerobic and aqueous conditions [20]. It was observed that a palladium-graphene hybrid with a 4 nm particle size of palladium gave a 100% yield along with 95.5% selectivity. However, a palladium-graphene hybrid with a 15 nm particle size of palladium gave a 93.7 yield along with 95.2% selectivity.

2.2. Particle Shape Effect of Nanocatalysts

The shaped-controlled synthesis of catalytic materials is widely regarded to control some important physicochemical properties of nanocatalysts [21]. Many reports are available in the literature in this regard. For instance, hemispherical gold nanoparticles gave better results as compared to spherical-shaped gold nanoparticles for the oxidation of carbon monoxide (CO) even at low temperature [22]. In 2005, Henry reported a brief review with practical examples regarding the effect of nanoparticle shape on their properties in numerous developing technologies [23]. Narayanan and El-Sayed synthesized tetrahedral- and cubic-shaped platinum nanoparticles and studied the relationship of shape reactivity [24]. Shape control is significantly reported for photocatalytic applications in the literature. Khan and Qurashi synthesized highly controlled platelet-shaped copper vanadate nanocatalysts for PEC water splitting and compared the results with NPs of conventional shape. It was determined that the shape-controlled copper vanadate enhanced the light trapping properties of the catalyst and hence enhanced the photoelectrochemical performance of the catalyst [25].

Similarly, shape-controlled NPs are also found useful in organic conversion to some extent. As reported by Luo et al., shape-controlled synthesis of Rh-based nanocrystals and supported Rh-based nanocatalysts was found efficient in heterogeneous conversions such as in methane conversion and olefin hydroformylation [26].

2.3. Solvent Effect on Nanocatalysts

A solvent has a significant impact on the reaction pathway, reaction energy, and activation energy. The geometric structure and the electronic properties of nanoparticles can be influenced by the interaction of a solvent and metal atoms. Dufour et al. reported the effects of solvents on the electronic and structural properties of small gold clusters [27]. Li and Liu demonstrated the geometrical, electronic, and photocatalytic properties of titania anatase nanoparticles in aqueous media [28]. A comprehensive study of the effects of polar and nonpolar solvents on electronic and geometrical properties of nanocatalysts was conducted by Hou et al., and it was noted that a polar solvent has a great impact on the properties of nanocatalysts. It was observed that the ionization potential decreased by increasing the polarity of the solvent. Therefore, it was easier for neutral species to donate an electron in the solvent. Moreover, the electron-donating ability of a neutral species is considerably increased in a polar solvent as compared to that in a nonpolar solvent [29]. Recently, Chowdhury et al. synthesized palladium nanoparticles in an aqueous dimethyl formamide (DMF) solvent with a changing composition of DMF. Different shapes and geometries of palladium nanoparticles, such as hexagonal, cuboidal, and triangular plates, were obtained by varying the composition of DMF. It was emphasized that the various geometries of palladium nanoparticles are due to the blocking and interaction of DMF to some planes of nanoparticles leading to different geometries [30].

3. Major Nanocatalysts for Organic Synthesis

A huge number of metals have been investigated for organic transformations, and these metals showed better results in the formation of pharmaceuticals, fine chemicals, and new materials [31]. Among the varieties of different rare earth and transition metals, palladium is one of the most widely used transition metal for carbon-carbon coupling reactions, and palladium-based nanocatalysts have been extensively studied both in academia and in industry because of their applications such as in sensors, fuel cell catalysts, hydrogen storage, dechlorination, and organic transformations. Therefore, we mainly focused on the current development of palladium-based nanocatalysts for cross-coupling reactions. However, some other metals which have been successfully applied in this field have also been highlighted.

3.1. Palladium-Based Nanocatalyst
3.1.1. Palladium-Based Nanocatalysts for Carbon-Carbon Cross-Coupling Reactions

Palladium-assisted nanocatalysts for carbon-carbon bond formation including Suzuki [32], Heck [33], Sonogashira [34], Negishi [35], Stille [36], Kumada [37], and Hiyama [38] cross-coupling reactions (Scheme 1) have made a huge impact on organic reactions because of mild reaction conditions and tolerance to various functional groups [39]. Such kinds of reactions showed extensive applications in the formation of pharmaceuticals, agrochemicals, and other important industrial products [40].

Scheme 1: Palladium-based nanocatalysts for carbon-carbon cross-coupling reactions.

Among the various carbon-carbon coupling reactions, Suzuki, Heck, and Sonogashira reactions are the most important reactions and play a central role in the formation of natural products, pharmaceutical, and agrochemicals [41]. Table 1 lists the various metal nanoparticles for catalyzing Suzuki, Heck, and Sonogashira cross-coupling reactions.

Table 1: Palladium-based nanocatalysts for carbon-carbon coupling reactions.

aIsolated yield. bGC yield. cYield after work-up.

Within the framework of carbon-carbon cross-coupling reactions, the Suzuki reaction is the most extensively used reaction and it has been the benchmark for identifying the catalytic activity of newly prepared metal nanoparticles. In 2008, Kim et al. synthesized bimetallic nanoparticles (Pd-Ag, Pd-Ni, and Pd-Cu) on carbon support through the γ-irradiation technique for Suzuki and Heck cross-coupling reactions [52]. The catalytic efficiency of these supported bimetallic nanoparticles in Suzuki reaction were in the order of based on the reaction yield , respectively.

The various metal nanocatalysts used in the Suzuki reaction are listed in Table 2.

Table 2: Suzuki reaction with various metal nanocatalysts .

aIsolated yield. bGC yield.

3.1.2. Mechanism of Cross-Coupling Reactions

The reactants meet on a palladium atom and become so close together that reaction takes place. The major role of palladium and the other metals is to enable and encourage two coupling partners to undergo a chemical reaction. In 1972, Kumada et al. suggested that the catalytic cycle of a cross-coupling reaction occurs in three steps including oxidative addition, transmetalation, and reductive elimination (Scheme 2) [67].

Scheme 2: The proposed mechanism of cross-coupling reactions.

The reaction mechanism usually begins with the zero-valent palladium (Pdo) which undergoes oxidative addition (step 1) by reacting with an organic electrophile to form a Pd (II) species [68]. Usually, step 1 is the rate-determining step in this three-step catalytic cycle. Subsequently, transmetalation (step 2) occurs in the presence of a base for the transfer of towards a less electropositive metal. In this step, both coupling partners join the same metal center while removing the functional groups. At the end (step 3), reductive elimination occurs which leads to the formation of a new carbon-carbon bond as well as the regeneration of a zero-valent palladium species which is ready for another cycle. An unsaturated organic species was found to undergo a faster coupling reaction by following the order .

3.1.3. Palladium-Based Nanocatalysts for Carbon-Heteroatom Cross-Coupling Reactions

Palladium nanocatalysts have been successfully applied in carbon-heteroatom cross-coupling reactions such as in Buchwald-Hartwig amination. Recently, Panahi et al. reported an immobilized palladium nanocatalyst on a silica-starch substrate (PNP-SSS) as an effective catalyst for carbon-nitrogen cross-coupling reactions through Buchwald-Hartwig amination with excellent catalytic activity and reusability [69] (Scheme 3).

Scheme 3: Buchwald-Hartwig amination using PNP-SSS [69].

Most recently, Hajipour et al. studied the efficiency of a palladium nanocatalyst supported on cysteine-functionalized magnetic nanoparticles for N- and O-arylation reactions in environmentally friendly conditions [70]. The authors claimed that the synthesized palladium catalyst system exhibited excellent recyclability with no substantial deactivation even after ten cycles (Scheme 4).

Scheme 4: N- and O-arylation using a cysteine-supported palladium nanocatalyst.

Similarly, Veisi et al. also reported a carbon-heteroatom cross-coupling reaction using a palladium nanocatalyst immobilized on carbon nanotubes and observed no change in catalytic activity for up to six cycles (Scheme 5) [71].

Scheme 5: C-N cross-coupling reaction using a palladium nanocatalyst immobilized on carbon nanotubes.
3.1.4. Palladium-Based Nanocatalysts for Carbon-Carbon Homocoupling Reactions

The biaryl formation is a very important reaction in the field of catalysis, total synthesis, fine chemicals, and supramolecular chemistry [72]. The bond between two aryl groups is often available in natural products, dyes, medicine, and agrochemicals. The copper-catalyzed homocoupling reaction is a well-known method for the construction of biaryls, but it requires harsh reaction conditions. Movahed et al. reported palladium nanoparticles on nitrogen-doped graphene (Pd-NP-HNG) for an Ullmann-type homocoupling reaction in water (Scheme 6) [48].

Scheme 6: Ullmann homocoupling reaction using Pd-NP-HNG nanocatalysts [48].

Recently, Rafiee et al. reported the synthesis of a palladium nanocatalyst immobilized on a magnetic few-layer graphene support which they applied on cross- and homocoupling reactions [73]. The catalyst system was found to be active up to six runs with no loss of its catalytic activity (Scheme 7).

Scheme 7: Homocoupling reaction of 4-chloro-1-bromo benzene using a Fe2O3@FLG@Pdo catalyst.

Liu et al. prepared a series of polyaniline-supported palladium nanocatalysts for the Ullmann homocoupling reaction of aryl iodides to form biaryls. It was observed that the catalyst activity can be tuned by introducing electron-donating groups (Scheme 8) [74].

