Soft Chemical Preparation Of BiVO₄Nano Particles And Characterization Of The Catalytic Properties Under Visible Light

This paper was committed to study the soft-chemical preparation of monoclinic BiVO4nano-particles and the photocatalytic properties. The main contents were concluded as follows:1. BiVO4nano-powders have been synthesized by a typical hydrothermal method without HNO3.The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis absorption spectroscopy. The photocatalytic activity was estimated by the degradation of RhB under visible light irradiation. The results show that both reaction temperature and pH affect the synthesis process significantly. When the reaction time was set as36h, Bi4V2O11appeared as impurity below160℃. While the temperature was increased to160℃, pure BiVO4can be prepared in alkaline and acidic condition,respectively. In this study, the sample prepared at160℃under pH9has the highest photocatalytic activity.2. BiVO4nano-powders have been synthesized by an alcohothermal method with ethylene glycol. The photocatalytic activity was estimated by the degradation of RhB under visible light irradiation. The results show that HNO3will lead to an accumulation of the precursor. During the early stage, it can promote the crystallization, but when it turns into the later stage, HNO3will lead to a particle agglomeration. In this study, the sample prepared at100℃without HNO3shows out the highest photocatalytic activity.3. BiVO4nano-powders have been synthesized by a sol-gel method. The results show that response parameters such as dispersant composition, calcining time, calcining temperature, pH and different surfactant all affect the sol-gel process. In aqueous system, the sample prepared under pH7and calcined at500℃has the highest activity. When it goes to alcohol system, the sample prepared with PEG and calcined at500℃shows out the highest activity.