Design of a Novel Cu2O/TiO2/Carbon Aerogel Electrode and Its Efficient Electrosorption-Assisted Visible Light Photocatalytic Degradation of 2,4,6-Trichlorophenol

Cu2O/TiO2 heterojunction photocatalyst is built on carbon aerogel (CA) substrate with good adsorption properties by sol impregnation and seed mediated synthesis approach. The Cu2O/TiO2/CA electrode has excellent electrosorptive and high efficient photocatalytic properties. Its morphology and surface chemical composition are characterized with SEM, TEM, X-ray diffraction (XRD) and Raman spectra. The UV-vis diffuse reflectance spectra show that the optical absorption edge for Cu2O/TiO2/CA appears at 636 nm. Under visible-light (lambda > 420 nm) irradiation, the photocurrent density increment on Cu2O/TiO2/CA is 60 times of that on Cu2O/TiO2/FTO. The electrochemical characteristic is investigated with electrochemical impedance spectrum (EIS). The Cu2O/TiO2/CA electrode is further applied in the electrosorptive photodegradation of the 2,4,6-trichlorophenol (2,4,6-TCP) wastewater. The result shows that the removal ratio of 2,4,6-TCP in 5.5 h on Cu2O/TiO2/CA is 96.3% and the TOC removal is 91.3%. The intermediates generated in the degradation process are analyzed by GC-MS and HPLC. The possible mechanism of visible light photocatalytic degradation of 2,4,6-TCP on Cu2O/TiO2/CA is also studied.