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 strategy to develop highly-active and stable electrocatalysts for CO2RR.