Designing Bi‐In₂O₃ Nanoflower Catalysts for Enhanced Performance of Electrochemical CO₂ Reduction to Formate

Abstract Electrochemical CO₂ reduction (ECO₂RR) is capable of converting CO₂ into a wide range of value‐added products under relatively mild conditions. Electrocatalyst with high selectivity and activity is crucial for high efficient ECO₂RR. Herein, Bi‐In₂O₃ nanoflower catalysts with different metal ratios synthesized by wet chemical method are used for ECO₂RR to produce formate. The results indicate that the hydrogen evolution activity of the Bi‐In₂O₃ catalysts during ECO₂RR is suppressed at a low level and the activity and selectivity of formate production is related to the ratio of Bi to In content in the catalysts. The optimized Bi‐In₂O₃ catalyst with the ratio of Bi₆In₉₄ can achieve a high formate Faradaic efficiency (FE_formate) over 80 % under a wide potential range from −0.7 V to −1.2 V vs. RHE, with the maximum value of 88.1 % at −0.7 V vs. RHE. Meanwhile, the highest formate partial current density reaches 47.7 mA cm⁻² at −1.2 V vs. RHE and the current density and Faradaic efficiency remain stable during the 10 h stability test. The enhanced formate formation on Bi‐In₂O₃ NF can be attributed to the synergistic effect between Bi and In according to the characterizations of the Bi‐In₂O₃ NF.