Photoelectrocatalytic removal of dye and Cr(VI) pollutants with Ag2S and Bi2S3 co-sensitized TiO2 nanotube arrays under solar irradiation

摘要

Ag2S and Bi2S3 nanoparticles co-decorated TiO2 nanotube arrays (TiO2 NTs/Ag2S-Bi2S3) with high visible light activities were successfully prepared by using two-step processes of an electrochemical anodization followed by a successive ionic layer adsorption and reaction (SILAR) method. The phase composition, morphology and microstructure were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM) and UV vis diffusion reflection spectroscopy (DRS), and Ag2S and Bi2S3 nanoparticles were uniformly dispersed on the surface of TiO2 NTs. The as-prepared TiO2 NTs/Ag2S-Bi2S3 photoelectrodes significantly improved the visible light photocurrent response due to the acceleration of charge transferring on the formed heterojunction surface and the suppression of electron/hole pairs from the recombination. The results indicated that the co-sensitization largely enhanced the photoelectrocatalytic (PEC) removal efficiencies of methylene orange (MO), rhodamine B (RhB) dyes and Cr(VI) ions. The heterogeneous TiO2 NTs/Ag2S-Bi2S3 photocatalysts show a promising significance in the PEC removal of organic and heavy metal ion pollutants, which provides a typical model for TiO2 NT films used as energy and environmental materials. (C) 2016 Elsevier B.V. All rights reserved.