Unraveling oxygen vacancy-driven catalytic selectivity and hot electron generation on heterointerfaces using...

Modulating the physicochemical properties of oxides is crucial to achieve efficient and desirable reactions in heterogeneous catalysis. However, their catalytic role is not clearly identified because unevenly distributed interfaces and close conjugation with metal catalysts may hinder distinguishing their contribution in complex random structures. Here, we demonstrate a model platform composed of well-aligned CeO_x nanowire arrays on Pt catalysts to observe their catalytic role systematically. Independently modulating the crystallinity and oxygen vacancy concentration of oxide nanowires, while preserving heterogeneous interfaces, enables quantitative analysis of their individual effects on partial oxidation selectivity, resulting in hot electron generation during methanol oxidation reactions. CeO_x treated with vacuum annealing on Pt exhibits 1.47- and 2.12-times higher selectivity to methyl formate and chemicurrent yield than CeO_x without annealing on Pt. Density-functional theory calculations reveal that the promoted charge transfer from the electron-accumulated interface driven by oxygen vacancy acts as a key parameter in enhancing selectivity.