Publication: Formation of nanostructured tungsten oxide by anodisation process
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Date
2009-05-01
Authors
Abd Samad, Nur Azimah
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Abstract
Today, the industrial is severely affecting the environment cause an environmental problem such as water pollution, air pollution, and radioactive contamination etc. Therefore, there is an urgent need for the researchers to invent a material to degrade the pollutant. Photocatalyzer as an n-type semiconductor has the ability to degrade the pollutant. Nowadays, titania is widely used as the photocatalyzer. But, due to some drawback of titania, formation of nanostructure tungsten oxide has been studied. The formation of tungsten oxide (WO) nanostructure by anodization was studied in aqueous electrolyte (Na2SO4). In order to get a good control of the dimension of the porous nanostructuresd WO, in particular to get tubular structure, various parameters were investigated such as anodizing time, fluoride content, variation of pH, variation of potentials and the use of non-aqueous electrolyte. Under certain optimized electrochemical condition (40 V,
0.7 g fluoride, 15 minutes, pH 6), nanotubular tungsten oxide was successfully formed. The length of the nanotubular was found to be affected by pH and anodizing time whereby longest tube were produced in tungsten anodized for 15 minutes in electrolyte with pH 3. Besides that, fluoride content and potential was also found as important factors affecting the surface morphology of the formed tungsten oxide. 40 V and 0.7 g of fluoride content is a sufficient potential and fluoride content to develop tube like structure. Under UV light, methyl orange discoloration was observed after 2 hours. After 2 hours, the color of methyl orange dye was change to almost colorless indicating tungsten oxide is effective photocatalyzer.