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Alkali-promoted metal oxide catalysts applications

This simple concept has already found some practical applications The idea to use supported alkali-promoted noble metal catalysts for NO reduction,3,4 even under mildly oxidizing conditions,5 came as a direct consequence of electrochemical promotion studies utilizing both YSZ (Chapter 8) and p"-Al203 (Chapter 9), which showed clearly the electrophi-licity of the NO reduction reaction even in presence of coadsorbed O. This dictated the use of a judiciously chosen alkali promoter coverage to enhance both the rate and selectivity under realistic operating conditions on conventional supported catalysts. [Pg.516]

In summary, alkali promotion of supported metal catalysts is an interesting subject that does have important technological implications in those cases where the presence of alkali has a pivotal influence on the surface chemistry of the metal phase. Fundamental studies of such systems are certainly justified. However, we should maintain a sense of proportion. Alkalis find relatively limited use as promoters in practical catalysis—indeed in some cases they act as powerful poisons. And we should not lose sight of the fact that what is actually present at the surface of the working catalyst is not an alkali metal, but some kind of alkali surface compound. This chapter deals with the application of alkali promoters to catalysis by metals, as opposed to catalysis by oxides, and, in particular, the technique of electrochemical promotion (EP), which enables us to address some pertinent issues. [Pg.604]

This section reports a series of examples of application of the cluster model approach to problems in chemisorption and catalysis. The first examples concern rather simple surface science systems such as the interaction of CO on metallic and bimetallic surfaces. The mechanism of H2 dissociation on bimetallic PdCu catalysts is discussed to illustrate the cluster model approach to a simple catalytic system. Next, we show how the cluster model can be used to gain insight into the understanding of promotion in catalysis using the activation of CO2 promoted by alkali metals as a key example. The oxidation of methanol to formaldehyde and the catalytic coupling of prop)me to benzene on copper surfaces constitute examples of more complex catalytic reactions. [Pg.160]

Lambert reviews the role of alkali additives on metal films and nanoparticles in electrochemical and chemical behavior modihcations. Metal-support interactions is the subject of the chapter by Arico and coauthors for applications in low temperature fuel cell electrocatalysts, and Haruta and Tsubota look at the structure and size effect of supported noble metal catalysts in low temperature CO oxidation. Promotion of catalytic activity and the importance of spillover are discussed by Vayenas and coworkers in a very interesting chapter, followed by Verykios s examination of support effects and catalytic performance of nanoparticles. In situ infrared spectroscopy studies of platinum group metals at the electrode-electrolyte interface are reviewed by Sun. Watanabe discusses the design of electrocatalysts for fuel cells, and Coq and Figueras address the question of particle size and support effects on catalytic properties of metallic and bimetallic catalysts. [Pg.4]


See other pages where Alkali-promoted metal oxide catalysts applications is mentioned: [Pg.295]    [Pg.414]    [Pg.246]    [Pg.260]    [Pg.286]    [Pg.597]    [Pg.162]    [Pg.113]   
See also in sourсe #XX -- [ Pg.340 ]




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Alkali application

Alkali catalysts

Alkali metals oxides

Alkali oxides

Alkali promoters

Alkali-promoted

Alkali-promoted metal oxide catalysts

Application oxidation

Application oxide

Applications metal oxide catalysts

Catalyst alkali metal

Catalyst promotion

Catalysts metal oxidation

Metal Oxides applications

Metal applications

Metal oxide catalysts

Metal oxides, catalysts oxidation

Oxidation catalyst application

Oxidized, applications

Promoted catalysts

Promoter alkali metal

Promoter, catalyst

Promoters oxidation

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