Interaction of NO with the stoichiometric RuO2(110) surface

The interaction of NO with the stoichiometric RUO2(110) surface, exposing coordinatively unsaturated Ru-cus and O-bridge atoms, was studied by thermal desorption spectroscopy (TDS) and high-resolution electron energy loss spectroscopy (HREELS). At low exposure (less than or equal to0.5 L) and 85 K, NO is adsorbed on-top of Ru-cus with its molecular axis perpendicular to the surface for the first two-thirds of the monolayer and slightly bent when the final third is adsorbed. After saturation of this state, NO reacts with O-bridge in forming an NO2-type surface species which decomposes again at 250 K. At higher exposure, a small amount of N2O-CUS is formed, presumably via an (NO)(2) dimer intermediate. In parallel, a low-temperature pathway for N-2 formation is observed, which leaves the surface instantaneously between 130 and 190 K.