Fabrication of Tungsten Oxide Nanostructure by Sol-Gel Method

In this work, we present the effects of mixing sequence of sodium tungstate and nitric acid, as well as the aging duration on the formation of tungsten oxide by sol-gel method. Increase of the aging duration allows the formation of uniform platelet structure where no structure could be detected at 1 aging day while uniform platelet structure could be detected at 30 days. Hydrated tungsten oxide platelets of 1-1.θ зm could be formed by mixing sodium tungstate into nitric acid (sample labeled as W-A) which could be reduced significantly in size to 200-600 nm by changing the mixing sequence to drop nitric acid into sodium tungstate (sample labeled as A-W). Crystalline hydrated tungsten oxides were obtained for both samples where W-A sample shows better degree of crystallinity. Room temperature hydrogen gas sensing property was successfully detected by both samples where A-W sample demonstrates ∼2.5 times higher sensor response to hydrogen gas compared to W-A sample.