Scheme 8: Ullmann homocoupling reaction using a Pd@PANI-H catalyst.
3.1.5. Palladium-Based Nanocatalyst for Hydrogenation Reactions

A palladium catalyst has faster hydrogenation and dehydrogenation processes and are also used in petroleum cracking. A variety of hydrogenation reactions are conducted by palladium nanocatalysts. A palladium nanocatalyst has the capability to combine with a wide range of ligands for highly selective organic reactions. Research is more focused on supported palladium nanoparticles due to their excellent efficiencies and faster rate of reaction. Chang et al. reported on palladium nanoparticles entrapped in aluminum oxyhydroxide for the hydrogenation of nitroaromatics and solid alkenes (Scheme 9) [75].

Scheme 9: Hydrogenation reaction in the presence of (Pd/AlO(OH)) nanocatalysts [75].

The same catalyst (Pd/AlO(OH) was also used by Fry and O’Connor with different concentrations for the hydrogenation of unsaturated esters [76]. The palladium nanoparticles entrapped in aluminum oxyhydroxide were found to be selective without reducing other functionalities in the molecule.

3.1.6. Palladium-Based Nanocatalysts for the Dichromate Reduction Reaction

In 2013, Tu et al. synthesized polyvinylpyrrolidone-stabilized palladium nanoparticles (PVP-Pd) through a chemical reduction protocol for Pd-catalyzed dichromate reduction [77]. Chromium exists in two oxidation states which are (Cr-VI) and (Cr-III) (Scheme 10). Among these two oxidation states, hexavalent chromium (Cr-VI) is a highly toxic and carcinogenic species. However, trivalent chromium (Cr-III) is comparatively nontoxic and even small quantities of (Cr-III) are required by the human body as an essential nutrient. Many reports appeared in the literature on the reduction of (Cr-VI) by using iron nanoparticles, aluminum oxide, titanium oxide, mixed transition metal nanoparticles, palladium nanoparticles, etc. [78]. Yang et al. demonstrated the application of tobacco mosaic virus-templated palladium nanoparticles for the reduction of (Cr-VI) and claimed that such a nanocatalyst system can be applied in different kinds of catalytic reactions [79].

Scheme 10: Reduction of hexavalent chromium (Cr-VI) to trivalent chromium (Cr-III).
3.1.7. Supported Palladium Nanoparticles

Palladium nanoparticles can lose their catalytic activity due to aggregation or precipitation. Therefore, stabilizers such as ligands, polymers, or surfactants are useful to control agglomeration and precipitation [80]. A variety of palladium nanoparticles that have appeared in the literature have described the advantages of supported systems such as carbon nanotubes [81], colloidal support [82], silica [83], metal nanoparticle support [84], polymers [85], carbon [86], and graphene [87]. Palladium nanoparticles supported onto different materials increase the surface-to-volume ratio of the composite and improve the catalytic activity and selectivity of the heterogeneous catalyst. Palladium nanoparticles either in colloidal form or deposited form have been successfully applied as a catalyst for different kinds of reactions. Liew et al. reported a new catalyst system of palladium nanoparticles (XL-HGPd) (Scheme 11) with the help of a cross-linking method [88]. Such a catalyst system was easy to recover and showed excellent recyclability with continuously high catalytic activities.

Scheme 11: Suzuki reaction catalyzed by an XL-HGPd nanocatalyst [88].

Liu et al. prepared palladium nanoparticles (1-5 nm) with the help of a helical backbone containing poly(N,N-dialkylcarbodiimide) (PDHC-Pd) as a polymeric gel for stabilizing a palladium nanocatalyst. Such a composite material was found to be very active for the Suzuki reaction under regular heating or microwave irradiation (Scheme 12) [89].

Scheme 12: Suzuki reaction in the presence of PDHC-Pd nanocatalysts [89].

The catalyst was recycled for the second, third, fourth, and fifth time and reaction yields were 93%, 95%, 92%, and 90%, respectively. Palladium nanocatalysts with carbon nanomaterial support have been successfully applied for glucose oxidation reaction [90]. Glucose is considered as an emerging energy source for fuel cell technology improvement in order to fulfill the green energy requirement.

3.2. Platinum-Based Nanocatalysts

Platinum catalysts have been extensively used in pharmaceutical, chemical, electronic, petrochemical, and fuel cell applications [91]. Such catalysts have shown excellent catalytic and electrical activities as well as corrosion-resistant properties. Platinum-based catalysts have been successfully applied in sensors [92], fuel cells [93], methanol oxidation [94], and petroleum industries [95]. Platinum-based nanomaterials have shown remarkable properties because of their stability in different conditions. Just like other metal nanocatalysts, the activities of platinum-based nanocatalysts also depend on the size and shape of the catalyst. Several methods are available in the literature for the synthesis of platinum nanoparticles such as physical methods [96], solvothermal [97] and hydrothermal [98] approaches, sol-gel [99], and an electrodeposition [100] process. The morphology and properties of a platinum-based nanomaterial such as optical, magnetic, and catalytic properties can be tailored by changing the starting material and reaction parameters [101]. Narayanan and El-Sayed reported the Suzuki reaction between iodobenzene and phenylboronic acid to catalyze using platinum nanocatalysts (Scheme 13) [102].

Scheme 13: Suzuki reaction between iodobenzene and phenylboronic acid catalyze using platinum nanocatalysts [102].
3.3. Iron-Based Nanocatalysts

Iron, as a backbone of infrastructure, received great interest because of excellent magnetic and catalytic properties [103]. Due to their magnetic property, iron-based nanocatalysts can be easily separated by an external magnet after the completion of a reaction [104]. Iron oxide nanoparticles with various structures and morphologies have been widely used for drug delivery [105], biosensor [106], medical [107], and water treatment [108] applications, as well as other applications. Iron oxide nanoparticles have multiple advantages because of their low price and inherent biocompatibility. The synthetic scheme of iron nanoparticles plays a key role in terms of morphologies and chemical and physical properties [109]. Within the framework of different nanoparticles, ferromagnetic iron and cobalt nanoparticles and their oxides and alloys were found to be the most favorable probes for different applications [110].

2,4-Dichlorophenol is a toxic material and is present in both wastewater and soil. Li et al. successfully degraded 2,4-dichlorophenol by either Fenton oxidation or reductive dechlorination with the help of various iron-based nanoparticles [111]. In 2005, Park et al. reported a new synthetic way for the synthesis of monodisperse nanoparticles of iron oxide with a size of 6-13 nm [112]. The synthesis of 6-13 nm particle size was accomplished by the additional growth of the monodisperse nanoparticles of iron oxide. There are several methods available in the literature for the synthesis of iron nanoparticles; however, iron pentacarbonyl decomposition is the most widely used method because of ease of handling and because it only has carbon monoxide as a byproduct. Some other methods are also available in the literature such as the reduction of organic or inorganic salts [113], mechanical methods, and decomposition of other unstable iron compounds [114]. Jagadeesh et al. describe the synthesis of iron oxide-based nanocatalysts for the hydrogenation of nitroarenes to anilines with excellent activity and selectivity (Scheme 14) [115].

Scheme 14: Hydrogenation of nitrobenzene to aniline using iron nanocatalysts [115].
3.4. Copper-Based Nanocatalysts

Copper-based nanocatalysts have received considerable attention because of their high activity and low reaction temperature [116]. The activity of the Cu-based nanocatalyst can be influenced by synthetic protocol, composition, temperature, pressure, concentration, and reactor type [117]. Various methods are available in the literature to synthesize Cu-based nanocatalysts such as hydrothermal [118], coprecipitation [119], homogenous precipitation [120], and impregnation [121]. Recently Lamei et al. reported a green nontoxic catalyst material to comprise nanowires and nanoparticles embedded in a carbonaceous matrix [53]. Such a Cu-based ligand-free nanocatalyst system was applied to the Suzuki coupling reaction with excellent activity and no significant loss of activity observed even after four cycles (Scheme 15).

Scheme 15: Suzuki coupling reaction using different copper catalysts [53].
3.5. Gold-Based Nanocatalysts

Since the pioneering studies of Haruta et al. [122], gold nanocatalysts have become widely used nanoparticles for oxidation [123], reduction [124], hydrogenation [125], homocoupling [126], degradation of organic pollutants [127], and electrochemical sensor applications [128]. In order to expose more atoms on the surface, gold nanoparticles are usually dispersed on a suitable support such as activated carbon [129], starch [130], silica [131], metal oxide [132], and resin [133]. Gold along with magnetic nanoparticles such as catalytic support has gained much attention due to its superparamagnetic properties and environmentally friendly nature. The gold-magnetic nanocatalyst (Au-Fe3O4) has shown excellent catalytic activity in various organic reactions such as oxidation of CO [134] and reduction of H2O2 [135]. Lin and Doong synthesized Au-Fe3O4 nanocatalysts through iron-oleate decomposition in the presence of Au seeds. The catalyst system was successfully applied in the reduction of nitrophenol with excellent activity and selectivity (Scheme 16) [136].

Scheme 16: Reduction of nitrophenol using gold-magnetic nanocatalysts (Au-Fe3O4) [136].
3.6. Silver-Based Nanocatalysts

Silver nanoparticles have been successfully applied in optics, medicine, catalysis, and sensors [137]. Silver-based nanocatalysts are continuously being developed due to their strong absorption in the region of visible light which is easily detectable through a UV-visible spectrophotometer. In terms of organic reactions, silver nanocatalysts are used in reduction reactions [138], alkylation [139], degradation [140], reduction [141], and synthesis of fine chemicals [142]. Recently, Mandi et al. reported the synthesis of supported silver nanocatalysts via acrylic acid polymerization and subsequent immobilization with silver nanoparticles to form nanocomposite Ag-MCP-1. The nanocomposite material was used in a reductive coupling reaction of nitrobenzene with alcohols in the presence of a hydrogen source such as glycerol (Scheme 17) [143].

