MONITORING SURFACE-REACTIONS WITH SCANNING-TUNNELING-MICROSCOPY - CO OXIDATION ON P(2X1)-O PRE-COVERED CU(11O) AT 400-K

Scanning tunneling microscopy (STM) is used to study the oxidation of CO on O pre-covered Cu(110) in the steady state at 400 K at the atomic level. There is a strong preference for CO to react with oxygen along the p(2 X 1) oxygen rows. The reaction appears to occur initially at the outer edge of an oxygen island, creating defects in the overlayer structure. Once created, oxygen overlayer defects are more reactive than non-defect sites and play a dominant role in sustaining the reaction. Copper atoms that make-up the p(2 X 1) oxygen overlayer structure add to terrace edges after oxygen supply is exhausted and do not form small Cu islands that could eventually lead to surface roughening.