Growth of micron-sized tubes of tungsten oxide

Micron-sized tubes of tungsten oxide have been grown in a catalyst-free reaction by heating tungsten wires in a humid argon flow. They were systematically characterized with different kinds of surface analysis means. The tubes were 1-5 mu m in diameter and similar to 10 mu m in length. Depending on the fabrication conditions, they were composed of either monoclinic W18O49 or hexagonal tungsten trioxide (h-WO3). These tungsten oxide tubes are considered to have resulted from the lateral coalescence of tungsten oxide nanorods. (C) 2007 Elsevier B.V. All rights reserved.