Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
582764 | Journal of Hazardous Materials | 2008 | 8 Pages |
Abstract
Tungsten trioxide hollow microspheres were prepared by immersing SrWO4 microspheres in a concentrated HNO3 solution, and then calcined at different temperatures. The prepared tungsten oxide samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectra, differential thermal analysis-thermogravimetry, UV-visible spectrophotometry, scanning electron microscopy, N2 adsorption/desorption measurements. The photocatalytic activity of the samples was evaluated by photocatalytic decolorization of rhodamine B aqueous solution under visible-light irradiation. It was found that with increasing calcination temperatures, the average crystallite size and average pore size increased, on the contrary, Brunauer-Emmett-Teller-specific surface areas decreased. However, pore volume and porosity increased firstly, and then decreased. Increasing calcination temperatures resulted in the changes of surface morphology of hollow microspheres. The un-calcined and 300 °C-calcined samples showed higher photocatalytic activity than other samples. At 400 °C, the photocatalytic activity decreased greatly due to the decrease of specific surface areas. At 500 °C, the photocatalytic activity of the samples increased again due to the junction effect of two phases.
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Authors
Jiaguo Yu, Lifang Qi, Bei Cheng, Xiufeng Zhao,