Tungsten oxide nanopowders and nanorods prepared by a modified plasma arc gas condensation technique

Tungsten oxide nanopowders and nanorods were synthesized by using a modified plasma arc gas condensation technique that involved the introduction of a mixed gas with controllable partial O2 pressure into a gas condensation system. Experimental results showed that yellow and blue tungsten oxide nanopowders, prepared under an Ar to O2 ratios of 1: 1 and 100: 1, exhibited a major WO3 phase and W19O55 phase, respectively. The nanopowders grew into W5O14-phase nanorods along the [001] direction when H2 was used as the reduction gas.