Scheme 17: Reductive amination reaction between 4-methylnitrobenzene and benzyl alcohol using a Ag-MCP-1 nanocatalyst [143].

Apart from colloidal Ag nanoparticles, 1D and 2D structures of Ag and their composites have also shown huge prospects in catalytic conversion. Ag nanowires and copper oxide-embedded Ag nanowires showed excellent and rapid catalytic activity [144]. The activity and selectivity of such composites were reported to be ecofriendly and distinguished. However, Ag nanowires possessed 40% conversion efficiency along with 95% selectivity, and copper oxide-embedded Ag nanowires showed much higher activity and stability compared to individual metal oxides or metal nanowires [145]. Such demonstration paves way for further efficient designs and innovative applications of metal oxide-embedded 1D and 2D materials as new nanocatalysts for organic conversion.

3.7. Zinc-Based Nanocatalysts

The nanocomposite system containing zinc oxide mixed with other metal oxides has been a material of choice due to several applications such as the production of biodiesel [146], CO2 conversion [147], aldehyde oxidation [148], hydrogen production [118], transesterification [149], wastewater treatment [150], azo dye decoloration [151], and chemoselective acetylation [152]. The activity and selectivity of the zinc oxide-based nanocatalysts rely on size and morphology of the synthesized material. Different methods are available in the literature to describe the synthetic procedures for controlling the size and morphology of the zinc oxide nanocatalysts such as coprecipitation [119], microwave assisted [153], combustion [154], ion exchange, and vapor phase transport [155]. In 2015, Saikia et al. reported the synthesis of zinc oxide nanocatalysts through the leaf extract of Carica papaya and its application in the synthesis of oxime derivatives [156]. The reaction was run without a solvent under microwave irradiation to form an oxime with an excellent yield and with a recycle capability up to 5th run (Scheme 18).

Scheme 18: Conversion of aldehyde/ketone into oximes using zinc oxide nanocatalysts [156].

4. Future Prospects and Challenges

Carbon-carbon cross-coupling protocols such as Suzuki, Heck, and Sonogashira reactions are industrially important reactions, and a review of the literature reveals that these reactions are catalyzed by precious metals including palladium or gold nanoparticles. Therefore, it is highly anticipated that the focus of research will be on the development of either metal-free or nonnoble metal nanocatalysts with high activity and selectivity for carbon-carbon cross-coupling reactions. Nanocatalysts are known to have high activity and selectivity, but they suffer from instability and reusability issues. One way to achieve high stability and reusability is for the nanocatalyst to have a strong interaction with the support system which can prevent an aggregation problem. To achieve this, the support system should have chelating properties to bind the nanoparticles more strongly. Severe conditions such as high-temperature reactions can cause the leaching of metal in the nanocatalysts. Initially, it was thought that the leaching process mainly occurs with nanocatalysts containing the palladium metal. However, in recent times, a number of reports appeared in the literature describing the leaching of other noble metals in nanocatalysts. Therefore, the development of new nanocatalysts that can bear harsh conditions is highly desirable. As depicted earlier, the shape and size of the nanocatalyst have a great impact on their catalytic properties and stabilities. Hence, new methods with a well-controlled size and shape of the nanocatalysts need to be developed. The multistep synthesis using a costly starting material and low yield hinders their commercial applications. Such synthetic protocols need to be replaced with a facile route, a green process, and large-scale production with high quality.

5. Conclusion

In this review, we highlighted the recent progress on the design and development of nanocatalysts and discussed their catalytic application in important organic reactions. The synthetic procedure of nanocatalysts contains various metals such as Pd, Pt, Fe, Cu, Au, Ag, and Zn and have been reviewed along with their important applications. Among the various metals, the palladium-based nanocatalysts are the most widely investigated material for coupling reactions. Palladium nanocatalysts either with a suitable support or as mixed metal oxides are known to increase the surface-to-volume ratio of the composite and improve the catalytic activity and selectivity of the heterogeneous catalyst. The industrially important organic reactions such as carbon-carbon bond coupling reactions, carbon-heteroatom bond coupling reactions, carbon-carbon homocoupling reactions, hydrogenation, reduction, and oxime formation reactions have been reviewed. Similarly, the Suzuki reaction has been a benchmark to explore the catalytic activities of newly synthesized palladium-based nanocatalysts. The future prospects that need to be addressed, on the basis of literature review, have also been highlighted at the end. Consequently, this review article may help on the design and development of new nanocomposite catalysts containing a well-defined shape and size with high activity, selectivity, stability, and reusability. This literature search will also help to identify the best support system for high-performance supported nanocatalysts. Due to the ease of synthesis, high activity, and selectivity, more nanocatalyst systems will be developed in the near future for organic conversion.

Conflicts of Interest

The authors declare that there is no conflict of interest regarding the publication of this paper.

Acknowledgments

The authors are thankful to the Center for Integrative Petroleum Research (CIPR) for the research start-up project SF-17003, the Center of Research Excellence in Renewable Energy (CoRERE), and the Deanship of Scientific Research (DSR) at King Fahd University of Petroleum & Minerals (KFUPM) through project No. IN151003.

