Photochemical Anti-Fouling Approach for Electrochemical Pollutant Degradation on Facet-Tailored TiO2 Single Crystals.

Abstract

Electrochemical degradation of refractory pollutants at low bias before oxygen evolution exhibits high current efficiency and low energy consumption, but its severe electrode fouling largely limits practical applications. In this work, a new antifouling strategy was developed and validated for electrochemical pollutant degradation by photochemical oxidation on facet-tailored {001}-exposed TiO2 single crystals. Electrode fouling from anodic polymers at a low bias was greatly relieved by the free ·OH-mediated photocatalysis under UV irradiation, thus efficient and stable degradation of bisphenol A, a typical environmental endocrine disrupter, and treatment of landfill leachate were accomplished without remarkable oxygen evolution in synergistic photoassisted electrochemical system. Electrochemical and spectroscopic measurements indicated a clean electrode surface during cyclic pollutant degradation. Such a photochemical antifouling strategy for low-bias anodic pollutants degradation was mainly attributed to the improved electric conductivity and excellent electrochemical and photochemical activities of tailored TiO2 anodic material, whose unique properties originated from the favorable surface atomic and electronic structures of high-energy {001} polar facet and single-crystalline structure. Our work opens up a brand new approach to develop catalytic systems for efficient degradation of refractory contaminants in water and wastewater.