CO AND RESIDUAL H ADSORPTION ON CU ZNO(10(1)OVER-BAR-0)/

The adsorption of CO on clean ZnO(<10(1)over bar 0>) and on Cu deposit ed ZnO(<10(1)over bar 0>) surfaces at room temperature and at 200 K wa s studied by Auger electron spectroscopy, low-energy electron diffract ion and high-resolution electron energy-loss spectroscopy (HREELS). Cu deposited on an oxygen-depleted ZnO surface favors formation of OH an d CHx groups during CO exposure due to adsorption of residual hydrogen . Observed losses of OH and CHx may perhaps act as possible precursors or intermediates on the Cu/ZnO catalyst surface. With precooled Cu/Zn O(<10(1)over bar 0>) exposed to 100 Pa CO, a top-positioned CO vibrati onal feature was found by HREELS.