BiPO_4-BiVO_4复合光催化剂的制备及其光催化性能

采用水热法制备了BiPO_4-BiVO_4复合光催化剂,运用XRD,SEM,UV-Vis DRS技术对其进行了表征,并以亚甲基蓝为目标降解物考察了复合光催化剂在模拟太阳光下的光催化性能。实验结果表明:当BiPO_4与BiVO_4的摩尔比(磷钒比)为2∶8时BiPO_4-BiVO_4的光催化性能最优,光照180 min时对亚甲基蓝(初始质量浓度5mg/L)的降解率达96.20%,反应速率常数为0.018 1 min-1,明显优于单纯BiPO_4和BiVO_4。表征结果显示:单斜相的BiPO_4与BiVO_4晶粒实现了复合生长,BiPO_4-BiVO_4(磷钒比2∶8)的晶粒粒径比单纯BiPO_4和BiVO_4小;复合光催化剂在紫外光和可见光区均具有较好的光响应,且其禁带宽度较BiPO_4明显减小。

Preparation of BiPO4-BiVO4 composites photocatalyst and its photocatalytic capability

BiPO₄-BiVO₄ composite photocatalyst was prepared by hydrothermal method and characterized by XRD,SEM,UV-Vis DRS. Using methylene blue（MB）as the degradation object,the photocatalytic capability of the composite photocatalyst was investigated under simulative sunlight irradiation. The experimental results show that the BiPO₄-BiVO₄ with 2∶8 of molar ratio of BiPO₄ to BiVO₄ shows the best photocatalytic capability,the degradation rate of MB（initial mass concentration 5 mg/L）is 96.20% after 180 min irradiation and the reaction velocity constant is 0.018 1 min^-1,which are much higher than those on mere BiPO₄ and BiVO₄. The characterized results indicate that：The growth of monoclinic BiPO₄ combined with BiVO₄ crystalline is successfully achieved,and the grain size of BiPO₄-BiVO₄（the molar ratio of BiPO₄ to BiVO₄ is 2∶8）is smaller than pure BiPO₄ and BiVO₄;The composite photocatalyst has good light response under ultraviolet light and visible light,and its band-gap is much narrower than that of pure BiPO₄.