Reactions of acetic acid on UO2(111) single crystal surfaces

The reactions of acetic acid have been investigated on the (111) surface of uranium dioxide single crystals, which was characterized by low energy ele ctron diffraction and Auger electron spectroscopy. Temperature programmed d esorption (TPD) of this molecule displays a rich chemistry on both the stoi chiometric and electron beam sputtered surfaces. Acetic acid-TPD on a stoic hiometric surface yields ketene (dehydration) as the main product, plus ace taldehyde as the minor product. On an electron beam sputtered surface, two additional association products were observed-butene and crotonaldehyde. Th e carbon yield of ketene on the stoichiometric surface was comparable to th at of CeO2(111) and TiO2(001), higher than that of ZnO(0001) and Cu2O(100), but lower than that of MgO(100). This investigation has shown the ability of UO2(111) surfaces to dehydrate, reduce, and reductively couple organic m olecules. (C) 2000 American Vacuum Society: [S0734-2101(00)04204-4].