Industrial-grade electrocatalytic valorization of waste plastics via reconstructed Ni ²⁺ -CoOOH nanosheet arrays

Electrocatalytic upcycling of polyethylene terephthalate (PET) waste plastics into value-added chemicals offers a promising strategy to address environmental pollution. However, the development of efficient electrocatalysts capable of operating under industrial-level current densities remains a significant challenge. In this study, we report an electrochemical reconstruction strategy to fabricate Ni²⁺-doped CoOOH nanosheet arrays directly on nickel foam (NF), enabling highly efficient conversion of PET-derived ethylene glycol (EG) into formate at high current densities. Systematic investigations, including <i>in situ</i> spectroscopic analysis, reveal that Ni²⁺ doping not only enhances the adsorption of EG molecules on the catalyst surface but also accelerates the formation of reactive *OH intermediates, thereby improving the reaction kinetics of C–C bond cleavage, ultimately promoting efficient formate production. Specifically, the optimized Ni²⁺-CoOOH₃/NF catalyst achieves an industrial-level current density of 500 mA·cm^-² at an ultralow potential of 1.38 V vs. RHE, with a Faradaic efficiency exceeding 90% across a broad current density range of 100–500 mA·cm⁻². Furthermore, in a practical two-electrode electrolyzer, the Ni²⁺-CoOOH₃/NF delivers a high formate yield of 7.10 mmol·h⁻¹·cm⁻² at 900 mA·cm⁻², along with excellent long-term operational stability.