Upcycling Plastic Waste: Ce-Doped Co-Based Metal–Organic Framework Synthesis Using Discarded Polyethylene Terephthalate and Electrooxidation of Polyethylene Terephthalate Hydrolysate Coupled with Hydrogen Production

The electrochemical upcycling of polyethylene terephthalate (PET) into more valuable substances offers a feasible way to address the issue of PET plastic contamination. Herein, we successfully synthesized a Ce-doped Co metal–organic framework (Co-MOF) electrode (CeCo-MOF/NF) and resynthesized CeCo-MOF/NF (R-CeCo-MOF/NF) by employing recycled terephthalic acid derived from waste PET plastics on nickel foam (NF). By utilizing CeCo-MOF/NF as both the cathode and anode, Ce–Co(OH)₂ and Ce–CoOOH were in situ reconstructed as highly effective species for hydrogen evolution reaction and PET hydrolysate oxidation. CeCo-MOF/NF exhibits excellent catalytic performance for hydrogen evolution reaction in alkaline media. Meanwhile, CeCo-MOF/NF achieves a current density of 100 mA cm⁻² at only 1.30 and 1.34 V vs. reversible hydrogen electrode during the ethylene glycol oxidation reaction and PET hydrolysate oxidation, respectively. Furthermore, R-CeCo-MOF/NF demonstrates stable and ideal performance in ethylene glycol oxidation reaction and PET hydrolysate oxidation. This study proposes an energy-efficient and cost-effective electrolysis pathway for developing efficient electrocatalysts to facilitate sustainable plastic recycling and advance the development of a zero-carbon economy.