Enhanced Visible-Light Photoelectrocatalytic Degradation of Organic Contaminants at Iodine-Doped Titanium Dioxide Film Electrode

For the sake of effectively utilizing visible light of the solar spectrum in photoelectrocatalytic (PEC) degradation of organic contaminants, iodine-doped TiO 2 nanocrystallites (I-TNCs) film electrodes with extended response to visible light and mesoporous nanocrystalline framework were fabricated and subsequently characterized by scanning electronic microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and diffuse reflectance spectrum (DRS). The PEC activity of the film electrodes was evaluated by the degradation of rhodamine B (RhB) and 1-naphthol (1-NP) in aqueous solution at ambient conditions under visible irradiation. Under an optimized I/Ti doping ratio of 2.5 mol %, the PEC performance of the film electrode based on I-TNCs is significantly better, with the RhB degradation efficiency of 92%, which was nearly 2-fold faster than that of the film electrode based on undoped TNCs. In comparison with photocatalytic (PC) process and electrochemical (EC) process, a significant synergetic effect was observed in the PEC degradation of organic contaminants. The main degraded products of 1-NP were further analyzed by GC-MS and ca. 70% of TOC removal was obtained.