http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2013 , Hindawi Publishing Corporation . All rights reserved. Wed, 15 May 2013 17:30:23 +0000 http://www.hindawi.com/journals/catalysts/2013/828962/ Isomerization of -butane was studied on silica-supported heteropolyacids. The activity depends strongly on the solvent used for the preparation and on the polyoxometalate loading. This behavior was explained by different proportions of isolated and bulk heteropolyacids. Silicotungstic acid is inherently more selective than phosphotungstic acid. In presence of platinum and hydrogen the catalysts are stable and highly selective (more than 97%) to isobutane. A study as a function of temperature shows that there is an optimal temperature for performing the reaction. Eva Grinenval, Anthony Garron, and Frédéric Lefebvre Copyright © 2013 Eva Grinenval et al. All rights reserved. Tue, 16 Apr 2013 19:04:24 +0000 http://www.hindawi.com/journals/catalysts/2013/685063/ The transesterification of vegetable oils produces fatty acid methyl esters (biodiesel). Biodiesel is a nonpolluting alternative fuel produced from renewable resources whose chemical and physical properties closely resemble those of the petroleum diesel fuel and does not contribute to the greenhouse effect. The use of solid catalysts makes biodiesel production processes environmentally friendly. In this work, Mg,Al-mixed oxides derived from Mg,Al-hydrotalcite-like compound with an M3+/() molar ratio of 0.25, in which Mg or Al was partially replaced by Co2+, Cu2+, Cr3+, or Fe3+, were prepared, characterized, and evaluated as catalysts for the transesterification of soybean oil with methanol. The results have indicated that the incorporation of transition metal influenced both textural and base properties. All the evaluated catalysts were active for the studied reaction. The catalytic activity followed the order Cr-MO < Co-MO < Cu-MO < Fe-MO < MO and could be explained by mesoporous volume. Paula M. Veiga, Zilacleide S. B. Sousa, Carla M. S. Polato, Marcio F. Portilho, Cláudia O. Veloso, and Cristiane A. Henriques Copyright © 2013 Paula M. Veiga et al. All rights reserved. Thu, 04 Apr 2013 13:52:53 +0000 http://www.hindawi.com/journals/catalysts/2013/104019/ Visible-light-assisted photodegradation of an azo dye, Reactive Red 180 (RR180), in the presence of nitrogen-doped TiO2 (N-TiO2) has been studied. The photodegradation of RR180 is evaluated through decolorization studies and total organic carbon analysis. The efficacy of hydrogen peroxide (H2O2), potassium peroxomonosulfate (oxone or PMS), and potassium peroxodisulfate (PDS) in improving the photodegradation of the dye in the N-TiO2-RR180 system is also examined. The effect of combining photo-Fenton-like reaction with N-TiO2-mediated photodegradation of RR180 under visible light has been investigated. The photoactivity of N-TiO2-RR180-Fe3+/Cu2+-oxidant systems is compared with the individual techniques of photocatalysis and photo-Fenton-like reactions. The coupled system possesses superior photomineralization ability towards the abatement of RR180. Selma K. Kuriechen, Sepperumal Murugesan, and Samuel Paul Raj Copyright © 2013 Selma K. Kuriechen et al. All rights reserved. Thu, 04 Apr 2013 11:48:33 +0000 http://www.hindawi.com/journals/catalysts/2013/657409/ An efficient and environmental benign method is reported for the synthesis of some pyrazolopyrimidine derivatives using 3-methyl-1-phenyl-5-pyrazolone with carbonyl compounds in the presence of nanozeolite Nax catalysts, solvent-free and at reflux conditions. It is noteworthy to mention that this method of the synthesis requires less time, less temperature, and better yield. Ali Gharib, Manouchehr Jahangir, Mina Roshani, Sara Moghadasi, and Reza Safee Copyright © 2013 Ali Gharib et al. All rights reserved. Thu, 21 Mar 2013 14:40:36 +0000 http://www.hindawi.com/journals/catalysts/2013/586364/ A series of Au/-TiO2 with various Co/Ti ratios prepared. /TiO2 was prepared by incipient wetness impregnation with aqueous solution of cobalt nitrate. Au catalysts were prepared by deposition-precipitation (DP) method at pH 7 and 338 K. The catalysts were characterized by inductively coupled plasma-mass spectrometry, temperature programming reduction, X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The reaction was carried out in a fixed bed reactor with a feed containing 1% CO in air at weight hourly space velocities of 120,000 mL/h g and 180,000 mL/h g. High gold dispersion and narrow particle size distribution were obtained by DP method. The addition of into Au/TiO2 enhanced the