The nanosized WO₃ powders have been prepared by method of gas-liquid reaction between aqueous Na 2WO 4 and HCl in this work. The NMR, XRD and XPS techniques were used to characterize the catalyst. And the effects of calcination temperature and ethanol concentration on the particle size and photocatalytic activity of the photocatalysts were discussed in detail. The photoelectrochemical actions of WO₃ powders were studied by cyclic-voltammetry method as well. It was showed that gas-liquid reaction method is a simple method for nano-sized WO₃ powder preparation. The size of WO₃ powders is less than 100 nm. The beneficial effects of ethanol concentration on controlling WO₃ powder size and particle dispersity were found, and the negative effects of higher calcination temperature on that were also indicated.

Key words: nanosized WO₃ powder, photocatalytic activity, photocatalyst preparation