Monoclinic mesoporous BiVO4: Synthesis and visible-light-driven photocatalytic property

In this paper, we report the synthesis of monoclinic scheelite mesoporous bismuth vanadate by an impregnated-template method. Bismuth nitrate pentahydrate and ammonia metavanadate were respectively used as bismuth and vanadium precursors, and mesoporous SiO2 aerogel was used as a hard template. Monoclinic-phase mesoporous BiVO4 was obtained by heat treatment of the precursor/template, followed by NaOH solution etching to remove SiO2 template. The resultant BiVO4 samples were characterized by X-ray diffraction, N2 adsorption and desorption, UV–vis diffuse reflectance spectra, UV–vis spectroscopy, Raman spectroscopy, and transmission electron microscopy. The results indicate that typical BiVO4 sample has pure monoclinic-phase mesoporous structure and possesses a specific surface area of 20.9 m2 g−1 with a pore size of 18.2 nm. The band gap of such mesoporous BiVO4 was estimated to be 2.05 eV, making them excellent photocatalytic activities under visible light. The photocatalytic efficiency of the monoclinic mesoporous BiVO4 for the degradation of Rhodamine B under the visible light illumination (λ > 400 nm) in 120 min reaches 99%, Besides, the mesoporous BiVO4 photocatalyst still showed high stability: 97% for Rhodamine B degradation after four recycles.