Status of Structure Sensitive Reactions

Much has been written about structure sensitivity, and a detailed review of ths subject will appear shortly.306 What follows, therefore, is only a brief survey of some more recent ideas on this subject, which we shall try to relate to particle size effects. 

The influence of the support on the activity of catalysts for the CO/H2 reaction, especially in the so-called Strong Metal-Support Interaction systems needs to be considered. Silica is normally considered a relatively 

Coenen and co-workers311,312 note also that under steady state conditions only a small fraction of the Ni surface is active ( 1%). They speculate that large crystals have higher activities because they contain fewer ridges and 

A final interesting observation both for Ni311 312 and Ru310 catalysts, is that small metal particles disappear during the course of the CO/H2 reaction. This effect has been attributed to the exothermicity of the reaction. The release of heat into a small particle could raise its temperature well above the reaction temperature. This in turn could result in major reconstruction of the particle to give a surface structure which best suited the adsorption of these particular reactants. How this would be reflected in terms of structure sensitivity is an interesting question. 

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