Alkali-promoted Ni-Co-Mo catalysts supported on multiwalled carbon nanotubes (MWCNTs) were prepared using 9&#x2009;wt&#x25; K, 4.5&#x2009;wt&#x25; Co, and 15&#x2009;wt&#x25; Mo, whereas Ni content was varied from 0 to 6&#x2009;wt&#x25;. The catalysts were extensively characterized and studied for higher alcohols synthesis from synthesis gas. Alkali-promoted trimetallic catalyst with 3&#x2009;wt&#x25; Ni showed the highest total alcohols yield of 0.284&#x2009;gm/(gm of cat./h), ethanol selectivity of 20&#x25;, and higher alcohols selectivity of 32&#x25; at 330&#xb0;C and 9.0&#x2009;MPa using gas hourly space velocity (GHSV) of 3.8&#x2009;m3 (STP)/kg of catalyst/h and H2 to CO molar ratio of 1.25.

Venkateswara Rao Surisetty

Janusz Kozinski

Ajay Kumar Dalai

Novel Ni-Co-Mo-K Catalysts Supported on Multiwalled Carbon Nanotubes for Higher Alcohols Synthesis

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&#x2009;mg L&#x2212;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&#x2009;g L&#x2212;1 after 180&#x2009;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

Hosakere Doddarevanna Revanasiddappa

Photocatalytic Degradation of Acid Yellow 36 Using Zinc Oxide Photocatalyst in Aqueous Media

Decatungstodivanadogermanic acid (H6GeW10V2O40&#x000B7;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&#xb0;C. This catalyst is efficient not only for cyclic ketones, but also for cyclic &#x3b2;-diketones, &#x3b2;-diester, and &#x3b2;-diamide derivatives such as cyclohexanone, dimedone, and Meldrum's acid, or barbituric acid derivatives.

Srinivasa Rao Jetti

Divya Verma

Shubha Jain

Microwave-Assisted Synthesis of Spirofused Heterocycles Using Decatungstodivanadogermanic Heteropoly Acid as a Novel and Reusable Heterogeneous Catalyst under Solvent-Free Conditions

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

Giuseppe Vasapollo

New Porphyrin/Fe-Loaded TiO2 Composites as Heterogeneous Photo-Fenton Catalysts for the Efficient Degradation of 4-Nitrophenol

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

Swadeshmukul Santra

Morphology-Controlled Synthesis and Characterization of Magnetic Iron Oxide Nanocrystals and Their Potential Applications in Selective Oxidation of Alcohols and Olefins

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 <svg style="vertical-align:-0.20473pt;width:23.475px;" id="M1" height="16.1" version="1.1" viewBox="0 0 23.475 16.1" width="23.475" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
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</svg> 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.

Fr&#xe9;d&#xe9;ric Lefebvre

Eva Grinenval

Piotr Putaj

Methane Activation and Transformation on Polyoxometalates

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

Gulzhian I. Dzhardimalieva

Hybrid Polymer-Immobilized Nanosized Pd Catalysts for Hydrogenation Reaction Obtained via Frontal Polymerization

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

Conchi O. Ania

Tuning the Photocatalytic Activity and Optical Properties of Mesoporous TiO2 Spheres by a Carbon Scaffold

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&#x2013;80&#x2009;min), four main intermediates of photocatalytic degradation generated on the fibre were determined by GC-MS.

Y. Tao

Z. L. Cheng

K. E. Ting

X. J. Yin

Photocatalytic Degradation of Phenol Using a Nanocatalyst: The Mechanism and Kinetics

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Journal of Catalysts