References

  1. L. A. Kolahalam, I. K. Viswanath, B. S. Diwakar, B. Govindh, V. Reddy, and Y. L. Murthy, “Review on nanomaterials: synthesis and applications,” Materials Today: Proceedings, 2019. View at Publisher · View at Google Scholar
  2. B. R. Cuenya and F. Behafarid, “Nanocatalysis: size- and shape-dependent chemisorption and catalytic reactivity,” Surface Science Reports, vol. 70, no. 2, pp. 135–187, 2015. View at Publisher · View at Google Scholar · View at Scopus
  3. M. S. Kamal, A. A. Adewunmi, A. S. Sultan, M. F. Al-Hamad, and U. Mehmood, “Recent advances in nanoparticles enhanced oil recovery: rheology, interfacial tension, oil recovery, and wettability alteration,” Journal of Nanomaterials, vol. 2017, Article ID 2473175, 15 pages, 2017. View at Publisher · View at Google Scholar · View at Scopus
  4. L. Li, H. Yang, D. Zhou, and Y. Zhou, “Progress in application of CNTs in lithium-ion batteries,” Journal of Nanomaterials, vol. 2014, Article ID 187891, 8 pages, 2014. View at Publisher · View at Google Scholar · View at Scopus
  5. R. Liu, Q. Zhao, Y. Li, G. Zhang, F. Zhang, and X. Fan, “Graphene supported Pt/Ni nanoparticles as magnetically separable nanocatalysts,” Journal of Nanomaterials, vol. 2013, Article ID 602602, 7 pages, 2013. View at Publisher · View at Google Scholar · View at Scopus
  6. Y. Xu, Y. Liang, L. Jiang, H. Wu, H. Zhao, and D. Xue, “Preparation and magnetic properties of ZnFe2O4 nanotubes,” Journal of Nanomaterials, vol. 2011, Article ID 525967, 5 pages, 2011. View at Publisher · View at Google Scholar · View at Scopus
  7. L. Song, Y. Han, F. Guo et al., “Mesoporous nickel-based zeolite capsule complex with Fe3O4 as electrode for advanced supercapacitor,” Journal of Nanomaterials, vol. 2018, Article ID 9813203, 13 pages, 2018. View at Publisher · View at Google Scholar · View at Scopus
  8. V. V. Pokropivny and V. V. Skorokhod, “New dimensionality classifications of nanostructures,” Physica E: Low-dimensional Systems and Nanostructures, vol. 40, no. 7, pp. 2521–2525, 2008. View at Publisher · View at Google Scholar · View at Scopus
  9. E. González, J. E. Villegas, D. Jaque, E. Navarro, and J. L. Vicent, “Fabrication of 2D, 1D and 0D ordered metallic nanostructures,” Vacuum, vol. 67, no. 3, pp. 693–698, 2002. View at Publisher · View at Google Scholar · View at Scopus
  10. D. Astruc, F. Lu, and J. R. Aranzaes, “Nanoparticles as recyclable catalysts: the frontier between homogeneous and heterogeneous catalysis,” Angewandte Chemie International Edition, vol. 44, no. 48, pp. 7852–7872, 2005. View at Publisher · View at Google Scholar · View at Scopus
  11. A. Makawana, C. B. Sangani, Y.-F. Yao, Y.-T. Duan, P.-C. Lv, and H.-L. Zhu, “Recent developments of metal and metal oxide nanocatalysts in organic synthesis,” Mini Reviews in Medicinal Chemistry, vol. 16, no. 16, pp. 1303–1320, 2016. View at Publisher · View at Google Scholar · View at Scopus
  12. J. Choi and G. C. Fu, “Transition metal-catalyzed alkyl-alkyl bond formation: another dimension in cross-coupling chemistry,” Science, vol. 356, no. 6334, article eaaf7230, 2017. View at Publisher · View at Google Scholar · View at Scopus
  13. N. V. Tzouras, I. K. Stamatopoulos, A. T. Papastavrou, A. A. Liori, and G. C. Vougioukalakis, “Sustainable metal catalysis in CH activation,” Coordination Chemistry Reviews, vol. 343, pp. 25–138, 2017. View at Publisher · View at Google Scholar · View at Scopus
  14. M. M. Lorion, K. Maindan, A. R. Kapdi, and L. Ackermann, “Heteromultimetallic catalysis for sustainable organic syntheses,” Chemical Society Reviews, vol. 46, no. 23, pp. 7399–7420, 2017. View at Publisher · View at Google Scholar · View at Scopus
  15. N. Sharma, H. Ojha, A. Bharadwaj, D. P. Pathak, and R. K. Sharma, “Preparation and catalytic applications of nanomaterials: a review,” RSC Advances, vol. 5, no. 66, pp. 53381–53403, 2015. View at Publisher · View at Google Scholar · View at Scopus
  16. T. P. N. Tran, A. Thakur, D. X. Trinh, A. T. N. Dao, and T. Taniike, “Design of Pd@graphene oxide framework nanocatalyst with improved activity and recyclability in Suzuki-Miyaura cross-coupling reaction,” Applied Catalysis A: General, vol. 549, pp. 60–67, 2017. View at Publisher · View at Google Scholar · View at Scopus
  17. Y.-Y. Yu, Q.-W. Cheng, C. Sha, Y.-X. Chen, S. Naraginti, and Y.-C. Yong, “Size-controlled biosynthesis of FeS nanoparticles for efficient removal of aqueous Cr(VI),” Chemical Engineering Journal, vol. 379, article 122404, 2019. View at Publisher · View at Google Scholar
  18. S. J. Yoo, T.-Y. Jeon, K.-S. Lee, K.-W. Park, and Y.-E. Sung, “Effects of particle size on surface electronic and electrocatalytic properties of Pt/TiO2 nanocatalysts,” Chemical Communications, vol. 46, no. 5, pp. 794–796, 2010. View at Publisher · View at Google Scholar · View at Scopus
  19. G. C. Bond and D. T. Thompson, “Catalysis by gold,” Catalysis Reviews, vol. 41, no. 3-4, pp. 319–388, 1999. View at Google Scholar
  20. Y. Li, X. Fan, J. Qi et al., “Palladium nanoparticle-graphene hybrids as active catalysts for the Suzuki reaction,” Nano Research, vol. 3, no. 6, pp. 429–437, 2010. View at Publisher · View at Google Scholar · View at Scopus
  21. E. Dube and T. Nyokong, “Effect of gold nanoparticle shape on the photophysicochemical properties of sulphur containing metallophthalocyanines,” Journal of Molecular Structure, vol. 1181, pp. 312–320, 2019. View at Publisher · View at Google Scholar · View at Scopus
  22. M. Haruta, “Nanoparticulate gold catalysts for low-temperature CO oxidation,” ChemInform, vol. 35, no. 48, 2004. View at Publisher · View at Google Scholar
  23. C. R. Henry, “Morphology of supported nanoparticles,” Progress in Surface Science, vol. 80, no. 3, pp. 92–116, 2005. View at Publisher · View at Google Scholar · View at Scopus
  24. R. Narayanan and M. A. El-Sayed, “Effect of nanocatalysis in colloidal solution on the tetrahedral and cubic nanoparticle shape: electron-transfer reaction catalyzed by platinum nanoparticles,” The Journal of Physical Chemistry B, vol. 108, no. 18, pp. 5726–5733, 2004. View at Publisher · View at Google Scholar
  25. I. Khan and A. Qurashi, “Shape controlled synthesis of copper vanadate platelet nanostructures, their optical band edges, and solar-driven water splitting properties,” Scientific Reports, vol. 7, no. 1, article 14370, 2017. View at Publisher · View at Google Scholar · View at Scopus
  26. L. Luo, H. Li, Y. Peng, and C. Feng, “Recent advances in Rh-based nanocatalysts for heterogeneous reactions,” ChemNanoMat, vol. 4, 2018. View at Publisher · View at Google Scholar · View at Scopus
  27. F. Dufour, B. Fresch, O. Durupthy, C. Chaneac, and F. Remacle, “Ligand and solvation effects on the structural and electronic properties of small gold clusters,” The Journal of Physical Chemistry C, vol. 118, no. 8, pp. 4362–4376, 2014. View at Publisher · View at Google Scholar · View at Scopus
  28. Y.-F. Li and Z.-P. Liu, “Particle size, shape and activity for photocatalysis on titania anatase nanoparticles in aqueous surroundings,” Journal of the American Chemical Society, vol. 133, no. 39, pp. 15743–15752, 2011. View at Publisher · View at Google Scholar · View at Scopus
  29. M. Hou, Q. Mei, and B. Han, “Solvent effects on geometrical structures and electronic properties of metal Au, Ag, and Cu nanoparticles of different sizes,” Journal of Colloid and Interface Science, vol. 449, pp. 488–493, 2015. View at Publisher · View at Google Scholar · View at Scopus
  30. S. R. Chowdhury, P. S. Roy, and S. K. Bhattacharya, “Room temperature synthesis of polyvinyl alcohol stabilized palladium nanoparticles: solvent effect on shape and electro-catalytic activity,” Nano-Structures & Nano-Objects, vol. 14, pp. 11–18, 2018. View at Publisher · View at Google Scholar · View at Scopus
  31. Y. Zhu and N. S. Hosmane, “Nanocatalysis: recent advances and applications in boron chemistry,” Coordination Chemistry Reviews, vol. 293–294, pp. 357–367, 2015. View at Publisher · View at Google Scholar · View at Scopus
  32. A. Y. Khormi, T. A. Farghaly, and M. R. Shaaban, “Pyrimidyl formamidine palladium(II) complex as a nanocatalyst for aqueous Suzuki-Miyaura coupling,” Heliyon, vol. 5, no. 3, article e01367, 2019. View at Publisher · View at Google Scholar · View at Scopus
  33. E. Rafiee, M. Joshaghani, and P. G.-S. Abadi, “Effect of a weak magnetic field on the Mizoroki-Heck coupling reaction in the presence of wicker-like palladium-poly(N-vinylpyrrolidone)-iron nanocatalyst,” Journal of Magnetism and Magnetic Materials, vol. 408, pp. 107–115, 2016. View at Publisher · View at Google Scholar · View at Scopus
  34. S. Rohani, G. M. Ziarani, A. Ziarati, and A. Badiei, “Designer 3D CoAl-layered double hydroxide@N, S doped graphene hollow architecture decorated with Pd nanoparticles for Sonogashira couplings,” Applied Surface Science, vol. 496, article 143599, 2019. View at Publisher · View at Google Scholar
  35. A. Balanta, C. Godard, and C. Claver, “Pd nanoparticles for C-C coupling reactions,” Chemical Society Reviews, vol. 40, no. 10, pp. 4973–4985, 2011. View at Publisher · View at Google Scholar · View at Scopus
