Electron-deficient ZnO induced by heterointerface engineering as the dominant active component to boost CO2-to-formate conversion

초록

Electrocatalytic CO2-to-formate conversion is considered an economically viable process. In general, Zn-based nanomaterials are well-known to be highly efficient electrocatalysts for the conversion of CO2 to CO, but seldom do they exhibit excellent selectivity toward formate. In this article, we demonstrate that a heterointerface catalyst ZnO/ZnSnO3 with nanosheet morphology shows enhanced selectivity with a maximum Faradaic efficiency (FE) of 86% at −0.9 V versus reversible hydrogen electrode and larger current density for the conversion of CO2 to formate than pristine ZnO and ZnSnO3. In particular, the FEs of the C1 products (CO + HCOO−) exceed 98% over the potential window. The experimental measurements combined with theoretical calculations revealed that the ZnO in ZnO/ZnSnO3 heterojunction delivers the valence electron depletion and accordingly optimizes Zn d-band center, which results in moderate Zn–O hybridization of HCOO* and weakened Zn–C hybridization of competing COOH*, thus greatly boosting the HCOOH generation. Our study highlights the importance of charge redistribution in catalysts on the selectivity of electrochemical CO2 reduction. © 2024 The Authors. Carbon Energy published by Wenzhou University and John Wiley & Sons Australia, Ltd.

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