Boosting and stabilizing the electrocatalytic reduction of carbon dioxide on Bi2O2CO3 via surface modification with p-aminobenzoic acid

In the realm of electrocatalytic CO2 reduction (ECR) reactions, the challenges of instability and self-reducibility present significant obstacles to the practical application of bismuth oxide-based catalysts. Herein, Bi2O3 pre-catalyst was synthesized and surface-modified with 4-aminobenzoic acid (PABA). Theoretical studies confirmed that PABA was effectively grafted through oxygen vacancies on the Bi2O3 surface, leading to electronic rearrangement. PABA efficiently prevented surface Bi3+ on Bi2O3 from self-reducing to Bi0 during the ECR reaction. The Bi2O3PABA pre-catalyst transformed into the active Bi2O2CO3PABA ECR catalyst via electrolyte mediation. A Faraday efficiency of 98.6 % for formate was achieved at −1.1 V vs. RHE, with a wide potential window of 800 mV. The current density reached 210 mA cm–2 in a 2×2 cm2 flow cell system. Theoretical calculations illustrate that PABA facilitates stabilizing the *OCHO intermediate, diminishing the adsorption barrier. These results may provide valuable insights for designing highly selective ECR catalysts through interface engineering.