Engineering High-Spin Ruthenium Centers via Gradient Orbital Coupling for Electrocatalytic PET Upcycling

Tailoring the d-orbital spin state is a powerful strategy to accelerate the sluggish ethylene glycol oxidation reaction (EGOR) in polyethylene terephthalate (PET) upcycling. Herein, we engineered a Y 2 Ru 2 O 7 /CeO 2 (YRO/CeO 2 ) heterojunction featuring an interfacial Ce(4f)−O(2p)−Ru(4d) gradient orbital coupling. This structural modulation steers Ru active sites from an inert low-spin to a highly active high-spin configuration. By optimizing intermediate orbital overlap, this transition significantly lowers the computed energy barrier for the rate-determining C−C cleavage. Consequently, the catalyst delivers 100 mA cm −2 at merely 1.41 V vs RHE. Integrated into a membrane electrode assembly, it operates robustly for over 400 h, yielding a 13.22% energy saving over conventional water splitting. Using authentic PET hydrolysate, our system coproduces high-purity terephthalic acid, potassium diformate, and green hydrogen, validating interface-driven spin engineering as a highly efficient plastic valorization paradigm.