Hierarchical P-Decorated Co Nanosheets for Ampere-Grade PET-Derived Ethylene Glycol Valorization Coupled Hydrogen Generation

Abstract Advancing sustainable hydrogen production is pivotal to achieving global carbon neutrality, and thermodynamically favorable ethylene glycol oxidation (EGOR)-assisted water electrolysis provides an energy-saving pathway. Herein, we develop a hierarchical phosphorus-modified Co nanosheet array supported on electrochemically reduced Cu nanowire foam (P-Co@Cu/CF) for ampere-grade paired electrolysis. The three-dimensional Cu scaffold affords a porous and conductive framework that maximizes active-site exposure and accelerates mass/electron transport, while P incorporation tailors the electronic structure of Co, optimizing intermediate adsorption and promoting rapid catalytic kinetics. Benefiting from these synergistic effects, the catalyst demonstrates outstanding performance at ampere-grade current densities for both the EGOR and HER. In a two-electrode HER∥EGOR system, current densities of 1 A cm−2 are delivered at cell voltages of 1.68 V, while maintaining > 90% Faradaic efficiency for H2 and an impressive formate yield rate of 9.81 mmol h−1 cm−2 at 1 A cm−2, with sustaining continuous stable electrolysis for over 100 h at 800 mA cm−2. Operando spectroscopy results and electrochemical analyses reveal that surface-reconstructed active species drive EG oxidation via a coupled electrochemical–chemical pathway involving glyoxal intermediates.