Electrolytic Growth of Hybrid Bi/BiOCl Nanosheets for pH‐Universal Electrocatalytic CO ₂ Reduction Reaction

To address the challenge of achieving high activity for electrocatalytic CO₂ reduction reaction (eCO₂RR) to produce formic acid/formate in the pH-universal media, this study designs a self-supported electrode with evenly dispersed hybrid metallic bismuth (Bi) and bismuth hypochlorite (BiOCl) nanosheets (Bi/BiOCl NSs) by an electrolytic growth process. Under the negative potential, the Bi salts loaded on the gas diffusion layer is in situ-reduced to the sheet-like hybrid Bi/BiOCl nanostructures with abundant active heterojunction sites during the eCO₂RR process, significantly optimizing the adsorption and conversion pathways of CO₂. The obtained electrode enables efficient conversion of CO₂ to formic acid under strongly acidic media (pH = 1.3), and formate under alkaline (pH = 14)/neutral (pH = 8.6 and 6.2) electrolytes, with all the peak Faradaic efficiencies exceeding 90%. Additionally, the electrode can operate stably at a high current density of 100 mA cm^-2 for 8 hours in pH-universal media, demonstrating its excellent corrosion resistance and structural stability. This study provides new insights for the design of efficient catalysts for eCO₂RR in comprehensive environments.