The Influence of Preadsorbed Chlorine on the Adsorption of CO on Ni(110) Surface

The adsorption of CO on chlorine-predosed Ni（110） surface was studied by UPS, XPS, AES and work function measurements. For chlorine coverage of 0. 11ML, the frs level Of CO shifts to higher binding energy by 0. 2eV, while 5o level slightly moves to lower binding energy. The preadsorbed chlorine makes the O（ls） level of CO broaden and shift to higher binding energy. The presence of chlorine reduces the thermal stability of CO on the coadsorbed surface, indicating the weakend strength of CO-Ni bond. The displacement of preadsorbed CO by chlorine induces the decrease in work function. The mechanism of electronegative modification of chlorine on Ni（110） surface was discussed.