Zn-In-O electrocatalysts with co-existing ZnO and In2O3 phases for efficient reduction of CO2 to formate through sacrificial mechanism

Electrochemical CO 2 reduction reaction (eCO 2 RR) is considered an efficient approach to produce value-added chemicals and fuels. In this paper, a series of MOF-derived composite catalysts with coexisting In 2 O 3 and ZnO are fabricated using a simple process for eCO 2 RR to produce formate. The Zn-In-O/800 catalyst achieves a formate Faradaic efficiency (FE HCOO− ) of 94.25 % at −1.16 V vs. RHE, which can maintain over 89 % after 30 h in a stability test. The electrochemical evidence and density functional theory analysis show that the strong interface effect between In 2 O 3 and ZnO can enhance the CO 2 adsorption and activation, and promote the conversion of CO 2 to formate. In addition, the ZnO phase can protect In 2 O 3 , as the main active site, from being reduced to a certain extent for a long time under negative potential, which ensures the high stability of the composite catalyst.