Oxygen transient states in catalytic oxidation at metal surfaces

Mechanistic aspects of catalytic oxidation at metal surfaces have involved four distinct stages of investigation which, in chronological order, are: (a) oxygen chemisorption and surface reconstruction with evidence for discrete metal and oxygen states; (b) the reactivity of specific oxygen states in oxydehydrogenation reactions; (c) the chemistry under dynamic conditions with evidence for dioxygen–reactant complexes at low temperature; (d) atom resolved evidence from scanning tunnelling microscopy. We discuss how these studies draw attention to the advantages of dynamic studies in revealing individual steps in oxidation catalysis, the role of labile surface complexes in providing low energy pathways to products and their relevance to the theoretical calculations and experimental studies of Jerzy Haber and his colleagues.