Factors determining the selectivity of multimetallic catalysts

The results relevant for the theory of catalysis and of interest for this Conference, obtained with model alloys (active metal with an inactive one) are reviewed first. It is argued that of the two effects of alloying—ensemble size effect and the electronic (ligand) effect— the first one is more important. Recent results obtained with Pt/Re alloys (two active metals) are briefly summarized and a conclusion is made that the results can be rationalized by ideas reviewed in the first part of this paper.