http://www1.udel.edu/chem/polenova/PDF/Polyoxometalates/POMs_Catalysis_NMR_ChemRev1998.pdf

Catalysis by Heteropoly Acids and Multicomponent Polyoxometalates in Liquid-Phase Reactions

In the paragraph following eq 28, the average bond valence was incorrectly referred to as V/R. It has been corrected to V/N. The paper originally posted to the web on September 3, 2009, and was reposted on September 24, 2009.

http://pubs.acs.org/doi/pdf/10.1021/cr900053k

Recent developments in the methods and applications of the bond valence model.

Catalysis by heteropoly acids (HPAs) and related compounds is a field of growing importance, attracting increasing attention worldwide, in which many new and exciting developments are taking place in both research and technology [1–111, HPAs are polyoxometalates incorporating anions (heteropolyanions) having metal-oxygen octahedra as the basic structural units [ll-141. Among a wide variety of HPAs those belonging to the so-called Keggin series are the most importance for catalysis. They include heteropolyanions (HPANs)

Heteropoly Acids and Related Compounds as Catalysts for Fine Chemical Synthesis

Concern over the economics of accessing fossil fuel reserves, and widespread acceptance of the anthropogenic origin of rising CO2 emissions and associated climate change from combusting such carbon sources, is driving academic and commercial research into new routes to sustainable fuels to meet the demands of a rapidly rising global population. Here we discuss catalytic esterification and transesterification solutions to the clean synthesis of biodiesel, the most readily implemented and low cost, alternative source of transportation fuels to meet future societal demands.

/pdf/heterogeneous-catalysis-for-sustainable-biodiesel-production-wruq11o683.pdf

Heterogeneous catalysis for sustainable biodiesel production via esterification and transesterification

Atomically thin molybdenum disulfide (MoS2) layers have attracted great interest due to their direct-gap property and potential applications in optoelectronics and energy harvesting. Meanwhile, they are extremely bendable, promising for applications in flexible electronics. However, the synthetic approach to obtain large-area MoS2 atomic thin layers is still lacking. Here we report that wafer-scale MoS2 thin layers can be obtained using MoO3 thin films as a starting material followed by a two-step thermal process, reduction of MoO3 at 500 °C in hydrogen and sulfurization at 1000 °C in the presence of sulfur. Spectroscopic, optical and electrical characterizations reveal that these films are polycrystalline and with semiconductor properties. The obtained MoS2 films are uniform in thickness and easily transferable to arbitrary substrates, which make such films suitable for flexible electronics or optoelectronics.

/pdf/wafer-scale-mos2-thin-layers-prepared-by-moo3-sulfurization-164apdnl1t.pdf

Wafer-Scale MoS2 Thin Layers Prepared by MoO3 Sulfurization

Catalytic properties of MoO3 revisited

Microcalorimetric study of sorption of water and ethanol in zeolites 3A and 5A

The authors report results from use of aluminium-free zeolytic catalysts, loaded with gallium to different levels, for the conversion of methanol. Work was done for temperatures up to 400{degrees}C. They find a strong dependence and selectivity for conversion to dimethyl ether with gallium content between 150 and 300{degrees}C. At higher temperatures they observe enhanced conversion of alkanes into aromatics. The graded gallium content allowed the authors to distinguish the gallium activity from that due to any trace aluminium impurities.

The role of gallium in the catalytic activity of zeolite [Si,Ga]-ZSM-5 for methanol conversion

The topotactic mechanism for the reduction of MoO3 to MoO2 has been well-supported by experiments, though the detection of Mo4O11 during the process has been a challenge to the notion of direct con...

Mechanisms of reduction of MoO3 to MoO2 reconciled

Present research concentrates on the role of alkali modifiers (Li, Na, K, Cs) in activity of 2%Pd/Al2O3 catalyst for 2-ethyl-9,10-anthraquinone (eAQ) hydrogenation. The catalysts with various content of alkali modifier (Me/Pd molar ratio ranges from 0.5 up to 4, Me-alkali metal) were prepared by impregnation of pre-reduced 2%Pd/Al2O3 catalyst with appropriate alkali metal carbonates. The XPS, EDS and TEM measurements show that alkali promoters are introduced into alumina matrix. The microcalorimertic experiments of CO adsorption prove the interaction of CO with catalysts leading to stronger bonding of carbon monoxide by alkali doped catalysts. The presence of alkali promoters in Pd/Al2O3 catalyst plays an essential role in the whole eAQ hydrogenation process. The nature of alkali promoter and its content (Me/Pd atomic ratio) in catalyst are of importance. As the alkalinity of promoter increases going from Li to Cs all the effects caused by their presence become stronger. In the presence of alkali doped catalysts the content of 2-ethyloxoanthrone (OXO, isomer of 2-ethyl-9,10-anthrahydroquinone) formed is higher than that on un-doped 2%Pd/Al2O3. On the other hand, reactions in the “deep hydrogenation” stage comprising the formation of 2-ethyl-5,6,7,8-tetrahydro-9,10-anthraquinone (H4eAQ) and the transformation of OXO to 2-ethylanthrone and other degradation products are remarkably inhibited. In particular, the formation of 2-ethylanthrone via hydrogenolysis of OXO isomer is strongly suppressed. The Cs-doped catalyst exhibits the highest activity to OXO among all the catalysts tested whereas the ability of Cs-doped catalysts to the formation of anthrone is most effectively inhibited. The role of alkali modifiers is considered to be associated with stronger interactions between the catalyst and quinone reagents, and in particular OXO isomer. Moreover, in the reagent adsorption the centres of support nearby the palladium particles may also participate by affecting the mode of reagents adsorption.

E. Lalik

Papers

Catalytic properties of MoO3 revisited

Microcalorimetric study of sorption of water and ethanol in zeolites 3A and 5A

The role of gallium in the catalytic activity of zeolite [Si,Ga]-ZSM-5 for methanol conversion

Mechanisms of reduction of MoO3 to MoO2 reconciled

The role of alkali modifiers (Li, Na, K, Cs) in activity of 2%Pd/Al2O3 catalysts for 2-ethyl-9,10-anthraquione hydrogenation