Advanced electrocatalytic reforming of PET-derived ethylene glycol via electric field-driven d-band center modulation

The electrochemical upcycling of polyethylene terephthalate (PET) into high-value products, alongside hydrogen production under ambient conditions, represents a promising approach to sustainable waste management. However, the mechanism underlying efficient PET-derived ethylene glycol oxidation reactions (EGOR), driven by the enhanced adsorption of key intermediates, remains unclear. In this work, built-in electric fields (BIEF) are deliberately engineered within the heterojunction Ni(OH)₂-Ni₃S₂/NF catalyst, effectively elevating the d-band center and thereby enhancing the adsorption of ethylene glycol and hydroxyl (*OH) species. This modification significantly accelerates reaction kinetics compared to Ni₃S₂/NF. Remarkably, the Ni(OH)₂-Ni₃S₂/NF catalyst achieves an industrial current density of 616.0 mA cm^-2 at 1.50 V vs. RHE, exhibiting a Faradaic efficiency (FE) of 89% for formate (FA) at 1.45 V vs. RHE. In situ electrochemical infrared absorption spectroscopy (IRAS) and theoretical calculations reveal that FA is primarily generated through C–C bond cleavage in glycolic acid. This study also elucidates the critical relationship between BIEF and d-band center, offering a viable strategy to enhance intermediate adsorption during the EGOR process.