Hydrogen-Bonding Network Modulation via Polydopamine Enabling Efficient Ethylene Glycol Electrooxidation

Electrooxidation reaction of ethylene glycol (EG) offers an efficient route for producing value-added chemicals (glycolic acid (GA)) and facilitates coupled hydrogen (H2) production. However, its practical performance is often hindered by sluggish reaction kinetics and catalyst deactivation, both of which are strongly influenced by interfacial microenvironments. Here, we report an interfacial engineering strategy that employs polydopamine (PDA) to modulate the hydrogen-bonding network at the Au catalyst-electrolyte interface, which mitigates the oxidative deactivation of Au, achieving a 1.78-fold enhancement for electrooxidation of EG-to-GA compared with the pure Au catalyst (0.41 vs 0.23 mmol cm–2 h–1 at 1.5 V vs RHE). Mechanistic studies reveal that Au sites generate reactive OH* species to drive EG oxidation, and the PDA layer enriches EG near active sites. Moreover, PDA can regulate the interfacial hydrogen-bonding network, that is, generating strong hydrogen bonding with EG disrupts the tetrahedral water network, generating a more open and dynamic hydration environment that facilitates EG adsorption and activation. When integrated into a flow-cell electrolyzer, Au/PDA catalyst delivers efficient coproduction of glycolic acid (3.0 mmol h–1) and hydrogen (8.1 mmol h–1) with high selectivity under a 0.8 V operating voltage. This work elucidates a molecular-level mechanism for hydrogen-bond-mediated interfacial regulation and establishes a general design principle for enhancing alcohol electrooxidation through adaptive hydrogen-bonding engineering.