Oxygen vacancy assisted Ru–Ni(OH)2 for efficient ethylene glycol electrooxidation reaction

Abstract

Ethylene glycol oxidation (EGOR) is an important step in polyethylene terephthalate (PET) recycling, and it is a thermodynamically more favorable anode reaction in comparison with the oxygen evolution reaction (OER). A cross-network framework of Ru and S-doped nickel hydroxide with abundant oxygen vacancies (Ru,S–Ni(OH)₂–O_V) on nickel foam (NF) is synthesized by a corrosion method, which is used to produce formate by electrocatalysis of ethylene glycol. Benefiting from the introduction of the S element promoting the formation of oxygen vacancies, Ru,S–Ni(OH)₂–O_V has a strong OH* adsorption capacity when the EGOR occurs, which is demonstrated by the Bode phase diagram and hydroxyl adsorption capacitance (C_φ). With an operating potential of only 1.42 V, the electrode can drive a high current density of 500 mA cm⁻². Ru,S–Ni(OH)₂–O_V also shows excellent selectivity for formate over a wide potential window. The assembled two electrodes for an anion exchange membrane electrolytic cell (AEMWE) can achieve a current density of 500 mA cm⁻² at a voltage of only 1.74 V. This work provides new insights into the development of efficient EGOR electrocatalysts.