  36. T. Tamoradi, A. Ghorbani-Choghamarani, and M. Ghadermazi, “Synthesis of a new Pd(0)-complex supported on magnetic nanoparticles and study of its catalytic activity for Suzuki and Stille reactions and synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives,” Polyhedron, vol. 145, pp. 120–130, 2018. View at Publisher · View at Google Scholar · View at Scopus
  37. D. Astruc, “Palladium nanoparticles as efficient green homogeneous and heterogeneous carbon-carbon coupling precatalysts: a unifying view,” Inorganic Chemistry, vol. 46, no. 6, pp. 1884–1894, 2007. View at Publisher · View at Google Scholar · View at Scopus
  38. A. R. Hajipour and P. Abolfathi, “Nickel embedded on triazole-modified magnetic nanoparticles: a novel and sustainable heterogeneous catalyst for Hiyama reaction in fluoride-free condition,” Catalysis Communications, vol. 103, pp. 92–95, 2018. View at Publisher · View at Google Scholar · View at Scopus
  39. A. Trzeciak and A. Augustyniak, “The role of palladium nanoparticles in catalytic C-C cross-coupling reactions,” Coordination Chemistry Reviews, vol. 384, pp. 1–20, 2019. View at Publisher · View at Google Scholar · View at Scopus
  40. M. J. Mphahlele and M. M. Maluleka, “Advances in metal-catalyzed cross-coupling reactions of halogenated quinazolinones and their quinazoline derivatives,” Molecules, vol. 19, no. 11, pp. 17435–17463, 2014. View at Publisher · View at Google Scholar · View at Scopus
  41. D. Ganapathy and G. Sekar, “Palladium nanoparticles stabilized by metal-carbon covalent bond: an efficient and reusable nanocatalyst in cross-coupling reactions,” Catalysis Communications, vol. 39, pp. 50–54, 2013. View at Publisher · View at Google Scholar · View at Scopus
  42. A. Ghorbani-Choghamarani, B. Tahmasbi, N. Noori, and S. Faryadi, “Pd-S-methylisothiourea supported on magnetic nanoparticles as an efficient and reusable nanocatalyst for Heck and Suzuki reactions,” Comptes Rendus Chimie, vol. 20, no. 2, pp. 132–139, 2017. View at Publisher · View at Google Scholar · View at Scopus
  43. A. Naghipour and A. Fakhri, “Heterogeneous Fe3O4@chitosan-Schiff base Pd nanocatalyst: fabrication, characterization and application as highly efficient and magnetically-recoverable catalyst for Suzuki-Miyaura and Heck-Mizoroki C-C coupling reactions,” Catalysis Communications, vol. 73, pp. 39–45, 2016. View at Publisher · View at Google Scholar · View at Scopus
  44. P. Veerakumar, M. Velayudham, K.-L. Lu, and S. Rajagopal, “Silica-supported PEI capped nanopalladium as potential catalyst in Suzuki, Heck and Sonogashira coupling reactions,” Applied Catalysis A: General, vol. 455, pp. 247–260, 2013. View at Publisher · View at Google Scholar · View at Scopus
  45. M. Panchal, A. Kongor, V. Mehta, M. Vora, K. Bhatt, and V. Jain, “Heck-type olefination and Suzuki coupling reactions using highly efficient oxacalix[4]arene wrapped nanopalladium catalyst,” Journal of Saudi Chemical Society, vol. 22, no. 5, pp. 558–568, 2017. View at Publisher · View at Google Scholar · View at Scopus
  46. M. Nasrollahzadeh and A. Banaei, “Hybrid Au/Pd nanoparticles as reusable catalysts for Heck coupling reactions in water under aerobic conditions,” Tetrahedron Letters, vol. 56, no. 3, pp. 500–503, 2015. View at Publisher · View at Google Scholar · View at Scopus
  47. F. Heidari, M. Hekmati, and H. Veisi, “Magnetically separable and recyclable Fe3O4@SiO2/isoniazide/Pd nanocatalyst for highly efficient synthesis of biaryls by Suzuki coupling reactions,” Journal of Colloid and Interface Science, vol. 501, pp. 175–184, 2017. View at Publisher · View at Google Scholar · View at Scopus
  48. S. K. Movahed, M. Dabiri, and A. Bazgir, “Palladium nanoparticle decorated high nitrogen-doped graphene with high catalytic activity for Suzuki-Miyaura and Ullmann-type coupling reactions in aqueous media,” Applied Catalysis A: General, vol. 488, Supplement C, pp. 265–274, 2014. View at Publisher · View at Google Scholar
  49. A. Shaabani and M. Mahyari, “PdCo bimetallic nanoparticles supported on PPI-grafted graphene as an efficient catalyst for Sonogashira reactions,” Journal of Materials Chemistry A, vol. 1, no. 32, pp. 9303–9311, 2013. View at Publisher · View at Google Scholar · View at Scopus
  50. Y.-T. Chu, K. Chanda, P.-H. Lin, and M. H. Huang, “Aqueous phase synthesis of palladium tripod nanostructures for Sonogashira coupling reactions,” Langmuir, vol. 28, no. 30, pp. 11258–11264, 2012. View at Publisher · View at Google Scholar · View at Scopus
  51. M. Radtke, S. Stumpf, B. Schröter, S. Höppener, U. S. Schubert, and A. Ignaszak, “Electrodeposited palladium on MWCNTs as “semi-soluble heterogeneous” catalyst for cross-coupling reactions,” Tetrahedron Letters, vol. 56, no. 27, pp. 4084–4087, 2015. View at Publisher · View at Google Scholar · View at Scopus
  52. S.-J. Kim, S.-D. Oh, S. Lee, and S.-H. Choi, “Radiolytic synthesis of Pd-M (, Ni, and Cu)/C catalyst and their use in Suzuki-type and Heck-type reaction,” Journal of Industrial and Engineering Chemistry, vol. 14, no. 4, pp. 449–456, 2008. View at Publisher · View at Google Scholar · View at Scopus
  53. K. Lamei, H. Eshghi, M. Bakavoli, S. A. Rounaghi, and E. Esmaeili, “Carbon coated copper nanostructures as a green and ligand free nanocatalyst for Suzuki cross-coupling reaction,” Catalysis Communications, vol. 92, pp. 40–45, 2017. View at Publisher · View at Google Scholar · View at Scopus
  54. H. Veisi and A. Kakanejadifard, “Immobilization of palladium nanoparticles on ionic liquid-triethylammonium chloride functionalized magnetic nanoparticles: as a magnetically separable, stable and recyclable catalyst for Suzuki-Miyaura cross-coupling reactions,” Tetrahedron Letters, vol. 58, no. 45, pp. 4269–4276, 2017. View at Publisher · View at Google Scholar · View at Scopus
  55. Y. Li, X. Fan, J. Qi et al., “Gold nanoparticles-graphene hybrids as active catalysts for Suzuki reaction,” Materials Research Bulletin, vol. 45, no. 10, pp. 1413–1418, 2010. View at Publisher · View at Google Scholar · View at Scopus
  56. M. Nasrollahzadeh and S. M. Sajadi, “Green synthesis, characterization and catalytic activity of the Pd/TiO2 nanoparticles for the ligand-free Suzuki-Miyaura coupling reaction,” Journal of Colloid and Interface Science, vol. 465, pp. 121–127, 2016. View at Publisher · View at Google Scholar · View at Scopus
  57. Y. Na, S. Park, S. B. Han, H. Han, S. Ko, and S. Chang, “Ruthenium-catalyzed Heck-type olefination and Suzuki coupling reactions: studies on the nature of catalytic species,” Journal of the American Chemical Society, vol. 126, no. 1, pp. 250–258, 2004. View at Publisher · View at Google Scholar
  58. P. M. Uberman, L. A. Pérez, G. I. Lacconi, and S. E. Martín, “PVP-stabilized palladium nanoparticles electrochemically obtained as effective catalysts in aqueous medium Suzuki-Miyaura reaction,” Journal of Molecular Catalysis A: Chemical, vol. 363, pp. 245–253, 2012. View at Publisher · View at Google Scholar · View at Scopus
  59. N. Ghanbari, S. J. Hoseini, and M. Bahrami, “Ultrasonic assisted synthesis of palladium-nickel/iron oxide core-shell nanoalloys as effective catalyst for Suzuki-Miyaura and p-nitrophenol reduction reactions,” Ultrasonics Sonochemistry, vol. 39, pp. 467–477, 2017. View at Publisher · View at Google Scholar · View at Scopus
  60. S. J. Hoseini, M. Dehghani, and H. Nasrabadi, “Thin film formation of Pd/reduced-graphene oxide and Pd nanoparticles at oil-water interface, suitable as effective catalyst for Suzuki-Miyaura reaction in water,” Catalysis Science & Technology, vol. 4, no. 4, pp. 1078–1083, 2014. View at Publisher · View at Google Scholar · View at Scopus
  61. L. Shiyong, Q. Zhou, Z. Jin, H. Jiang, and X. Jiang, “Dodecylsulfate anion embedded layered double hydroxide supported nanopalladium catalyst for the Suzuki reaction,” Chinese Journal of Catalysis, vol. 31, no. 5, pp. 557–561, 2010. View at Publisher · View at Google Scholar
  62. P. Mondal, P. Bhanja, R. Khatun, A. Bhaumik, D. Das, and S. M. Islam, “Palladium nanoparticles embedded on mesoporous TiO2 material (Pd@MTiO2) as an efficient heterogeneous catalyst for Suzuki-coupling reactions in water medium,” Journal of Colloid and Interface Science, vol. 508, pp. 378–386, 2017. View at Publisher · View at Google Scholar · View at Scopus
  63. M. Shokouhimehr, T. Kim, S. W. Jun et al., “Magnetically separable carbon nanocomposite catalysts for efficient nitroarene reduction and Suzuki reactions,” Applied Catalysis A: General, vol. 476, pp. 133–139, 2014. View at Publisher · View at Google Scholar · View at Scopus
  64. J. Xia, Y. Fu, G. He, X. Sun, and X. Wang, “Core-shell-like Ni-Pd nanoparticles supported on carbon black as a magnetically separable catalyst for green Suzuki-Miyaura coupling reactions,” Applied Catalysis B: Environmental, vol. 200, pp. 39–46, 2017. View at Publisher · View at Google Scholar · View at Scopus
