Bimetallic Bi-In nanoparticles for efficient production of formate via electrocatalytic conversion of CO2

Electrocatalytic reduction of CO₂ to valuable chemicals can alleviate the energy crisis and reduce the greenhouse effect. Herein, bimetallic Bi_xIn_y (x, y is percentage composition) nanoparticles (NPs) were successfully prepared and utilized as electrocatalysts for electrochemical conversion of CO₂ to formate. By changing the Bi/In atom ratio and varying the amount of surfactant PVP and solvent DMF, the surface morphology of and the electronic structure of Bi_xIn_y catalysts can be optimized. The optimized Bi_88.77In_11.23 NPs were the most favorable for formate formation and the FE (Faradaic efficiency) of formate reached 94.29% at a potential of − 1.0 V (vs. RHE). The DFT calculations confirmed that the synergistic effect of bimetallic and dense nanoparticle structures promotes the adsorption of CO₂ molecules and major ^*OCHO intermediates at active sites, thus accelerating the reaction rate. The Bi_88.77In_11.23 NPs were further employed as cathode coupling oxygen evolution reaction to construct a two-electrode electrolysis system (CO₂RR‖OER). The whole electrolysis needed a low cell voltage of 3.4 V to deliver 10 mA/cm². This study will provide an efficient approach to enhance the activity and selectivity for CO₂RR by the synergistic effect of bimetal.