activity of CO oxidation significantly. Au/5%  -TiO2 had the highest catalyst among all the catalysts. was mainly in the form of nanosize Co3O4 which could stabilize the Au nanoparticles. donated partial electrons to Au. The interactions among Au, , and TiO2 account for the high catalytic activity for CO oxidation. Der-Shing Lee and Yu-Wen Chen Copyright © 2013 Der-Shing Lee and Yu-Wen Chen. All rights reserved. Wed, 20 Mar 2013 13:42:52 +0000 http://www.hindawi.com/journals/catalysts/2013/942145/ Alkali-promoted Ni-Co-Mo catalysts supported on multiwalled carbon nanotubes (MWCNTs) were prepared using 9 wt% K, 4.5 wt% Co, and 15 wt% Mo, whereas Ni content was varied from 0 to 6 wt%. The catalysts were extensively characterized and studied for higher alcohols synthesis from synthesis gas. Alkali-promoted trimetallic catalyst with 3 wt% Ni showed the highest total alcohols yield of 0.284 gm/(gm of cat./h), ethanol selectivity of 20%, and higher alcohols selectivity of 32% at 330°C and 9.0 MPa using gas hourly space velocity (GHSV) of 3.8 m3 (STP)/kg of catalyst/h and H2 to CO molar ratio of 1.25. Venkateswara Rao Surisetty, Janusz Kozinski, and Ajay Kumar Dalai Copyright © 2013 Venkateswara Rao Surisetty et al. All rights reserved. Mon, 25 Feb 2013 11:38:34 +0000 http://www.hindawi.com/journals/catalysts/2013/582058/ A detailed investigation of photocatalytic degradation of Acid Yellow 36 (AY36) has been carried out in aqueous heterogeneous medium containing ZnO as photocatalyst in a batch reactor. The effects of some parameters such as pH, catalyst loading, and ethanol concentration were examined. Solutions with initial concentration of 50 mg L−1 of dye, within the range of typical concentration in textile wastewaters, were treated at natural pH of 6.93 and catalyst concentration of 1 g L−1 after 180 min irradiation. Investigations on the active species indicated that hydroxyl radicals play the major role in the process. Experiments showed that the most efficient pH on the removal of the dye with photocatalytic degradation process was 8; however, acidic pH was favored for the dark surface adsorption. Electrical energy consumption per order of magnitude for photocatalytic degradation of AY36 has been also determined. Sajjad Khezrianjoo and Hosakere Doddarevanna Revanasiddappa Copyright © 2013 Sajjad Khezrianjoo and Hosakere Doddarevanna Revanasiddappa. All rights reserved. Thu, 14 Feb 2013 10:31:31 +0000 http://www.hindawi.com/journals/catalysts/2013/392162/ Decatungstodivanadogermanic acid (H6GeW10V2O40·22H2O) was synthesized and used as a novel, green heterogeneous catalyst for the synthesis of spirofused heterocycles from one-pot three-component cyclocondensation reaction of a cyclic ketone, aldehyde, and urea in high yields under solvent-free condition in microwave irradiation at 80°C. This catalyst is efficient not only for cyclic ketones, but also for cyclic β-diketones, β-diester, and β-diamide derivatives such as cyclohexanone, dimedone, and Meldrum's acid, or barbituric acid derivatives. Srinivasa Rao Jetti, Divya Verma, and Shubha Jain Copyright © 2013 Srinivasa Rao Jetti et al. All rights reserved. Thu, 17 Jan 2013 15:05:38 +0000 http://www.hindawi.com/journals/catalysts/2013/376078/ A new class of porphyrin(Pp)/Fe co-loaded TiO2 composites opportunely prepared by impregnation of [5,10,15,20-tetra(4-tert-butylphenyl)] porphyrin (H2Pp) or Cu(II)[5,10,15,20-tetra(4-tert-butylphenyl)] porphyrin (CuPp) onto Fe-loaded TiO2 particles showed high activities by carrying out the degradation of 4-nitrophenol (4-NP) as probe reaction in aqueous suspension under heterogeneous photo-Fenton-like reactions by using UV-visible light. The combination of porphyrin-Fe-TiO2 in the presence of H2O2 showed to be more efficient than the simple bare TiO2 or Fe-TiO2. Giuseppe Mele, Iolanda Pio, Anna Scarlino, Ermelinda Bloise, Roberta Del Sole, Leonardo Palmisano, and Giuseppe Vasapollo Copyright © 2013 Giuseppe Mele et al. All rights reserved. Tue, 15 Jan 2013 08:04:47 +0000 http://www.hindawi.com/journals/catalysts/2013/910489/ A protocol for the preparation of iron oxide nanocrystals of two different (nanorods and octahedrons) morphologies has been developed and the synthesized nanocrystals were well characterized by TEM and XRD. These two nanocrystals have been applied for the selectivie oxidation of aryl-methanol and vinyl-arene. Moreover, the magnetic catalysts have easily separated from reaction mixture by a magnet and are reused without appreciable loss of catalytic activity. The oxidation processes avoid the use of toxic catalysts and volatile