Interaction of NO with the O-rich RuO2(1Â 1Â 0) surface at 300Â K

The interaction of NO with the O-rich RuO2(1 1 0) surface, exposing coordinatively unsaturated O-bridge, O-cus, and Ru-cus atoms, was studied at 300 K by thermal desorption spectroscopy (TDS) and high-resolution electron energy-loss spectroscopy (HREELS). The conclusions are validated by isotope substitution experiments with 18O. During exposure to NO an O···N-O surface group (NO2-cus) is formed with O-cus. Additionally, a smaller number of empty Ru-cus sites are filled by NO-cus. If one warms the sample to 400 K, NO2-cus does not desorb but decomposes into O and NO again, the latter being either released into gas phase or adsorbed as NO-cus. With O-bridge such a surface group is not stable at 300 K. Our experiments further prove that O-cus is more reactive than O-bridge.