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

A well-defined In 2 O 3 /InN heterojunction was developed for the electrocatalytic CO 2 reduction reaction to formate. The O-N interaction at the interface of In 2 O 3 /InN heterojunction promotes the charge transfer to activate CO 2 molecules, lower the Gibbs free energy for *HCOO formation and thus results in unprecedented high Faradaic efficiency (95.7% at −1.48 V vs. RHE) and outstanding stability. [Display omitted] • Pure In 2 O 3 or In 2 O 3 /InN heterostructure were obtained under different atmosphere. • The In 2 O 3 /InN catalyst exhibits enhanced FE formate (>95%) from −1.37 to −1.59 V. • The In 2 O 3 /InN heterojunction exhibits almost no degradation of performance after 30 h. • The O-N interaction at the interface of In 2 O 3 /InN heterojunction promotes charge transfer. • In situ ATR-SEIRAS and DFT were performed to reveal the electrocatalytic mechanism. Electrocatalytic reduction of CO 2 into value-added chemicals and fuels is of intensive urgence and importance to relieve the growing CO 2 emission and achieve the carbon neutrality. Herein, an In 2 O 3 /InN heterojunction was constructed and firstly utilized in electrocatalytic CO 2 reduction reaction (CO 2 RR) 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 In 2 O 3 and InN could provide a charge transfer channel and lead to electron enrichment on the surface of InN, promoting the activation of CO 2 molecules, lowering the Gibbs free energy for the formation of *HCOO intermediate and strengthening the binding with *HCOO during CO 2 RR. This work provides a fundamental understanding of the interaction at In-based heterostructure interface for highly selective CO 2 reduction to formate and offers a universal route for the design of other type metal oxide/nitride heterostructures for various catalytic applications. [ABSTRACT FROM AUTHOR]