光催化剂BiVO_4的制备、表征及其光催化性能的研究

Study on the Preparation,Characterization and Activity Evaluation of BiVO_4 Photocatalyst

采用化学沉淀法制备光催化剂BiVO4,用紫外-可见光谱、X射线衍射对其进行表征。通过光催化还原铬离子和光催化氧化甲基橙的效率来评价该催化剂的活性。实验研究了不同的焙烧温度和不同的焙烧时间对光催化剂BiVO4催化活性的影响。结果表明,制备光催化剂BiVO4的最佳条件是在600度下恒温3h。光催化剂BiVO4在可见光和紫外光的照射下均有较好的光催化还原活性和光催化氧化活性。BiVO4从正方晶相向单斜晶相转化的最佳温度是600°C。焙烧过的BiVO4的紫外-可见吸收光谱较未焙烧的有较大程度的红移,提高了对光的利用率。实验同时还探讨了影响BiVO的光催化活性的机理。

The photocatalyst BiVO4 was prepared by the chemical precipitation method. The photocatalyst was characterized by X - ray powder diffraction （XRD） and UV - Vis diffuse reflectance spectroscopy （ UV - Vis）. The photocatalytic activity of the photocatalyst was evaluated by photocatalytic reduction of Cr2072- and photocatalytic oxidation of Methyl Orange （MO）. The effect of different calcination temperatures and different calcination time on the photocatalytic activity of BiVO4 was investigated, respectively. The results showed that the optimum calcination temperature and the optimum calcination time were 600℃ and 3h, respectively. The photocatalyst BiVO4 has good photocatalytic reduction activity of Cr2O72- and photocatalytic oxidation activity of Methyl Orange （MO） under visible and UV light irradiation. The optimum temperature for the photocatalyst BiVO4 transform from tetragonal phase to monoclinic phase was 600℃. Compared with BiVO4 without heat treatment, the photoabsorption wavelength range of the calcined BiVO4 red shifts and improves the utilization of the total spectrum. The possible mechanisms of influence on the photocatalytic activity of the BiVO4 photocatalyst were also discussed.