Self-supported sheet-like Bi2O3 electrodes for co-electrolysis of CO2 conversion and Cl- upgrading

The renewable electricity-driven CO2 electroreduction reaction (CO2RR) provides an alternative approach to producing carbon chemicals that are typically derived from fossil fuels. However, conventional CO2RR entail coupling the cathodic CO2 reduction with the anodic oxygen evolution reaction (OER), resulting in approximately 90 % of the electricity input being con-sumed by the OER. In this study, Cl- oxidation reaction (ClOR) was implemented as a replacement for OER, and a high -performance, self-supported, nanosheet-like Bi2O3 catalyst was designed through a simple electrodeposition process. As a result, a low-cost, durable, and energy-efficient electrolysis system was successfully developed for the conversion of CO2 and Cl- into dual value-added products. The CO2RR-ClOR system demonstrated high faradaic efficiencies for the production of formate (-98.7 %) and hypochlorite (-98 %) at the cathode potential of - 1.01 V vs. reversible hydrogen electrode (RHE), and exhibited the highest energy efficiency of 54 % at - 0.81 V vs. RHE, which was 3.3 times greater than that of the conventional CO2RR-OER system. This study may serve as a viable framework for the development of costeffective and sustainable CO2 electroreduction processes.