Dual‑Doped Nickel Sulfide for Electro‑Upgrading Polyethylene Terephthalate into Valuable Chemicals and Hydrogen Fuel

Electro-upcycling of plastic waste into value-added chemicals/fuels is an attractive and sustainable way for plastic waste management.Recently,electrocatalytically converting polyethylene terephthalate(PET)into formate and hydrogen has aroused great interest,while developing low-cost catalysts with high efficiency and selectivity for the central ethylene glycol(PET monomer)oxidation reaction(EGOR)remains a challenge.Herein,a high-performance nickel sulfide catalyst for plastic waste electro-upcycling is designed by a cobalt and chloride co-doping strategy.Benefiting from the interconnected ultrathin nanosheet architecture,dual dopants induced upshifting d band centre and facilitated in situ structural reconstruction,the Co and Cl co-doped Ni_(3)S_(2)(Co,Cl-NiS)outperforms the singledoped and undoped analogues for EGOR.The self-evolved sulfide@oxyhydroxide heterostructure catalyzes EG-to-formate conversion with high Faradic efficiency(>92%)and selectivity(>91%)at high current densities(>400 mA cm^(−2)).Besides producing formate,the bifunctional Co,Cl-NiS-assisted PET hydrolysate electrolyzer can achieve a high hydrogen production rate of 50.26 mmol h^(−1)in 2 M KOH,at 1.7 V.This study not only demonstrates a dual-doping strategy to engineer cost-effective bifunctional catalysts for electrochemical conversion processes,but also provides a green and sustainable way for plastic waste upcycling and simultaneous energy-saving hydrogen production.