Selective Electrooxidation of Ethylene Glycol to Formate with Green Hydrogen in Co–O–Fe Clusters via Electron Localization-Mediated Dual-Site Synergy

Abstract The electrocatalytic upgrading of waste plastic-derived ethylene glycol to value-added chemicals is a promising route toward a circular carbon economy, yet it remains challenged by the lack of efficient non-noble catalysts with well-defined active sites and well-elucidated synergistic mechanisms. Herein, we report a fundamental study that goes beyond catalyst development to unveil a unique electron-buffering mechanism within Co–O–Fe clusters in CoFe-layered double hydroxide. This effect, coupled with the nanoneedle architecture, enables exceptional ethylene glycol oxidation reaction (EGOR) performance. A current density of 50 mA cm–2 is achieved at 1.52 V vs reversible hydrogen electrode (RHE), and a formate Faradaic efficiency of 92.02% is reached at 1.7 V vs RHE after 6 h of electrolysis. More importantly, through a combination of in situ characterization and theoretical calculations, we decipher the distinct roles of the dual sites: Fe sites act as electron reservoirs, stabilizing low-valence Co, and, synergizing with Jahn–Teller distortion, primarily facilitate dehydrogenation and C–H activation. In turn, the Co sites are identified as the active centers for the directional cleavage of the C–C bond in glycolate/glyoxylate intermediates. Electron transfer through the Co–O–Fe bridge dynamically modulates the energy landscape of intermediates, steering the pathway selectively toward formate. When implemented in a coupled HER∥EGOR electrolyzer, this mechanism enables low-energy hydrogen production (5.97 kWh m–3). Our work provides atomic-level insight into cooperative electrocatalysis, offering a new design paradigm for the green and high-value transformation of carbon-based plastics.