Angle-resolved XPS investigations of the interaction between O2 and Mo2C/Mo(1Â 0Â 0)

O2 adsorbs dissociatively on Mo2C/Mo(1 0 0) at room temperature. Oxidation of the carbide at 800 K results in the partial removal of carbon and leads to sub-surface O migration, accompanied by the appearance of highly oxidized Mo states. Raising the O2 adsorption temperature to 900 K decreased the carbon content further, without affecting the amount and the distribution of adsorbed O. Performing the oxidation at 1000 K led to an even more effective removal of carbon, but the oxygen content of the surface region was also reduced.