Proton-Transfer-Connected Elementary Surface Reaction Network for Low-Temperature CO Oxidation Catalyzed by Metal-Oxide Nanocatalysts

Abstract

Low-temperature CO oxidation catalyzed by metal-oxide nanocatalysts is a hot topic, but the mechanism is strongly debated. Via controlled preparation of isotope-labeled surface adsorbates on an FeO(111)/Pt(111) inverse model catalyst, we herein demonstrate that elementary surface reactions for CO oxidation with similar activation energies exist both on the Pt surface and at the FeO-Pt interface when surface hydroxyl groups and water are present. Water and hydroxyl groups can enhance the dissociation probability of molecularly adsorbed O2 to produce oxygen adatoms. The proton transfer from surface hydroxyl groups to adjacent oxygen adatoms connects the elementary surface reactions on the Pt surface and at the FeO-Pt interface to constitute a surface reaction network. These results for the first time provide a view of the proton-transfer-connected elementary surface reaction network for the unanimous understanding of low-temperature CO oxidation catalyzed by metal-oxide nanocatalysts and reveal the dual roles of surface hydroxyl groups to promote CO oxidation and bridge various surface reaction pathways. (Figure Presented).