Bifunctional Oxygen‐Defect Bismuth Catalyst toward Concerted Production of H2O2 with over 150% Cell Faradaic Efficiency in Continuously Flowing Paired‐Electrosynthesis System

Abstract

AbstractThe electrosynthesis of hydrogen peroxide (H2O2) from O2 or H2O via the two‐electron (2e−) oxygen reduction (2e− ORR) or water oxidation (2e− WOR) reaction provides a green and sustainable alternative to the traditional anthraquinone process. Herein, a paired‐electrosynthesis tactic is reported for concerted H2O2 production at a high rate by coupling the 2e− ORR and 2e− WOR, in which the bifunctional oxygen‐vacancy‐enriched Bi2O3 nanorods (Ov‐Bi2O3‐EO), obtained through electrochemically oxidative reconstruction of Bi‐based metal–organic framework (Bi‐MOF) nanorod precursor, are used as both efficient anodic and cathodic electrocatalysts, achieving concurrent H2O2 production at both electrodes with high Faradaic efficiencies. Specifically, the coupled 2e− ORR//2e− WOR electrolysis system based on such distinctive oxygen‐defect Bi catalyst displays excellent performance for the paired‐electrosynthesis of H2O2, delivering a remarkable cell Faradaic efficiency of 154.8% and an ultrahigh H2O2 production rate of 4.3 mmol h−1 cm−2. Experiments combined with theoretical analysis reveal the crucial role of oxygen vacancies in optimizing the adsorption of intermediates associated with the selective two‐electron reaction pathways, thereby improving the activity and selectivity of the 2e− reaction processes at both electrodes. This work establishes a new paradigm for developing advanced electrocatalysts and designing novel paired‐electrolysis systems for scalable and sustainable H2O2 electrosynthesis.