Chemisorption studies on Cs/Cu(110): Model studies of cesium promoters on copper-based catalysts

The adsorption of CO, CO2, and H2 O, the coadsorption of oxygen and H2 O, and the coadsorption of CO and surface hydroxyl (OH/sub a/)= on clean and cesium-covered Cu(110) surfaces have been studied with thermal desorption mass spectroscopy, x-ray photoelectron spectroscopy, Auger electron spectroscopy, and work function measurements. We review here results which show that the presence of preadsorbed cesium dramatically affects the adsorption behavior and surface chemistry of CO, CO2, and H2 O on Cu(110). We also present new results which show that surface formate (HCOO/sub a/) is not produced in any observable amount upon heating coadsorbed CO/sub a/ and OH/sub a/ on clean or Cs-dosed Cu(110). The implication of these results to Cs promotion of the catalytic water--gas shift and methanol synthesis reactions over Cu will be discussed