Strongly Coupled Ru–Co3O4 Heterointerfaces Accelerate Ethylene Glycol Electroreforming for Efficient Paired Hydrogen/Formate Electrosynthesis

Abstract Engineering strongly coupled metal–oxide interfaces is an effective strategy for regulating the electronic structure and catalytic kinetics of electrocatalysts. Herein, we report a Ru–modified Co3O4 nanosheet array grown on nickel foam (Ru@Co3O4/NF), in which the strongly coupled Ru–O–Co interface and synergistic dual-active-site effect induce significant charge redistribution and optimized adsorption behavior toward key intermediates. Benefiting from these advantages, the Ru@Co3O4/NF catalyst delivers the highest formate Faradaic efficiency (FE) of 96.97% with a formate production rate of 129.6 mg h−1 cm−2 at 1.8 V for the ethylene glycol oxidation reaction (EGOR), together with a low hydrogen evolution reaction (HER) overpotential of 128 mV at 1000 mA cm−2. Operando spectroscopic analysis combined with theoretical calculations demonstrates that the strongly coupled Ru–Co3O4 interface effectively modulates the electronic structure and accelerates the formation and conversion kinetics of key intermediates during both HER and EGOR, thereby enabling enhanced catalytic performance. Notably, the Ru@Co3O4/NF-based paired electrolyzer simultaneously achieves high FEs for both formate and H2 production, together with superior long-term operational stability over 120 h, highlighting its great potential for sustainable hydrogen production and value-added alcohol electroreforming.