Tungsten Oxide

Bismuth tungstate is a new type of photocatalyst which has attracted much attention in recent years. It has not only good catalytic performance, stable photocatalytic activity, but also non-toxic environment. It is becoming a new hot spot in the field of photocatalyst. The liquid phase methods for preparing bismuth tungstate include solvothermal method, precipitation method, microemulsion method, hydrothermal method, etc.. Among the many methods, hydrothermal method has become the most popular method because of its simple operation process, high utilization ratio of raw materials, less energy consumption, and conforms to the policy of energy saving and emission reduction. The working principle of the hydrothermal method is in a closed reaction vessel special (autoclave), using aqueous solution as reaction medium, heating the reaction vessel, creating a high temperature and high pressure reaction environment, the insoluble substances dissolved in normal temperature and ...

Hydrothermal process is carried in a special closed reaction vessel (reactor), the aqueous solution as medium, by heating the reaction vessel to create a high-temperature, high-pressure reaction environment to make the generally insoluble or poorly soluble material to dissolve and recrystallization, and then by filtering, washing, drying and other separation means to get the ultra-fine, high-purity particles. Hydrothermal method for preparing hexagonal tungsten trioxide, its crystalline form is affected by many factors, such as pH value, hydrothermal temperature and additives and others, the following will specifically analyze the impact of various factors. In the hydrothermal environment to prepare tungsten trioxide , the existence of hydrogen ions (H + ) is one of the important factors which affect crystal form of product, especially when the reaction condition is acidic environment. The influence mechanism of pH on tungsten trioxide crystal form is really complex, it is...