By rational design of the FeO(111)/Pt(111) inverse model catalyst and the control experiments, we report for the first time direct experimental evidence for the interfacial COads + OHads reaction to produce CO2 at the Pt-oxide interface at low temperatures, providing deep insights into the reaction mechanism and active site of the important tow-temperature water-gas shift and preferential CO oxidation reactions catalyzed by Pt/oxide nanocatalysts at the molecular level.