An Interfacial Mediator Interpretation of Noble Metal Electrocatalysis

Abstract

Electrocatalysis is of considerable interest in many areas, such as in energy conversion and storage, electroanalysis, water purification and electroless metal deposition, and some of the most active materials in this area are the noble metals and their oxides, for example platinum and ruthenium dioxide. It is widely accepted that (even in heterogeneous catalysis in general) there is a wide gap between theory and practice: most industrial catalysts are developed by repetitive testing techniques. It has been proposed by the author that the fundamental problem in this area is the fact that the active interfacial mediators in electrocatalysis, which are the adatoms and incipient hydrous oxide species, reside virtually outside the solid lattice and exhibit chemical – and especially redox – behaviour very different to that of well embedded surface species. There is an urgent need to develop and apply highly sensitive techniques to investigate the behaviour of such quite low coverage reactive surface/interfacial species.