Electronic Modulation of Iron-Modified Nickel Diselenide for Practical Electrochemical Upcycling of PET-Derived Ethylene Glycol into Formate

Abstract The continuous accumulation of global polyethylene terephthalate (PET) plastic waste has triggered a severe environmental crisis. As a sustainable solution, the electrocatalytic ethylene glycol oxidation reaction (EGOR) converts the alkaline hydrolysis product of PET into high-value chemicals while enabling simultaneous cathodic hydrogen evolution, thus offering a promising route for PET waste upcycling. Herein, a series of Fe-modified NiSe2 electrocatalysts are fabricated via a facile one-step hydrothermal method. The optimized electrode based on 5%Fe presence exhibits outstanding EGOR activity in model EG electrolyte, achieving a remarkable current density up to 147 mA cm−2 at an external potential of 1.6 V vs RHE and retaining 88.4% formate Faradaic efficiency over 12 h chronoamperometry. Density functional theory calculations verify that Fe introduction modulates electronic structure of the parent nickel diselenide, accelerates interfacial charge transfer, and reduces the energy barrier for critical C–C bond cleavage to boost reaction kinetics. More importantly, electrolysis tests using real alkaline PET hydrolysate confirm its practical feasibility. The hydrolysate derived from 1.5 g PET enables an EGOR current density of 128.6 mA cm−2 at 1.6 V vs RHE, presenting a Faradaic efficiency of 87.3% toward formate. This work provides an effective route to design low-cost non-noble electrocatalysts toward practical PET waste electrochemical valorization.