Preparation of Tungsten Trioxide by Hydrothermal Solvothermal Method

Hydrothermal method refers to a sealed pressure vessel with water as a solvent, the tungsten trioxide powder dissolved and recrystallized material preparation method.

Compared with other powder preparation methods, the tungsten trioxide powder prepared by the hydrothermal method has the characteristics of complete grain growth, small grain size and even distribution. The tungsten trioxide particles obtained by the hydrothermal method are agglomerated lightly, and the suitable stoichiometry and crystal form are easily obtained. The solvothermal method is developed on the basis of hydrothermal method. It refers to a synthesis method in which the original mixture is reacted in a closed system such as an autoclave with an organic or nonaqueous solvent as a solvent at a certain temperature and under autogenous pressure of the solution. It differs from the hydrothermal reaction in that the solvent used is organic rather than water.

Hydrothermal solvothermal method is a common method for the growth of tungsten trioxide crystals. This method, also known as high-pressure solution method, is a process in which a high-pressure environment is generated by heating in a closed container under conditions of high temperature and high pressure to dissolve and recrystallize substances that are insoluble or poorly soluble at normal temperature and pressure. Due to the high temperature and pressure environment, tungsten oxide properties will change. Which will produce different products at room temperature and pressure. Compared with the sintering process, the method has a lower synthesis temperature.

Thus making tungsten oxide crystals produce fewer defects during growth. Compared with the normal pressure heating method, the higher synthesis pressure makes the crystal of tungsten oxide have higher crystallinity in the growth process. At the same time hydrothermal / solvent heat process, its strong convection will make mass transfer more uniform and fast. At the same time, due to the small reaction temperature gradient, tungsten oxide crystals grow with higher growth rate and uniformity. Therefore, the hydrothermal / solvothermal method of tungsten trioxide, tungsten oxide photocatalyst will have better performance.

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