Monoclinic tungsten trioxide nanoflake may be prepared by chemical precipitation method.
Chemical Precipitation Method to Prepare Monoclinic Tungsten Trioxide Nanoflake
The chemical reagents used are all analytical reagents (AR) and not purified before use.
1. Weigh 3.0g Na2WO3 and 0.005g CTAB (cetyl trimethyl ammonium bromide), dissolved in 10mL distilled water. Slowly drop 3mL of this solution into 5mL 3mol•L-1 HCL and stir for 1 ~2h.
2. After centrifugal settling of the reacted solution, wash it repeatedly with distilled water and acetone, dried the obtained precipitate in an oven at 80°C to obtain precursor.
3. Put the precursor in muffle furnace, and calcined at 300°C for 3h to obtain light yellow powder.
Product Structure and Property Characterization
The phase was determined by X-ray diffraction (XRD). The morphology was observed with X-650 field emission scanning electron microscope (FESEM). The optical properties were determined by UV SP-752 visible spectrophotometer.
The band gaps of as-prepared products were determined by UV-Vis absorption spectra. Compared with orthorhombic WO3, the band gap of monoclinic tungsten trioxide was lower. So, the photocatalytic activity of monoclinic WO3 was higher due to more electron-hole pairs.
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