Interfacial engineering of In2O3/InN heterostructure with promoted charge transfer for highly efficient CO2 reduction to formate

Electrocatalytic reduction of CO2 into value-added chemicals and fuels is of intensive urgence and importance to relieve the growing CO2 emission and achieve the carbon neutrality. Herein, an In2O3/InN heterojunction was constructed and firstly utilized in electrocatalytic CO2 reduction reaction (CO2RR) to formate with high Faradaic efficiency (95.7% at −1.48 V vs. RHE) and outstanding stability. The in-depth experimental analyses together with theoretical studies reveal that the O-N interaction at the interface between In2O3 and InN could provide a charge transfer channel and lead to electron enrichment on the surface of InN, promoting the activation of CO2 molecules, lowering the Gibbs free energy for the formation of *HCOO intermediate and strengthening the binding with *HCOO during CO2RR. This work provides a fundamental understanding of the interaction at In-based heterostructure interface for highly selective CO2 reduction to formate and offers a universal route for the design of other type metal oxide/nitride heterostructures for various catalytic applications.