Metal oxides heterojunction derived Bi-In hybrid electrocatalyst for robust electroreduction of CO2 to formate

Electrochemical reduction of Bi-based metal oxides is regarded as an effective strategy to rationally design advanced electrocatalysts for electrochemical CO2 reduction reaction (CO2RR). Realizing high selectivity at high current density is important for formate production, but remains challenging. Herein, the BiIn hybrid electrocatalyst, deriving from the Bi2O3/In2O3 heterojunction (MOD-BiIn), shows excellent catalytic performance for CO2RR. The Faradaic efficiency of formate (FEHCOO-) can be realized over 90% at a wide potential window from-0.4 to-1.4 V vs. RHE, while the partial current density of formate (jHCOO -) reaches about 136.7 mA cm-2 at-1.4 V in flow cell without IR-compensation. In addition, the MOD-BiIn exhibits superior stability with high selectivity of formate at 100 mA cm-2. Systematic characterizations prove the optimized catalytic sites and interface charge transfer of MOD-BiIn, while theoretical calculation confirms that the hybrid structure with dual Bi/In metal sites contribute to the optimal free energy of *H and *OCHO intermediates on MOD-BiIn surface, thus accelerating the formation and desorption step of *HCOOH to final formate production. Our work provides a facile and useful strat-egy to develop highly-active and stable electrocatalysts for CO2RR.(c) 2023 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

This study demonstrates the successful synthesis of Bi2O3/In2O3 hybrid catalyst, which exhibits high selectivity for formate production in electrochemical CO2 reduction reaction at high current density. The Faradaic efficiency of formate can reach over 90% in a wide potential window from -0.4 to -1.4 V vs. RHE. The partial current density of formate reaches about 136.7 mA cm-2 at -1.4 V in a flow cell without IR-compensation. The BiIn hybrid catalyst demonstrates superior stability and selectivity, attributed to its optimized catalytic sites and interface charge transfer.