Enhanced photocatalytic behavior of BiVO4 through photoinduced charge transfer to amorphous β-FeOOH nanoparticles

The photocatalytic behavior of the monoclinic BiVO4 coupled with almost-amorphous beta-FeOOH nano particles is reported for the first time. The photoactive properties were examined by means the degradation of the methylene blue dye under UV-vis irradiation conditions. In this regard, the photo degradation kinetic constants were calculated according the Langmuir-Hinshelwood model, where the reaction rate of the pristine BiVO4 was estimated in 7.5 x 10(-5) s(-1). When the akaganeite nanoparticles were added to the system, the photodegradation rate increased to 18.7 x 10(-5) s(-1) for the case of the 1% beta-FeOOH/BiVO4 sample. According to the results, we propose that these enhanced photoactive features can be due to the photogenerated electrons that are effectively transferred from the conduction band of the monoclinic BiVO4 to that of beta-FeOOH causing an efficient spatial separation of the charge carriers. Following the nitroblue tetrazolium (NBT) reaction, a decrease in the concentration of the superoxide ions was observed in the beta-FeOOH/BiVO4 photocatalysts. This phenomenon may be justified because the electrons that have migrated can be trapped in the crystalline defects of the almost-amorphous beta-FeOOH nanoparticles or even recombine with the photogenerated holes in the iron oxyhydroxide. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.