and hazardous organic solvents. Subhash Banerjee and Swadeshmukul Santra Copyright © 2013 Subhash Banerjee and Swadeshmukul Santra. All rights reserved. Mon, 14 Jan 2013 09:42:35 +0000 http://www.hindawi.com/journals/catalysts/2013/730978/ Methane is activated at moderate temperature on polyoxometalates, leading to the evolution of hydrogen and the formation of a methoxy species which has been characterized by solid-state CP-MAS NMR. In the case of a molybdic polyoxometalate, the methyl group is linked to an edge-shared oxygen atom of the polyoxometalate. Upon heating, it reacts with oxygens of the polyoxometalate resulting in the formation of formyl species and then carbon dioxide and a reduction of molybdenum. Upon treatment with water, only traces of methanol can be detected. Frédéric Lefebvre, Eva Grinenval, and Piotr Putaj Copyright © 2013 Frédéric Lefebvre et al. All rights reserved. Thu, 13 Dec 2012 09:42:07 +0000 http://www.hindawi.com/journals/catalysts/2013/276210/ A new approach to the synthesis of mixed-type immobilized catalysts by frontal polymerization of metal-containing monomer in the presence of highly dispersed mineral support has been developed. Synthesis of the acrylamide Pd(II) nitrate complex, Pd(CH2=CHCONH2)2 (NO3)2 (PdAAm), on the SiO2 (Al2O3, C) surface and its consequent frontal polymerization and reduction lead to the formation of organic-inorganic composites with polymer-stabilized Pd nanoparticles. The immobilized metal complexes and palladium nanoparticles were characterized by various physical and chemical methods. The synthesized hybrid nanocomposites are efficient and selective catalysts for hydrogenation of cyclohexene, alkene, and acetylene alcohols, as well as di- and trinitrotoluene. Catalyst intermediates separated by nondestructive testing method have been described and changing in the palladium charge during the catalytic process has been identified. Anatolii D. Pomogailo and Gulzhian I. Dzhardimalieva Copyright © 2013 Anatolii D. Pomogailo and Gulzhian I. Dzhardimalieva. All rights reserved. Mon, 26 Nov 2012 09:29:15 +0000 http://www.hindawi.com/journals/catalysts/2013/178512/ The photoelectrochemical response and catalytic efficiency towards phenol photooxidation of mesoporous titania particles with spherical morphology have been explored. The catalysts were synthesized in two different arrangements using carbon spheres in a dual role as support and morphology director: hollow spherical titania particles and dense structures where the titania shell is surrounding a carbon core. Although the synthesized titania hollow spheres exhibited a similar photoelectrochemical behavior and optical properties than commercial P25, they showed a better photocatalytic response towards phenol photo-oxidation in terms of pollutant mineralization. This behavior cannot be explained in terms of the crystallinity (found to be higher for P25) and has been attributed to both confinement effects in the mesoporosity of these catalysts as well as to the spherical morphology of titania particles. The spherical arrangement of the titania surface would favor the fast motion of the charge carriers and minimize recombination processes. On the other hand, no clear contribution of the carbon phase to the enhanced photocatalytic response, since quite similar performance is observed for the hollow spheres and the core/shell composite. However, separation and filtration of the catalysts become easier for the carbon/titania composite, thereby improving the so-called practical efficiency. Leticia F. Velasco, Marta Haro, Julien Parmentier, Roger Gadiou, Cathie Vix-Guterl, and Conchi O. Ania Copyright © 2013 Leticia F. Velasco et al. All rights reserved. Wed, 10 Oct 2012 09:57:38 +0000 http://www.hindawi.com/journals/catalysts/2013/364275/ The study of photocatalytic degradation of phenol was exploited with nano-ZnO as immobilized photocatalysts in a laboratory scale photocatalytic reactor. The photocatalytic degradation mechanism and kinetics of phenol in water were studied using the solid-phase microextraction (SPME) technique. Based on optimized headspace SPME conditions, phenol in water was first extracted by the fibre, which was subsequently inserted into an aqueous system with immobilized photocatalysts (nano-ZnO) exposed to an irradiation source (i.e., ultraviolet A (UVA) lamps). After different irradiation times (5–80 min), four main intermediates of photocatalytic degradation generated on the fibre were determined by GC-MS. Y. Tao, Z. L. Cheng, K. E. Ting, and X. J. Yin Copyright © 2013 Y. Tao et al. All rights reserved.