Self-supported Ni/Ni3N1−x heterostructures with abundant nitrogen vacancies as efficient electrocatalysts for ethylene glycol oxidation†

Coupling hydrolysis and electrochemical oxidation is an attractive strategy for polyethylene terephthalate (PET) recycling. The development of a highly efficient and stable electro-catalyst for the ethylene glycol oxidation reaction (EGOR) is crucial in this process. In this work, we reported a self-supported Ni/Ni₃N_1−x heterostructure with abundant nitrogen vacancies as highly efficient electro-catalysts to oxidize ethylene glycol to formate with a high faradaic efficiency (94.5%) and selectivity (88.6%). The combination of advanced spectroscopic techniques and density functional theory calculations reveals that the presence of nitrogen vacancies shifts the Ni d-band center towards the Fermi level, thus enhancing the adsorption of EG and lowering the energy required for state transition in the EGOR. The result of this work can guide the development of highly active EGOR electrocatalysts, promoting the application of recycling waste PET plastics through hydrolysis coupled with electrochemical oxidation processes.