Flame aerosol synthesis of tungsten trioxide powder: Particle morphology control and photodegradation activity under visible light irradiation

• Tungsten trioxide powder was obtained by facile flame-aerosol method.
• Different morphologies were observed by adjusting precursor concentration.
• Spherical particles with larger specific surface show the best adsorption capability.
• Polyhedron particles with {001} and {111} facets show best photocatalytic activity.

Tungsten trioxide powders of different morphologies are synthesized through one-step flame aerosol route by adjusting precursor concentration. X-ray diffraction indicates that the powders are γ-WO3. Scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy are used to characterize the detailed structure and near surface chemical compositions. At very low precursor concentration of 0.25 mol/L, the WO3 particles are sphere, but when that approaches 1.00 mol/L a large amount of crystalline polyhedron composed of two {001} and eight {111} facets are widely observed. The formation mechanism of γ-WO3 within the high temperature environment is discussed, along with the impact of precursor concentration on particle morphology. In addition, during the methylene blue degradation, the spherical particles show the best adsorption capability due to its relatively larger specific surface area, while polyhedron particles present better photocatalytic performance relying on its {001} and {111} facets of high activity.

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