Coadsorption of oxygen, gold and carbon monoxide on Ru(0Â 0Â 0Â 1) and CO2 formation: A thermal desorption study

The coadsorption of O, Au and CO and COa + Oa reaction is studied on Ru(0 0 0 1) using temperature programmed desorption, Auger electron spectroscopy, and low energy electron diffraction. CO/CO2 desorption is measured on surfaces with different oxygen coverages and varying concentrations of Au using isotopically labeled 13C18O. There is no CO2 formation from CO adsorbed on clean Ru(0 0 0 1) and O(2 × 1), but CO2 forms on CO covered RuOx surfaces. We have observed CO2 formation below room temperature on O(2 × 1) and RuOx surfaces covered by Au nanoparticles. The conversion from CO to CO2 is found to be the highest over submonolayer Au films supported on RuOx suggesting a synergistic effect between catalytic Au nanoparticles and RuO2 domains.