Highly active cobalt oxide-palladium nanohybrid catalyst enables selective electrocatalytic synthesis of glycolic acid

Abstract

Glycolic acid is a unique value-added chemical, while its large-scale production is limited by harsh synthesis conditions and poor selectivity. Herein, we have ingeniously constructed a highly active cobalt oxide-supported palladium electrocatalyst on nickel foam (Pd-Co3O4/NF) for ethylene glycol oxidation to glycolic acid with a high Faradaic efficiency (93.1 %) at ultra-low potential (0.9 V vs. RHE). In situ Fourier transform infrared spectroscopy revealed the pathway of ethylene glycol oxidation reaction (EGOR). The theoretical results reveal that Co3O4/NF can effectively promote the formation of *OH and weaken the adsorption of toxic *CO intermediates on Pd-Co3O4/NF. And the downshifted d-band center of Pd-Co3O4/NF is inducive to facilitate the desorption of GA from the Pd surface, prevents the excessive oxidation thus improving the selectivity. Moreover, Pd-Co3O4/NF exhibits considerable anode current density with respect to electro-reforming polyethylene terephthalate (PET)-derived EG oxidation, accompanied by the generation of green hydrogen at the cathode. This work puts forward an innovative approach for catalyst construction toward EGOR and highlights the strategy of electro-upcycling of PET.