Field-induced reactant enrichment enhances benzyl alcohol electrooxidation coupled with hydrogen evolution

Abstract

Electrochemical hydrogen evolution coupled with organic oxidation (EHCO) offers a promising route to improve the energy efficiency of water electrolysis by replacing the sluggish oxygen evolution reaction with value-added organic oxidation processes. However, the limited adsorption of organic reactants on the catalyst surface remains a key bottleneck, constraining the overall performance of EHCO systems. Herein, we report a field-induced enrichment strategy to enhance benzyl alcohol electrooxidation coupled with hydrogen evolution. A nanostructured cooperative catalyst composed of Au nanoparticles supported on copper oxide nanowires (Au/CuO NWs) delivers an impressive current density of 734 mA cm⁻² at 1.5 V vs. RHE, along with a benzyl alcohol oxidation rate of 4.74 mmol cm⁻² h⁻¹ and a 91% faradaic efficiency for benzoic acid production. The catalyst demonstrated excellent stability and sustained industrial-level current output (>300 mA cm⁻²) in a membrane-free flow electrolyser. Combined experimental and COMSOL simulation results reveal that the nanowire morphology induces stronger localised electric fields, promoting the interfacial enrichment of benzyl alkoxide and the formation of OH* species, thereby improving the overall performance. This work establishes a new paradigm for leveraging local electric field effects in electrocatalyst design, advancing the development of next-generation EHCO systems.