A view of surface science since 1960: Oxygen states at metal surfaces

The article describes how the application of experimental methods developed over the last 40 years (work function, photoemission, photoelectron spectroscopy and scanning tunnelling microscopy) enables our understanding of oxygen chemisorption to progress in a step-wise manner, with STM providing the ultimate atom-resolved evidence for the dynamics involved. Different oxygen states exhibit distinct reactivities and provide a stimulus for the design of catalysts with specific activities in oxidation catalysis. There is also evidence accruing that disordered oxygen states are in general more active in dehydrogenation reactions than the ordered states, with for example ammonia being ‘oxidised’ to nitrogen adatoms at Cu(1 1 0) at cryogenic temperatures.