Tungsten Trioxide as a Visible Light Photocatalyst for Volatile Organic Carbon Removal

Tungsten trioxide (WO(3)) has been demonstrated to possess visible light photoactivity and presents a means of overcoming the UV-light dependence of photocatalysts, such as titanium dioxide. In this study, WO(3) nanostructures have been synthesised by a hydrothermal method using sodium tungstate (Na(2)WO(4)·2H(2)O), sulphate precursors and pH as structure-directing agents and parameters, respectively. By altering the concentration of the sulphate precursors and pH, it was shown that different morphologies and phases of WO(3) can be achieved. The effect of the morphology of the final WO(3) product on the visible light photoactivity of ethylene degradation in the gas phase was investigated. In addition, platinum (Pt) was photodeposited on the WO(3) structures with various morphologies to enhance the photocatalytic properties. It was found that the photocatalytic properties of the WO(3) samples greatly depend on their morphology, chemical composition and surface modification. WO(3) with a cuboid morphology exhibited the highest visible light photoactivity compared to other morphologies, while adding Pt to the surface improved the performance of certain WO(3) structures.