The ammonium ion in urea stabilizes the skeleton of tungsten trioxide. If the removal of ammonium trioxide in the framework of ammonium ions, will lead to the collapse of the framework of tungsten trioxide. This shows that the monovalent cation in urea plays an important role in stabilizing the structure of tungsten trioxide. Since urea hydrolyzes under hydrothermal conditions, ammonium and bicarbonate ions are released and the pH of the reaction system is slowly adjusted.

When different ions are present in the solution, they will have different effects on the activity of the tungsten oxide photocatalyst. The reason for the influence is similar to the dye sensitization process of tungsten oxide photocatalyst, and the activity of the tungsten oxide photocatalyst is changed by changing the surface structure of the tungsten oxide photocatalyst.

Tungsten tailings are the solid wastes produced after the classification of tungsten ore. At present the comprehensive utilization mainly includes the recovery of useful metals and non-metallic ores, but the amount of metal recovery is small and a large amount of tailings are remaining. For the production of glass-ceramic, ceramic, brick and hollow brick, the amount of usage is limited and the cost is high. The application efficiency is also limited. 

Tungsten copper is fused with powder metallurgy by using a certain percentage of copper powder and tungsten powder. Such material combines the advantages of tungsten and copper and is widely used in military materials, electronic packaging materials, electrode materials, electrode materials, etc. With the extension of using time and decline of functional of tungsten copper, it exceeds the application areas and becomes waste.

Zinc tungstate is a kind of tungstate, the formula is ZnWO4. As a photocatalyst, zinc tungstate has the appearance of white powder, and most of the size is of nano-level.

Cesium tungsten bronze (CsxWO₃) is a class of non-stoichiometric oxygen octahedron-specific functional compounds. Because of the structural characteristics of cesium tungsten bronze, it has low resistivity and low temperature superconductivity.

As a transition oxide of tungsten, violet tungsten oxide has a good catalytic effect in the electrode reaction of a novel thin-film solar cell. Due to the high efficiency and low cost of the violet tungsten oxide so that it can be used in a novel thin-film solar cell More extensive.

Crystal refers to a unit structure with a large number of microscopic substances arranged in a regular way according to a certain rule. The arrangement rules and crystal sizes of tungsten oxide can be studied and judged from the size of the structure unit. The crystal size has a very important influence on the material properties of tungsten oxide.

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 the common tungsten oxide photocatalyst, the tungsten oxide composite photocatalyst has more excellent material activity on the photocatalytic performance. The photocatalytic activity of tungsten oxide composite photocatalyst mainly depends on its photocatalytic current-carrying particle separation process.