Durable TiO Heterojunction Composite Membrane Encapsulating N-Doped Graphene Nanosheets for Efficient Electro-Oxidation of GenX and Other PFAS in Fluorochemical Wastewater.

Rational interfacial engineering design of an electrocatalyst, such as a heterojunction structure, can effectively enhance its catalytic activity. This study aims to address a critical challenge associated with the use of carbon material@TiO heterojunction composite electrodes for wastewater treatment─electrode stability over long-term operation. Herein, we report a highly stabilized interfacial engineering strategy, i.e., the use of conductive inorganic CeO as a "cement" to firmly encapsulate N-doped graphene oxide nanosheets (N-GS) on the TiO surface. The defect-rich N-GS encapsulated on the TiO surface significantly enhances interfacial charge transfer. This enhancement results in the N-GS/CeO@TiO heterojunction composite electrode exhibiting excellent efficiency in the electro-oxidation of hexafluoropropylene oxide dimer acid (HFPO-DA or GenX). Furthermore, a flow-through N-GS/CeO@TiO reactive electrochemical membrane system effectively mineralizes other 35 PFASs in a real fluorochemical wastewater sample, achieving a high defluorination rate of 70-90% and exhibiting better performance in PFAS destruction and energy efficiency compared to the UV/KI-SO process. Results of this study enhance our understanding of the electrochemical oxidation of PFAS and offer valuable insight into the design of stabilized TiO heterojunction composites. These findings are instrumental in advancing the development of effective treatments for PFAS-contaminated environments.