  65. P. Mondal, N. Salam, A. Mondal, K. Ghosh, K. Tuhina, and S. M. Islam, “A highly active recyclable gold-graphene nanocomposite material for oxidative esterification and Suzuki cross-coupling reactions in green pathway,” Journal of Colloid and Interface Science, vol. 459, pp. 97–106, 2015. View at Publisher · View at Google Scholar · View at Scopus
  66. M. Thomas, M. U. D. Sheikh, D. Ahirwar, M. Bano, and F. Khan, “Gold nanoparticle and graphene oxide incorporated strontium crosslinked alginate/carboxymethyl cellulose composites for o-nitroaniline reduction and Suzuki-Miyaura cross-coupling reactions,” Journal of Colloid and Interface Science, vol. 505, pp. 115–129, 2017. View at Publisher · View at Google Scholar · View at Scopus
  67. Y. Kiso, K. Yamamoto, K. Tamao, and M. Kumada, “Asymmetric homogeneous hydrosilylation with chiral phosphine-palladium complexes,” Journal of the American Chemical Society, vol. 94, no. 12, pp. 4373-4374, 1972. View at Publisher · View at Google Scholar · View at Scopus
  68. J. K. Stille and K. S. Y. Lau, “Mechanisms of oxidative addition of organic halides to group 8 transition-metal complexes,” Accounts of Chemical Research, vol. 10, no. 12, pp. 434–442, 1977. View at Publisher · View at Google Scholar · View at Scopus
  69. F. Panahi, F. Daneshgar, F. Haghighi, and A. Khalafi-Nezhad, “Immobilized Pd nanoparticles on silica-starch substrate (PNP-SSS): efficient heterogeneous catalyst in Buchwald-Hartwig C-N cross coupling reaction,” Journal of Organometallic Chemistry, vol. 851, pp. 210–217, 2017. View at Publisher · View at Google Scholar · View at Scopus
  70. A. R. Hajipour, Z. Khorsandi, and S. F. M. Metkazini, “Palladium nanoparticles supported on cysteine-functionalized MNPs as robust recyclable catalysts for fast O-and N-arylation reactions in green media,” Journal of Organometallic Chemistry, vol. 899, article 120793, 2019. View at Publisher · View at Google Scholar
  71. H. Veisi, P. Safarimehr, and S. Hemmati, “Buchwald-Hartwig C-N cross coupling reactions catalyzed by palladium nanoparticles immobilized on thio modified-multi walled carbon nanotubes as heterogeneous and recyclable nanocatalyst,” Materials Science and Engineering: C, vol. 96, pp. 310–318, 2019. View at Publisher · View at Google Scholar · View at Scopus
  72. S. Santra, P. Ranjan, S. K. Mandal, and P. K. Ghorai, “Living nanocatalyst for effective synthesis of symmetrical biaryls,” Inorganica Chimica Acta, vol. 372, no. 1, pp. 47–52, 2011. View at Publisher · View at Google Scholar · View at Scopus
  73. F. Rafiee, P. Khavari, Z. Payami, and N. Ansari, “Palladium nanoparticles immobilized on the magnetic few layer graphene support as a highly efficient catalyst for ligand free Suzuki cross coupling and homo coupling reactions,” Journal of Organometallic Chemistry, vol. 883, pp. 78–85, 2019. View at Publisher · View at Google Scholar · View at Scopus
  74. Y. Liu, D. Tang, K. Cao, L. Yu, J. Han, and Q. Xu, “Probing the support effect at the molecular level in the polyaniline-supported palladium nanoparticle-catalyzed Ullmann reaction of aryl iodides,” Journal of Catalysis, vol. 360, pp. 250–260, 2018. View at Publisher · View at Google Scholar · View at Scopus
  75. F. Chang, H. Kim, B. Lee, S. Park, and J. Park, “Highly efficient solvent-free catalytic hydrogenation of solid alkenes and nitro-aromatics using Pd nanoparticles entrapped in aluminum oxy-hydroxide,” Tetrahedron Letters, vol. 51, no. 32, pp. 4250–4252, 2010. View at Publisher · View at Google Scholar · View at Scopus
  76. D. Fry and K. O’Connor, “The solvent-less hydrogenation of unsaturated esters using 0.5% Pd/Al (O) OH as a catalyst,” The Chemical Educator, vol. 18, pp. 144–146, 2013. View at Google Scholar
  77. W. Tu, K. Li, X. Shu, and W. W. Yu, “Reduction of hexavalent chromium with colloidal and supported palladium nanocatalysts,” Journal of Nanoparticle Research, vol. 15, no. 4, pp. 1–9, 2013. View at Publisher · View at Google Scholar · View at Scopus
  78. C. Yang, J. H. Meldon, B. Lee, and H. Yi, “Investigation on the catalytic reduction kinetics of hexavalent chromium by viral-templated palladium nanocatalysts,” Catalysis Today, vol. 233, pp. 108–116, 2014. View at Publisher · View at Google Scholar · View at Scopus
  79. C. Yang, A. K. Manocchi, B. Lee, and H. Yi, “Viral templated palladium nanocatalysts for dichromate reduction,” Applied Catalysis B: Environmental, vol. 93, no. 3, pp. 282–291, 2010. View at Publisher · View at Google Scholar · View at Scopus
  80. S. Karaboga and S. Özkar, “Nanoalumina supported palladium(0) nanoparticle catalyst for releasing H2 from dimethylamine borane,” Applied Surface Science, vol. 487, pp. 433–441, 2019. View at Publisher · View at Google Scholar
  81. J. V. Rojas and C. H. Castano, “Production of palladium nanoparticles supported on multiwalled carbon nanotubes by gamma irradiation,” Radiation Physics and Chemistry, vol. 81, no. 1, pp. 16–21, 2012. View at Publisher · View at Google Scholar · View at Scopus
  82. I. Miguel-García, Á. Berenguer-Murcia, T. García, and D. Cazorla-Amorós, “Effect of the aging time of PVP coated palladium nanoparticles colloidal suspensions on their catalytic activity in the preferential oxidation of CO,” Catalysis Today, vol. 187, no. 1, pp. 2–9, 2012. View at Publisher · View at Google Scholar · View at Scopus
  83. X. Le, Z. Dong, X. Li, W. Zhang, M. Le, and J. Ma, “Fibrous nano-silica supported palladium nanoparticles: an efficient catalyst for the reduction of 4-nitrophenol and hydrodechlorination of 4-chlorophenol under mild conditions,” Catalysis Communications, vol. 59, pp. 21–25, 2015. View at Publisher · View at Google Scholar · View at Scopus
  84. M. Gholinejad and A. Aminianfar, “Palladium nanoparticles supported on magnetic copper ferrite nanoparticles: the synergistic effect of palladium and copper for cyanation of aryl halides with K4[Fe(CN)6],” Journal of Molecular Catalysis A: Chemical, vol. 397, pp. 106–113, 2015. View at Publisher · View at Google Scholar · View at Scopus
  85. M. M. Dell’Anna, V. F. Capodiferro, M. Mali et al., “Highly selective hydrogenation of quinolines promoted by recyclable polymer supported palladium nanoparticles under mild conditions in aqueous medium,” Applied Catalysis A: General, vol. 481, no. 0, pp. 89–95, 2014. View at Publisher · View at Google Scholar · View at Scopus
  86. C. Shang, W. Hong, J. Wang, and E. Wang, “Carbon supported trimetallic nickel-palladium-gold hollow nanoparticles with superior catalytic activity for methanol electrooxidation,” Journal of Power Sources, vol. 285, pp. 12–15, 2015. View at Publisher · View at Google Scholar · View at Scopus
  87. M. Gómez-Martínez, E. Buxaderas, I. M. Pastor, and D. A. Alonso, “Palladium nanoparticles supported on graphene and reduced graphene oxide as efficient recyclable catalyst for the Suzuki-Miyaura reaction of potassium aryltrifluoroborates,” Journal of Molecular Catalysis A: Chemical, vol. 404–405, pp. 1–7, 2015. View at Publisher · View at Google Scholar · View at Scopus
  88. K. H. Liew, W. Z. Samad, N. Nordin et al., “Preparation and characterization of HypoGel-supported Pd nanocatalysts for Suzuki reaction under mild conditions,” Chinese Journal of Catalysis, vol. 36, no. 5, pp. 771–777, 2015. View at Publisher · View at Google Scholar · View at Scopus
  89. Y. Liu, C. Khemtong, and J. Hu, “Synthesis and catalytic activity of a poly(N,N-dialkylcarbodiimide)/palladium nanoparticle composite: a case in the Suzuki coupling reaction using microwave and conventional heating,” Chemical Communications, no. 4, pp. 398-399, 2004. View at Publisher · View at Google Scholar · View at Scopus
  90. C.-C. Chen, C.-L. Lin, and L.-C. Chen, “Functionalized carbon nanomaterial supported palladium nano-catalysts for electrocatalytic glucose oxidation reaction,” Electrochimica Acta, vol. 152, pp. 408–416, 2015. View at Publisher · View at Google Scholar · View at Scopus
  91. R. Serra-Maia, S. Chastka, M. Bellier, T. Douglas, J. D. Rimstidt, and F. M. Michel, “Effect of particle size on catalytic decomposition of hydrogen peroxide by platinum nanocatalysts,” Journal of Catalysis, vol. 373, pp. 58–66, 2019. View at Publisher · View at Google Scholar · View at Scopus
  92. W. Liu, K. Hiekel, R. Hübner, H. Sun, A. Ferancova, and M. Sillanpää, “Pt and Au bimetallic and monometallic nanostructured amperometric sensors for direct detection of hydrogen peroxide: influences of bimetallic effect and silica support,” Sensors and Actuators B: Chemical, vol. 255, pp. 1325–1334, 2017. View at Publisher · View at Google Scholar · View at Scopus
  93. J. Lin, V. Kamavaram, and A. Kannan, “Synthesis and characterization of carbon nanotubes supported platinum nanocatalyst for proton exchange membrane fuel cells,” Journal of Power Sources, vol. 195, no. 2, pp. 466–470, 2010. View at Publisher · View at Google Scholar · View at Scopus
  94. C. Berghian-Grosan, T. Radu, A. R. Biris et al., “Platinum nanoparticles coated by graphene layers: a low-metal loading catalyst for methanol oxidation in alkaline media,” Journal of Energy Chemistry, vol. 40, pp. 81–88, 2020. View at Publisher · View at Google Scholar
