Integrated High-Entropy Oxy-Carbide for Co-Production of Benzoquinone and Hydrogen at Ampere-Level Current Density

The rational design of high-performance, high-entropy inorganic electrocatalysts is crucial for advancing energy conversion technologies. This work reports an aqueous-emulsion polymerization-induced self-assembly strategy to fabricate spherical mesoporous high-entropy oxy-carbide nanoparticles (HEOCs) anchored on nitrogen-doped mesoporous carbon spheres (NMCSs). The derived (FeCoNiCrMo)(C, O)/NMCS composite demonstrates exceptional electrocatalytic performance. It exhibits a low overpotential of 310 mV and a small Tafel slope of 48.5 mV dec⁻¹ for the oxygen evolution reaction (OER), superior to its quaternary carbide and oxide, and quinary oxide counterparts. Remarkably, it also catalyzes the electrochemical oxidation of phenol (EOP) to the value-added chemical p-benzoquinone with a lower overpotential of 270 mV at 100 mA cm⁻². When replacing the anodic OER with this thermodynamically favorable EOP, the integrated electrolysis system (EOP||HER) achieves simultaneous H₂ production and chemical synthesis, requiring only 1.42 V vs. RHE to deliver a Faraday efficiency of 93.5% for p-benzoquinone. The electrolyzer demonstrates exceptional stability at an industrial-grade current density of 1 A cm⁻² for over 100 h. In situ Raman spectroscopy reveals the reaction pathway and confirms the active-phase evolution. This work provides a strategy for designing multifunctional high-entropy inorganic materials and demonstrates their promising application in energy-saving integrated electrochemical systems for concurrent chemical transformation and energy conversion.