Transition metal oxides catalysis

Oxidation catalysts are either metals that chemisorb oxygen readily, such as platinum or silver, or transition metal oxides that are able to give and take oxygen by reason of their having several possible oxidation states. Ethylene oxide is formed with silver, ammonia is oxidized with platinum, and silver or copper in the form of metal screens catalyze the oxidation of methanol to formaldehyde. Cobalt catalysis is used in the following oxidations butane to acetic acid and to butyl-hydroperoxide, cyclohexane to cyclohexylperoxide, acetaldehyde to acetic acid and toluene to benzoic acid. PdCh-CuCb is used for many liquid-phase oxidations and V9O5 combinations for many vapor-phase oxidations. 

Volume 45 Transition Metal Oxides. Surface Chemistry and Catalysis by H.H. Kung... 

H.H.Kung, Transition Metal Oxides Surface Chemistry and Catalysis,Stud.Surf.Sci. Catal., bl.45, Elsevier, Amsterdam, 1990. 

W. M. H. Sachtler, G. J. H. Dorgelo, J. Fahrenfort, and R. J. H. Voorhoeve, Correlations between catalytic and thermodynamic parameters of transition metal oxides, Proceedings 4th Int. Congress Catalysis, Moscow, 1968 (Akad. Kiado, Budapest) vol 1971, pp. 454-465. 

Application of transmission electron microscopy (TEM) techniques on heterogeneous catalysis covers a wide range of solid catalysts, including supported metal particles, transition metal oxides, zeolites and carbon nanotubes and nanofibers etc. 

Kung, H.H., "Transition Metal Oxides Surface Chemistry and Catalysis," Elsevier Science Publ., Amsterdam, 1989. 

A fundamental problem in characterizing metal surfaces in oxidation catalysis is that, as with transition metal oxides, the chemistry of the surface is shaped by the reaction conditions. Margolis has taken the plausible position that most metal surfaces in oxygen are covered with oxygen and behave like metal oxides (13, 14). This is true even of platinum, a classical example of a metal catalyst, and here again predictions from bulk thermodynamics are unreliable with respect to the surface. 

Because of their importance in the mechanism of oxidation reactions, much attention has been paid to the kinds of oxygen species present on the surface of these catalysts. A general review concerning oxygen in catalysis by transition metal oxides has recently been presented by Bielanski and Haber.5 In this section the most important results of the main methods of investigation are reviewed. 

Mesoporous materials with a transition metal oxide framework have immense potential for applications in catalysis, photocatalysis, sensors, and electrode materials because of their characteristic catalytic, optical, and electronic properties. However, for some applications, this potential can only be maximized in the highly crystalline... 

Since mesoporous materials contain pores from 2 nm upwards, these materials are not restricted to the catalysis of small molecules only, as is the case for zeolites. Therefore, mesoporous materials have great potential in catalytic/separation technology applications in the fine chemical and pharmaceutical industries. The first mesoporous materials were pure silicates and aluminosilicates. More recently, the addition of key metallic or molecular species into or onto the siliceous mesoporous framework, and the synthesis of various other mesoporous transition metal oxide materials, has extended their applications to very diverse areas of technology. Potential uses for mesoporous smart materials in sensors, solar cells, nanoelectrodes, optical devices, batteries, fuel cells and electrochromic devices, amongst other applications, have been suggested in the literature.11 51... 

In heterogeneous catalysis, transition metal nanoparticles are supported on different substrates and are utilized as catalysts for different reactions [57], such as hydrogenations and enantioselective synthesis of organic compounds [58], oxidations and epoxidations [59], and reduction and decomposition [57],... 

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