Interaction between Cu and Pt(111) in the reaction CO + O2 Modification by Cu sub-monolayers and cooperation between pure and Cu-modified Pt(111)

Sub-monolayers of Cu modify the characteristics of the CO + CO2 reaction on Pt(111), in particular (i) the bistability region where either dense CO or oxygen adsorption layers can form according to the direction of variation of the external parameters, and (ii) the progression velocity of the reaction front as observed by PEEM. In addition, a cooperation takes place between Pt modified by Cu sub-monolayers and pure Pt(111). This highlights two different roles of copper in modifying the kinetics of CO oxidation, namely (i) triggering the reaction and (ii) modifying the rate of reaction front propagation. In addition, a completely new effect occurring at the border between Cu-covered and pure Pt is reported.