Effects of pH on Hydrothermal Synthesised Bismuth Vanadate Photocatalysts and Its Properties

Bismuth vanadate(BiVO4) powders were synthesized using the hydrothermal strategy with bismuth nitrate and ammonium metavanadate as inorganic sources,NaOH for pH adjustment.The materials were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and UV-vis diffuse reflectance spectra techniques(UV-vis DRS).It revealed that the pH values of the precursors can influence significantly on the particle structures and morphologies of the BiVO4 products.The decomposition of rhodamine B(RhB) in aqueous solution under visible light(λ 420 nm)irradiation and variation of TOC concentration were evaluated.The results showed that photocatalytic activities of BiVO4 samples prepared at different pHs varies greatly,and the optimum pH value is about 6.7,which photodegradation rate could be up to 95.3% in 4 h,the reduction of TOC concentration in the degradation of RhB indicated that the mineralization of RhB occurred.Additionally,the relationship between the phase,morphology of photocatalysts and their photocatalytic activities are also discussed.