水热法制备BiVO_4及其光催化性能研究

采用水热反应法并改变反应条件制备不同形貌和晶体结构的BiVO4可见光催化剂,并探讨不同形貌BiVO4的形成机制及其光催化活性的影响因素。借助X-射线衍射（XRD）、扫描电子显微镜（SEM）及固体紫外-可见漫反射光谱（DRS）对产品进行表征,并在可见光（λ〉420 nm）照射下考察其降解亚甲基蓝（MB）的光催化性能。结果表明,高温更有利于单斜型钒酸铋的生成,反应初始pH值对钒酸铋的形貌影响较大。反应过程中,前驱液中的颗粒通过溶解再结晶、定向聚集自组装、熟化过程最终形成不同形貌的钒酸铋颗粒。钒酸铋的光催化降解速率主要受其晶粒粒径和晶体微观应变的影响,晶粒粒径越大,微观应变越小,结晶度越好,降解速率越高。

Hydrothermal synthesis and photocatalytic performance of BiVO_4

Visible-light photocatalyst BiVO4with different structure and morphologies were synthesized by hydrothermal synthesis method,with reaction conditions changed. The formation mechanism and influence factor of photocatalytic performance of different morphologies of BiVO4was discussed. The properties of products were characterized by XRD,SEM,and UV-Vis. The photocatalytic performance of BiVO4was measured by the photodegradation of methylene blue（ MB） under visible-light irradiation（ λ 420 nm）. The results showed that monoclinic BiVO4was obtained more easily with high reaction temperature,and the morphology were influenced by the initial pH of reaction precursor solution. In the process of reaction, BiVO4with different morphologies were formed by particles in precursor liquid which experienced dissolve the recrystallization,oriented aggregation and ripen. And the crystallite size and strain have a big effect on the photocatalytic activity of BiVO4,the bigger crystallite size and the less strain value,the higher crystallinity,the higher photocatalytic activity.