  95. H. Gobara, R. S. Mohamed, F. H. Khalil, M. S. El-Shall, and S. A. Hassan, “Various characteristics of Ni and Pt-Al2O3 nanocatalysts prepared by microwave method to be applied in some petrochemical processes,” Egyptian Journal of Petroleum, vol. 23, no. 1, pp. 105–118, 2014. View at Publisher · View at Google Scholar · View at Scopus
  96. E. Gharibshahi, E. Saion, A. Ashraf, and L. Gharibshahi, “Size-controlled and optical properties of platinum nanoparticles by gamma radiolytic synthesis,” Applied Radiation and Isotopes, vol. 130, pp. 211–217, 2017. View at Publisher · View at Google Scholar · View at Scopus
  97. J. Lai, W. Niu, R. Luque, and G. Xu, “Solvothermal synthesis of metal nanocrystals and their applications,” Nano Today, vol. 10, no. 2, pp. 240–267, 2015. View at Publisher · View at Google Scholar · View at Scopus
  98. Y. Yang, L.-M. Luo, J.-J. Du et al., “Facile one-pot hydrothermal synthesis and electrochemical properties of carbon nanospheres supported Pt nanocatalysts,” International Journal of Hydrogen Energy, vol. 41, no. 28, pp. 12062–12068, 2016. View at Publisher · View at Google Scholar · View at Scopus
  99. A. Chen and P. Holt-Hindle, “Platinum-based nanostructured materials: synthesis, properties, and applications,” Chemical Reviews, vol. 110, no. 6, pp. 3767–3804, 2010. View at Publisher · View at Google Scholar · View at Scopus
  100. F. Ye, W. Hu, T. Zhang, J. Yang, and Y. Ding, “Enhanced electrocatalytic activity of Pt-nanostructures prepared by electrodeposition using poly(vinyl pyrrolidone) as a shape-control agent,” Electrochimica Acta, vol. 83, pp. 383–386, 2012. View at Publisher · View at Google Scholar · View at Scopus
  101. K. A. Manbeck, N. E. Musselwhite, L. M. Carl et al., “Factors affecting activity and selectivity during cyclohexanone hydrogenation with colloidal platinum nanocatalysts,” Applied Catalysis A: General, vol. 384, no. 1-2, pp. 58–64, 2010. View at Publisher · View at Google Scholar · View at Scopus
  102. R. Narayanan and M. A. El-Sayed, “Effect of colloidal nanocatalysis on the metallic nanoparticle shape: the Suzuki reaction,” Langmuir, vol. 21, no. 5, pp. 2027–2033, 2005. View at Publisher · View at Google Scholar · View at Scopus
  103. C. Dai, C. Wang, R. Hu et al., “Photonic/magnetic hyperthermia-synergistic nanocatalytic cancer therapy enabled by zero-valence iron nanocatalysts,” Biomaterials, vol. 219, article 119374, 2019. View at Publisher · View at Google Scholar
  104. A. R. Hajipour and P. Abolfathi, “Nickel embedded on triazole-modified magnetic nanoparticles: a novel and sustainable heterogeneous catalyst for Hiyama reaction in fluoride-free condition,” Catalysis Communications, vol. 103, pp. 92–95, 2017. View at Publisher · View at Google Scholar · View at Scopus
  105. M. Hałupka-Bryl, M. Bednarowicz, B. Dobosz et al., “Doxorubicin loaded PEG-b-poly(4-vinylbenzylphosphonate) coated magnetic iron oxide nanoparticles for targeted drug delivery,” Journal of Magnetism and Magnetic Materials, vol. 384, pp. 320–327, 2015. View at Publisher · View at Google Scholar · View at Scopus
  106. L. Li, C. Zeng, L. Ai, and J. Jiang, “Synthesis of reduced graphene oxide-iron nanoparticles with superior enzyme-mimetic activity for biosensing application,” Journal of Alloys and Compounds, vol. 639, pp. 470–477, 2015. View at Publisher · View at Google Scholar · View at Scopus
  107. H. J. Kim, S.-M. Lee, K.-H. Park, C. H. Mun, Y.-B. Park, and K.-H. Yoo, “Drug-loaded gold/iron/gold plasmonic nanoparticles for magnetic targeted chemo-photothermal treatment of rheumatoid arthritis,” Biomaterials, vol. 61, pp. 95–102, 2015. View at Publisher · View at Google Scholar · View at Scopus
  108. D.-W. Cho, H. Song, F. W. Schwartz, B. Kim, and B.-H. Jeon, “The role of magnetite nanoparticles in the reduction of nitrate in groundwater by zero-valent iron,” Chemosphere, vol. 125, pp. 41–49, 2015. View at Publisher · View at Google Scholar · View at Scopus
  109. A. Saritha, B. Raju, D. N. Rao, A. Roychowdhury, D. Das, and K. A. Hussain, “Facile green synthesis of iron oxide nanoparticles via solid-state thermolysis of a chiral, 3D anhydrous potassium tris(oxalato)ferrate(III) precursor,” Advanced Powder Technology, vol. 26, no. 2, pp. 349–354, 2015. View at Publisher · View at Google Scholar · View at Scopus
  110. J. Castelló, M. Gallardo, M. A. Busquets, and J. Estelrich, “Chitosan (or alginate)-coated iron oxide nanoparticles: a comparative study,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 468, pp. 151–158, 2015. View at Publisher · View at Google Scholar · View at Scopus
  111. R. Li, Y. Gao, X. Jin, Z. Chen, M. Megharaj, and R. Naidu, “Fenton-like oxidation of 2,4-DCP in aqueous solution using iron-based nanoparticles as the heterogeneous catalyst,” Journal of Colloid and Interface Science, vol. 438, pp. 87–93, 2015. View at Publisher · View at Google Scholar · View at Scopus
  112. J. Park, E. Lee, N.-M. Hwang et al., “One-nanometer-scale size-controlled synthesis of monodisperse magnetic iron oxide nanoparticles,” Angewandte Chemie, vol. 117, no. 19, pp. 2932–2937, 2005. View at Publisher · View at Google Scholar
  113. L. C. Varanda, M. Jafelicci, P. Tartaj et al., “Structural and magnetic transformation of monodispersed iron oxide particles in a reducing atmosphere,” Journal of Applied Physics, vol. 92, no. 4, pp. 2079–2085, 2002. View at Publisher · View at Google Scholar · View at Scopus
  114. F. Dumestre, B. Chaudret, C. Amiens, P. Renaud, and P. Fejes, “Superlattices of iron nanocubes synthesized from Fe[N (SiMe3)2]2,” Science, vol. 303, no. 5659, pp. 821–823, 2004. View at Publisher · View at Google Scholar · View at Scopus
  115. R. V. Jagadeesh, T. Stemmler, A.-E. Surkus, H. Junge, K. Junge, and M. Beller, “Hydrogenation using iron oxide-based nanocatalysts for the synthesis of amines,” Nature Protocols, vol. 10, no. 4, pp. 548–557, 2015. View at Publisher · View at Google Scholar · View at Scopus
  116. J. Wu, G. Gao, Y. Li, P. Sun, J. Wang, and F. Li, “Highly chemoselective hydrogenation of lactone to diol over efficient copper-based bifunctional nanocatalysts,” Applied Catalysis B: Environmental, vol. 245, pp. 251–261, 2019. View at Publisher · View at Google Scholar · View at Scopus
  117. H. Ajamein, M. Haghighi, R. Shokrani, and M. Abdollahifar, “On the solution combustion synthesis of copper based nanocatalysts for steam methanol reforming: effect of precursor, ultrasound irradiation and urea/nitrate ratio,” Journal of Molecular Catalysis A: Chemical, vol. 421, pp. 222–234, 2016. View at Publisher · View at Google Scholar · View at Scopus
  118. S. B. Bagherzadeh and M. Haghighi, “Plasma-enhanced comparative hydrothermal and coprecipitation preparation of CuO/ZnO/Al2O3 nanocatalyst used in hydrogen production via methanol steam reforming,” Energy Conversion and Management, vol. 142, pp. 452–465, 2017. View at Publisher · View at Google Scholar · View at Scopus
  119. S. Allahyari, M. Haghighi, A. Ebadi, and S. Hosseinzadeh, “Ultrasound assisted co-precipitation of nanostructured CuO-ZnO-Al2O3 over HZSM-5: effect of precursor and irradiation power on nanocatalyst properties and catalytic performance for direct syngas to DME,” Ultrasonics Sonochemistry, vol. 21, no. 2, pp. 663–673, 2014. View at Publisher · View at Google Scholar · View at Scopus
  120. J. Baneshi, M. Haghighi, N. Jodeiri, M. Abdollahifar, and H. Ajamein, “Homogeneous precipitation synthesis of CuO-ZrO2-CeO2-Al2O3 nanocatalyst used in hydrogen production via methanol steam reforming for fuel cell applications,” Energy Conversion and Management, vol. 87, pp. 928–937, 2014. View at Publisher · View at Google Scholar · View at Scopus
  121. S. Danwittayakul and J. Dutta, “Two step copper impregnated zinc oxide microball synthesis for the reduction of activation energy of methanol steam reformation,” Chemical Engineering Journal, vol. 223, pp. 304–308, 2013. View at Publisher · View at Google Scholar · View at Scopus
  122. M. Haruta, N. Yamada, T. Kobayashi, and S. Iijima, “Gold catalysts prepared by coprecipitation for low-temperature oxidation of hydrogen and of carbon monoxide,” Journal of Catalysis, vol. 115, no. 2, pp. 301–309, 1989. View at Publisher · View at Google Scholar · View at Scopus
  123. J. Papavasiliou, “Interaction of atomically dispersed gold with hydrothermally prepared copper-cerium oxide for preferential CO oxidation reaction,” Catalysis Today, 2019. View at Publisher · View at Google Scholar · View at Scopus
  124. L. Qin, G. Zeng, C. Lai et al., “Synthetic strategies and application of gold-based nanocatalysts for nitroaromatics reduction,” Science of the Total Environment, vol. 652, pp. 93–116, 2018. View at Publisher · View at Google Scholar · View at Scopus
  125. X. Sun, F. Li, J. Shi et al., “Gold nanoparticles supported on MgOx-Al2O3 composite oxide: an efficient catalyst for selective hydrogenation of acetylene,” Applied Surface Science, vol. 487, pp. 625–633, 2019. View at Publisher · View at Google Scholar
