Oxygen Adsorption On C0-c 4x2 Ni lll

O2 adsorption on C0-c(4x2)/ /Ni(lll) was studied to examine the stability of the C0-c(4x2) layer upon oxygen exposure. These experiments indicated chat C0-c(4x2) on Ni(lll) reduced the 

Up Co an exposure of 30 L of oxygen at room temperature, the C0-c(4x2) LEED pattern was still clearly observed although the background intensity increased. Fig. 4.4 shows m/e — 29 ( CO) 

Oxygen surface coiiceiitiatlon of the Ni(lll) dosed with O2 calculated from AES spectra In percent ( ) versus O2 exposure In L. Shown In the figure also are oxygen surface concentrations of Ni(111) pre-covered with CO-c(4x2) prior to O2 exposure (O) and transfer into the auxiliary chamber ( ). The triangle Indicates the oxygen concentration alter a bare Nl(lll) was exposed Co electrochemical environment und then transferred back Co Che main chamber. 

Co 30 L of oxygen. Two points are worth noticing. One is that more than 75% of original CO molecules remained on the surface, based on the integrated areas of the CO peaks. The other is that the high temperature CO feature (due to the reaction between adsorbed oxygen and carbon diffused from the bulk) was not observed in the CO TPD spectrum. 

Although electron beams are known to damage CO and other adsorbates on a Ni(lll) surface, AES was used in a few 

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