Hybrid Oxidization of Ethylene Glycol on Defective Ag-PtPd Electrocatalyst Beyond 3000 h Stability at an Industrial-Scale Current Density

Abstract

Electrochemical oxidization of crude ethylene glycol (EG) to fine chemicals driven by sustainable energy is an eco-friendly solution to the upcycling of end-of-life polyethylene terephthalate (PET) wastes. Here, pseudo Ag_x-Pt_yPd_z core–shell electrocatalyst capable of hybrid oxidation of EG to formate (FA) is designed and synthesized. The trimetallic system consists of Ag nanowire and ultrathin PtPd alloy skin with defects, such as holes and grooves. The defects expose the Ag core to the surroundings and convert Ag⁰ to Ag²⁺ active species at appropriate potential (> 1.2 V vs RHE). Thus, hybrid EG oxidization reaction is realized on the Ag_x-Pt_yPd_z electrocatalyst, where PtPd skin catalyzes EG oxidization through conventional Faradaic electrode process owing to inherent activities of Pt and Pd, while Ag²⁺ serves as auxiliar oxidant to oxidize EG/intermediates (non-Faradaic reaction). Such a hybrid oxidization strategy reinforces the removal of adsorbates on Ag_x-Pt_yPd_z electrocatalyst and refresh the active sites timely. Eventually, ultrahigh specific activity (24.45 A mg⁻¹_PtPd) and long-term stability (> 3000 h at current density ≥ 400 mA cm⁻²) are delivered by the system. The finding of Ag²⁺-enhanced alcohol oxidization reactions introduces a new paradigm for designing high-performance electrocatalysts for energy and environmental applications.