  126. A. Monopoli, A. Afzal, C. di Franco et al., “Design of novel indium oxide supported gold nanocatalysts and their application in homocoupling of arylboronic acids,” Journal of Molecular Catalysis A: Chemical, vol. 386, pp. 101–107, 2014. View at Publisher · View at Google Scholar · View at Scopus
  127. H. S. Devi, N. R. Singh, H. P. Singh, and T. D. Singh, “Facile synthesis of biogenic gold nanocatalyst for efficient degradation of organic pollutants,” Journal of Environmental Chemical Engineering, vol. 3, no. 3, pp. 2042–2049, 2015. View at Publisher · View at Google Scholar · View at Scopus
  128. T. Xiao, J. Huang, D. Wang, T. Meng, and X. Yang, “Au and Au-based nanomaterials: synthesis and recent progress in electrochemical sensor applications,” Talanta, vol. 206, article 120210, 2019. View at Publisher · View at Google Scholar
  129. A. E. Shanahan, M. McNamara, J. A. Sullivan, and H. J. Byrne, “An insight into the superior performance of a gold nanocatalyst on single wall carbon nanotubes to that on titanium dioxide and amorphous carbon for the green aerobic oxidation of aromatic alcohols,” New Carbon Materials, vol. 32, no. 3, pp. 242–251, 2017. View at Publisher · View at Google Scholar · View at Scopus
  130. S. Chairam, W. Konkamdee, and R. Parakhun, “Starch-supported gold nanoparticles and their use in 4-nitrophenol reduction,” Journal of Saudi Chemical Society, vol. 21, no. 6, pp. 656–663, 2015. View at Publisher · View at Google Scholar · View at Scopus
  131. A. Shajkumar, B. Nandan, S. Sanwaria et al., “Silica-supported Au@ hollow-SiO2 particles with outstanding catalytic activity prepared via block copolymer template approach,” Journal of Colloid and Interface Science, vol. 491, pp. 246–254, 2017. View at Publisher · View at Google Scholar · View at Scopus
  132. P. Sudarsanam, B. Mallesham, A. Rangaswamy, B. G. Rao, S. K. Bhargava, and B. M. Reddy, “Promising nanostructured gold/metal oxide catalysts for oxidative coupling of benzylamines under eco-friendly conditions,” Journal of Molecular Catalysis A: Chemical, vol. 412, pp. 47–55, 2016. View at Publisher · View at Google Scholar · View at Scopus
  133. D. Shah and H. Kaur, “Resin-trapped gold nanoparticles: an efficient catalyst for reduction of nitro compounds and Suzuki-Miyaura coupling,” Journal of Molecular Catalysis A: Chemical, vol. 381, pp. 70–76, 2014. View at Publisher · View at Google Scholar · View at Scopus
  134. C. Wang, H. Yin, S. Dai, and S. Sun, “A general approach to noble metal-metal oxide dumbbell nanoparticles and their catalytic application for CO oxidation,” Chemistry of Materials, vol. 22, no. 10, pp. 3277–3282, 2010. View at Publisher · View at Google Scholar · View at Scopus
  135. Y. Lee, M. A. Garcia, N. A. Frey Huls, and S. Sun, “Synthetic tuning of the catalytic properties of Au-Fe3O4 nanoparticles,” Angewandte Chemie International Edition, vol. 49, no. 7, pp. 1271–1274, 2010. View at Publisher · View at Google Scholar · View at Scopus
  136. F. Lin and R. Doong, “Bifunctional Au-Fe3O4 heterostructures for magnetically recyclable catalysis of nitrophenol reduction,” The Journal of Physical Chemistry C, vol. 115, no. 14, pp. 6591–6598, 2011. View at Publisher · View at Google Scholar · View at Scopus
  137. H. Veisi, N. Dadres, P. Mohammadi, and S. Hemmati, “Green synthesis of silver nanoparticles based on oil-water interface method with essential oil of orange peel and its application as nanocatalyst for A3 coupling,” Materials Science and Engineering: C, vol. 105, article 110031, 2019. View at Publisher · View at Google Scholar
  138. R. Sedghi, S. Asadi, B. Heidari, and M. M. Heravi, “TiO2/polymeric supported silver nanoparticles applied as superior nanocatalyst in reduction reactions,” Materials Research Bulletin, vol. 92, pp. 65–73, 2017. View at Publisher · View at Google Scholar · View at Scopus
  139. P. Paul, P. Bhanja, N. Salam et al., “Silver nanoparticles supported over mesoporous alumina as an efficient nanocatalyst for N-alkylation of hetero (aromatic) amines and aromatic amines using alcohols as alkylating agent,” Journal of Colloid and Interface Science, vol. 493, pp. 206–217, 2017. View at Publisher · View at Google Scholar · View at Scopus
  140. Y. Junejo and M. Safdar, “Highly effective heterogeneous doxycycline stabilized silver nanocatalyst for the degradation of ibuprofen and paracetamol drugs,” Arabian Journal of Chemistry, 2015. View at Publisher · View at Google Scholar · View at Scopus
  141. Q. Yi, H. Chu, M. Tang, Z. Yang, Q. Chen, and X. Liu, “Carbon nanotube-supported binary silver-based nanocatalysts for oxygen reduction reaction in alkaline media,” Journal of Electroanalytical Chemistry, vol. 739, pp. 178–186, 2015. View at Publisher · View at Google Scholar · View at Scopus
  142. B. K. Ghosh, D. Moitra, M. Chandel, H. Lulla, and N. N. Ghosh, “Ag nanoparticle immobilized mesoporous TiO2-cobalt ferrite nanocatalyst: a highly active, versatile, magnetically separable and reusable catalyst,” Materials Research Bulletin, vol. 94, pp. 361–370, 2017. View at Publisher · View at Google Scholar · View at Scopus
  143. U. Mandi, A. S. Roy, S. K. Kundu, S. Roy, A. Bhaumik, and S. M. Islam, “Mesoporous polyacrylic acid supported silver nanoparticles as an efficient catalyst for reductive coupling of nitrobenzenes and alcohols using glycerol as hydrogen source,” Journal of Colloid and Interface Science, vol. 472, pp. 202–209, 2016. View at Publisher · View at Google Scholar · View at Scopus
  144. Z. Ye, L. Hu, J. Jiang, J. Tang, X. Cao, and H. Gu, “CuO@Ag as a highly active catalyst for the selective oxidation of trans-stilbene and alcohols,” Catalysis Science & Technology, vol. 2, no. 6, pp. 1146–1149, 2012. View at Publisher · View at Google Scholar · View at Scopus
  145. C. Chen, J. Qu, C. Cao, F. Niu, and W. Song, “CuO nanoclusters coated with mesoporous SiO2 as highly active and stable catalysts for olefin epoxidation,” Journal of Materials Chemistry, vol. 21, no. 15, pp. 5774–5779, 2011. View at Publisher · View at Google Scholar · View at Scopus
  146. M. J. Borah, A. Devi, R. Borah, and D. Deka, “Synthesis and application of Co doped ZnO as heterogeneous nanocatalyst for biodiesel production from non-edible oil,” Renewable Energy, vol. 133, pp. 512–519, 2019. View at Publisher · View at Google Scholar · View at Scopus
  147. E. Vessally, M. Babazadeh, A. Hosseinian, S. Arshadi, and L. Edjlali, “Nanocatalysts for chemical transformation of carbon dioxide,” Journal of CO2 Utilization, vol. 21, pp. 491–502, 2017. View at Publisher · View at Google Scholar · View at Scopus
  148. A. Esmaeili and S. Kakavand, “Nanocomposites with different metals as magnetically separable nanocatalysts for oxidation of aldehydes,” Comptes Rendus Chimie, vol. 19, no. 8, pp. 936–941, 2016. View at Publisher · View at Google Scholar · View at Scopus
  149. R. Madhuvilakku and S. Piraman, “Biodiesel synthesis by TiO2-ZnO mixed oxide nanocatalyst catalyzed palm oil transesterification process,” Bioresource Technology, vol. 150, pp. 55–59, 2013. View at Publisher · View at Google Scholar · View at Scopus
  150. R. Bharati and S. Suresh, “Biosynthesis of ZnO/SiO2 nanocatalyst with palash leaves’ powder for treatment of petroleum refinery effluent,” Resource-Efficient Technologies, vol. 3, no. 4, pp. 528–541, 2017. View at Publisher · View at Google Scholar
  151. G. R. Andrade, C. C. Nascimento, E. C. Silva Júnior, D. T. S. L. Mendes, and I. F. Gimenez, “ZnO/Au nanocatalysts for enhanced decolorization of an azo dye under solar, UV-A and dark conditions,” Journal of Alloys and Compounds, vol. 710, pp. 557–566, 2017. View at Publisher · View at Google Scholar · View at Scopus
  152. J. Albadi, A. Alihosseinzadeh, and M. Mardani, “Efficient approach for the chemoselective acetylation of alcohols catalyzed by a novel metal oxide nanocatalyst CuO-ZnO,” Chinese Journal of Catalysis, vol. 36, no. 3, pp. 308–313, 2015. View at Publisher · View at Google Scholar · View at Scopus
  153. H. Ajamein, M. Haghighi, and S. Alaei, “The role of various fuels on microwave-enhanced combustion synthesis of CuO/ZnO/Al2O3 nanocatalyst used in hydrogen production via methanol steam reforming,” Energy Conversion and Management, vol. 137, pp. 61–73, 2017. View at Publisher · View at Google Scholar · View at Scopus
  154. S. Minaei, M. Haghighi, N. Jodeiri, H. Ajamein, and M. Abdollahifar, “Urea-nitrates combustion preparation of CeO2-promoted CuO/ZnO/Al2O3 nanocatalyst for fuel cell grade hydrogen production via methanol steam reforming,” Advanced Powder Technology, vol. 28, no. 3, pp. 842–853, 2017. View at Publisher · View at Google Scholar · View at Scopus
  155. K. Ranjith and R. R. Kumar, “Surfactant free, simple, morphological and defect engineered ZnO nanocatalyst: effective study on sunlight driven and reusable photocatalytic properties,” Journal of Photochemistry and Photobiology A: Chemistry, vol. 329, pp. 35–45, 2016. View at Publisher · View at Google Scholar · View at Scopus
  156. I. Saikia, M. Hazarika, and C. Tamuly, “Synthesis, characterization of bio-derived ZnO nanoparticles and its catalytic activity,” Materials Letters, vol. 161, pp. 29–32, 2015. View at Publisher · View at Google Scholar · View at Scopus