Direct Hydrothermal Precipitation of Pyrochlore-Type Tungsten Trioxide Hemihydrate from Alkaline Sodium Tungstate Solution

Solvothermal synthesis of pyrochlore-type cubic tungsten trioxide hemihydrate and high photocatalytic activity

“…Li and colleagues believed that the precipitation of c-WO 3 Á0.5H 2 O occurred mainly in the pH range of 7.0-8.5. 30 Investigations have shown that the pH can affect the existing form of tungstate ions, and the various forms of tungstate ions existing are considered to be the precursors of tungsten oxides with different crystal structures. In order to know the effect of pH, pH change experiments were carried out by adjusting the amount of hydrochloric acid.…”

“…Li and colleagues believed that the precipitation of c-WO 3 Á0.5H 2 O occurred mainly in the pH range of 7.0-8.5. 30 Investigations have shown that the pH can affect the existing form of tungstate ions, and the various forms of tungstate ions existing are considered to be the precursors of tungsten oxides with different crystal structures. In order to know the effect of pH, pH change experiments were carried out by adjusting the 22 Su and co-workers respectively used equal amounts of L(+)-tartaric acid and citric acid as assistant agents and adjusted the initial pH of the solution to 1 using hydrochloric acid, and accordingly to obtain the hexagonal phase and orthorhombic phase of tungsten trioxide.…”

“…But few reports on the photocatalytic properties of tungsten trioxide hydrates have been reported, particularly for c-WO 3 Á0.5H 2 O. There are some articles on their synthesis only, 22,[27][28][29][30] but studies on the photocatalytic properties of c-WO 3 Á0.5H 2 O have been neglected. Therefore, it is necessary to study the synthesis method of c-WO 3 Á0.5H 2 O and its photocatalytic property.…”

Template and surfactant free synthesis of hierarchical WO3·0.33H2O via a facile solvothermal route for photocatalytic RhB degradation

“…Furthermore, tungstate anions are considered as a precursor of tungsten oxide. [40][41][42][43] The solubility of sodium tungstate would then directly affect the state of the tungstate anions. This is the reason the hexagonal phase of WO 3 •0.33H 2 O was obtained when using acetone as solvent, and the orthorhombic phase of WO 3 •0.33H 2 O was obtained in the water and acetone reaction system.…”