Electrochemical upcycling of PET to value-added chemicals via amorphous–crystalline interface engineering

Abstract

Electrochemical upcycling of polyethylene terephthalate (PET) via oxidation of ethylene glycol (EG), a key depolymerization product, provides a sustainable route to convert plastic waste into value-added chemicals using renewable electricity. However, limited surface wettability and suboptimal intermediate adsorption hinder catalytic activity and selectivity. Herein, we report a hierarchical NiCu layered double hydroxide NiCu–LDH/NiCo₂O₄ heterostructure on nickel foam, featuring well-defined amorphous-crystalline interfaces for efficient EG oxidation. The amorphous NiCu–LDH component improves surface wettability and electrolyte penetration, while the crystalline NiCo₂O₄ scaffold provides high electrical conductivity and mechanical robustness. Notably, strong interfacial electronic coupling optimizes the adsorption of EG and OH* intermediates, thereby accelerating reaction kinetics. The improvements in surface wettability, together with interfacial electronic interactions, collectively enhance catalytic performance. The catalyst delivers high current densities of 100 and 500 mA cm⁻² at 1.353 and 1.470 V versus RHE, achieves ∼90% faradaic efficiency for formate across 1.30–1.70 V, and shows negligible current decay over 120 h. The estimated economic benefit of practical PET upcycling is $205.33 per ton. These results highlight that combining enhanced wettability with interfacial electronic modulation provides an effective strategy for sustainable plastic waste valorization.