A Molten Salt-Like Strategy for the Synthesis of Hierarchical NiCoMn-LDH Electrocatalysts for Electrocatalytic Upcycling of Polyethylene Terephthalate Waste

Abstract The electrochemical upcycling of polyethylene terephthalate (PET) waste into value-added chemicals is widely recognized as a sustainable strategy for mitigating plastic pollution and valorizing carbon resources. However, developing nonprecious electrocatalysts with high selectivity, and stability at industrial current densities remains a major challenge. Herein, we report the synthesis of a trimetallic NiCoMn-layered double hydroxide (NiCoMn-LDH) catalyst using a molten salt-like strategy. This method avoids the use of any external solvent or additive, instead harnessing the crystal water inherent in metal salts to create a homogeneous reaction environment, thereby eliminating liquid waste and conserving water resources. The NiCoMn-LDH catalyst exhibits exceptional performance toward the ethylene glycol oxidation reaction (EGOR), delivering a current density of 300 mA cm–2 at 1.32 V vs RHE, along with a Faradaic efficiency of 88% and a formate selectivity of 97.8%. Upon integrated into a solid polymer electrolyte with a geometric area of 100 cm2, the catalyst maintains stable operation for over 100 h at 300 mA cm–2 with minimal voltage degradation (∼1.427 V). Notably, when ethylene glycol derived from real PET waste is utilized, the system retains a formate Faradaic efficiency of 92.4%, thereby demonstrating its practical viability for plastic upcycling. In this work, an eco-friendly synthesis route and a high-performance nonprecious catalyst system for electrochemical waste valorization are presented, offering a promising pathway toward a sustainable plastic refinery.