The Structure and Catalytic Properties of Palladium-Silver and Palladium-Gold Alloys

The great differences between the catalytic activities of the Group VIII and the Group IB metals have attracted much attention, especially over the last 25 years, and explanations of these differences have been sought through studying the manner of activity variation in alloys formed between suitable pairs of metals. Selection of suitable alloy systems has presented difficulties. Most work has naturally been done on systems exhibiting a continuous range of solid solution, and hence Pt-Au and Pt-Ag alloys, both of which have miscibility gaps, have not been widely studied. Much work has been done on Ni-Cu alloys, but recent results have demonstrated the presence of phase separation in this system, and this has called into question the interpretation of the earlier work. The Pd-Ag and Pd-Au systems appear to have complete miscibility, and have consequently been much studied: it is to them that this review is directed.