Electro-upgrading of polyethylene terephthalate (PET) alkaline hydrolysate provides an energy-saving strategy towards green hydrogen and value-added anodic products, but their selectivity and stability under industrial-scale current densities (>200 mA cm-2) remain challenging. Herein, hierarchical Co-CeF3@Ni3N sheet-on-sheet nanostructures supported on nickel foam (Co-CeF3@Ni3N/NF) were fabricated for PET hydrolysate electro-upgrading coupled with H2 generation. The hierarchical nanostructures can enlarge accessible active area, while the introduction of Co species can modulate electronic configuration, which can reduce active species formation potential and optimize the adsorption behaviors of key reactants and reactive intermediates. Therefore, Co-CeF3@Ni3N/NF exhibits industrial-scale response current densities (80 to 380 mA cm-2) at applied potential around 1.32-1.44 V vs. RHE, as well as high stability (over 60 h) and high faradaic efficiencies (FEs >97%) in ethylene glycol oxidation reaction (EGOR), which is superior than most of the high-end electrocatalysts. In situ characterizations and electrochemical measurements indicate the key active species and crucial intermediates in EGOR, proposing a reaction pathway towards high selectivity of formate. Moreover, continuous flow cell with Co-CeF3@Ni3N/NF as bifunctional electrode for electro-upgrading PET hydrolysate delivers high activity (over 300 mA cm-2 at 1.72 V), long-term stability (144 h) and high FEs (>95%). This study develops a bifunctional electrocatalyst for EGOR and HER, while elucidating the active species, key intermediates, and possible reaction pathway for close-loop electro-upgrading of PET waste.
