Water-Activated Lattice Oxygen in FeO(111) Islands for Low-Temperature Oxidation of CO at Pt-FeO Interface

The role of water in low-temperature oxidation of CO catalyzed at metal oxide interfaces is of great interest. In this paper, we prepared (FeO)-O-16(111)/Pt(111) and (FeO)-O-18(111)/on Pt(111) inverse model catalysts with the same coverage of FeO(111) monolayer islands and comparatively studied (CO)-O-16 oxidation with O-18(2) or (D2O)-O-18 on (FeO)-O-16(111)/Pt(111) inverse model catalyst and (CO)-O-16 oxidation with O-16(2) or (D2O)-O-16 on (FeO)-O-18(111)/Pt(111) inverse model catalyst. Lattice oxygen in FeO does not participate into CO oxidation with O-2 but participates into CO oxidation with water via the mechanism of CO oxidation with hydroxyl groups formed by water dissociation at the FeO(111)-Pt interface. These results provide unambiguous experimental evidence for the unique role of water in activating surface lattice oxygen of oxides to oxidize CO at low temperatures, advancing the fundamental understandings of low-temperature CO oxidation involving hydroxyl groups catalyzed by metal-oxide interfaces.