Concurrent Production of Glycolic Acid via Anode Valorization of Plastic Paired with Cathode Upcycling of Biomass Derivative.

Abstract

Electrochemical upcycling of polyethylene-terephthalate-derived (PET-derived) ethylene glycol (EG) into valuable chemicals, such as glycolic acid (GA), provides a sustainable route for reclaiming the carbon resource in plastic wastes. However, valorization of EG to GA is realized solely via anodic oxidation, which is typically accompanied with the generation of low-value hydrogen at cathode. Here, we develop a GA production system that combines anodic and cathodic GA production via oxidation of PET-derived EG paired with reduction of biomass-derived oxalic acid, which is made possible by the discovery of robust PdBi alloy anode and earth-abundant TiO2 cathode. Building on the theoretical understanding and experimental demonstration of anti-CO poisoning on the PdBi anode and temperature-dependent GA electrosynthesis on the TiO2 cathode, our integrated electrochemical system achieves a total Faradaic efficiency of 182% for GA production. This proof-of-concept electrochemical coupling strategy paves a way for high-efficiency utilization of surplus plastic-/biomass-derived feedstocks via renewable-electricity-driven electrocatalysis.