In situ transformation of bismuth metal–organic frameworks for efficient selective electroreduction of CO2 to formate

Abstract

The bismuth-based materials are proven as valid electrocatalysts for electrochemical conversion of carbon dioxide (CO₂) into formate (HCOO⁻). Herein, we discover that HCO₃⁻ can destroy the Bi–O bonds of the bismuth–carboxylate MOF to achieve in situ transformation into Bi₂O₂CO₃ (MOF-derived Bi₂O₂CO₃), which is merely explored yet. MOF-derived Bi₂O₂CO₃ shows superior electrocatalytic performance in a broad range of potentials and demonstrates a formate faradaic efficiency (FE_HCOO⁻) of 96.1% as well as an outstanding durability in 48 h with a current density about 10 mA cm⁻² at a potential of −0.669 V vs. RHE. And compared with the structurally similar bismuth oxyhalides, MOF-derived Bi₂O₂CO₃ possesses higher stability and lower CO₂ concentration-dependence during CO₂ reduction. Furthermore, this work puts a new strategy forward to achieve in situ MOF transformation and to comprehend the stability of electrocatalysts.