Anodic electrophoretic deposition of Bi2WO6 thin film: high photocatalytic activity for degradation of a binary mixture

Abstract

It is known that many thin films are able to remove pollutants. In the present work, anodic electrophoretic deposition, a low cost, one-step and flexible approach was successfully employed to prepare Bi2WO6 thin films. The film was fabricated from stable suspensions consisted of acetone and Bi2WO6 flower like nanostructures without any dispersant. The deposition was achieved on the anode at applied voltages in the range of 30–70 V using a total solid loading of 0.05-0.20 g L−1 under ambient condition. The kinetics and mechanism of electrophoretic deposition of Bi2WO6 films were studied in details. As-prepared thin films were characterized by scanning electron microscope, energy dispersive X-ray spectroscopy, atomic force microscope, X-ray diffraction, and Raman analysis. Moreover, the photocatalytic activity of thin films was evaluated through degradation of single and binary mixture of 4-cholorophenol and 4-nitrophenol as a pollutant model under natural sunlight and Xe lamp irradiation. A photocatalytic set up with fixed rotating speed was designed for degradation process. The photocatalytic activity was found to be dependent on the substrate and the film thickness. For this purpose, the effect of the film thickness was investigated on the efficiency of photocatalytic degradation in a binary mixture of pollutants. The optimum degradation was achieved by film with thickness of 627 nm.