Electro-photocatalytic degradation of acid orange II using a novel TiO2/ACF photoanode

Abstract

A novel photoanode was prepared by immobilizing TiO 2 film onto activated carbon fibers (TiO 2 /ACF) using liquid phase deposition (LPD) to study the electro-photocatalytic (EPC) degradation of organic compounds exemplified by an azo-dye, namely, Acid Orange II (AOII).Results demonstrated that by applying a 0.5 V bias (vs. SCE) across the TiO 2 /ACF electrode, the AOII degradation rate was increased significantly compared to that of photocatalytic (PC) oxidation. The application of an electric field promotes the separation of photogenerated electrons and holes as confirmed by electrochemical impedance spectroscopy (EIS) measurements. The structural and surface morphology of the TiO 2 /ACF electrode was characterized by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). SEM images showed that TiO 2 was deposited on almost every carbon fiber with an average thickness of about 200 nm with the inner space between neighboring fibers being maintained unfilled. The morphological features of the photo-anode facilitated the passage of solution as well as UV light through the felt-form electrode and created a threedimensional environment favorable to EPC oxidation. Both the large outer surface area of the 3D electrode and the good organic adsorption capacity of the ACF support promoted high contact efficiency between AOII and TiO 2 surface. Anatase was the major crystalline TiO 2 deposited. UV-vis spectrophotometry, TOC (total organic carbon) analysis, and HPLC technique were used to monitor the concentration change of AOII and intermediates as to gain insight into the EPC degradation of AOII using the TiO 2 /ACF electrode. IntroductionThe degradation of organic pollutants in water by the photocatalytic semiconductor TiO 2 has attracted extensive attention in recent decades. Many researchers have reported that most refractory organic contaminants such as detergents, dyes, pesticides, and herbicides, can be decomposed by TiO 2 under UV-light irradiation. It has been known also that conventional photooxidation has two major disadvantages: difficulty in solid-liquid separation and low photo-efficiency. For use in TiO 2 suspension, extra effort is needed to separate the photocatalytic TiO 2 particles from water. To deal with the 0 7 ( 2 0 0 9 ) 2 4 3 1 -2 4 3

Liquid phase deposition of hemoglobin/SDS/TiO2 hybrid film preserving photoelectrochemical activity

“…The as-prepared LPD TiO 2 films exhibit high photoelectrochemical activity and can be applied to the degradation of organic pollutants [29,30]. Meanwhile, LPD technique also provides a ready process for forming TiO 2 -based hybrid thin films by simply doping organic or biological materials into the deposition solution [31][32][33][34][35].…”

Photoelectrochemical activity of liquid phase deposited TiO2 film for degradation of benzotriazole

“…Using the LPD process, TiO 2 films have been prepared and applied to photocatalysis [26,27] and electrocatalysis [28]. The photoelectrocatalytic (PEC) degradation of acid orange II using the LPD TiO 2 film-coated activated carbon fiber has been reported [29]. However, the PEC degradation of emerging contaminants over LPD TiO 2 films has not been explored.…”

TIO2-MODIFIED ZEOLITE-CARBON NANOTUBES COMPOSITE ELECTRODE FOR PHOTOELECTRODEGRADATION OF PENTACHLOROPHENOL FROM WATER UNDER UV IRRADIATION

“…Thus, for the degradation of pollutants from water, the combination of electrochemical and photocatalysis processes, such as photoelectrocatalysis [14] and electrochemically-assisted photocatalysis [15] processes, have been reported. The main difference between these variants is denoted by which of these represents the core process.…”