Constructing a Channel to Regulate the Electron-Transfer Behavior of CO Adsorption and Light-Driven CO Reduction by H 2 over CuO-ZnO.

Photocatalytic conversions of C1 molecules under mild conditions have been widely researched in many fields. Adsorption of reactants at a catalyst surface is an indispensable process for C1 conversion and thus it might play a key role in reaction behavior. Herein, for a ZnO sample without photocatalytic activity for CO + H 2 reduction, CuO is introduced into ZnO to regulate the adsorption behavior of CO on the CuO-ZnO surface and then to drive the reduction of CO by H 2 under UV irradiation. The results of gas sensitivity tests and various in situ characterization methods are as expected. Specifically, surface zinc vacancies and Cu 2+ sites at the interface of ZnO and CuO cooperate to construct a special electron-transfer channel (Zn-O-Cu-O) for CO adsorption [CO (ads)]. A new linear adsorption mode of CO at Cu 2+ sites occurs, and this successfully changes the electron-transfer behavior of CO (ads) from donating electrons (to ZnO) to accepting electrons (from CuO-ZnO) via electron-transfer channels and d-electrons of Cu 2+ matching. Then, CO molecules are reduced by H 2 under UV irradiation. The strategy here provides an insight into the design of highly effective catalysts as well as an in-depth understanding of the mechanism of C1 photocatalytic conversion.