Effect of SiO2 Doping on Growth Retardation of WO3 Nanoplate

Abstract

Tungsten oxide (WO3) is recently recognized as one of the most widely studied gas sensitive ceramics. To maintain good thermal stability at moderate operating temperature, the gas sensitive materials were typically heated at several hundreds degree Celsius. Such treatment caused grain growth, resulting to reduction of specific surface area which is considered to be one of the important properties determining gas sensor's performance. In this present work, grain growth of the WO3 nanoplate was retarded by incorporation of silica (SiO2) particle. To obtain homogeneous structure, the SiO2 was incorporated by mixing tetraethyl orthosilicate into the W precursor during precipitation of the tungsten oxide. It was found that the SiO2 dramatically retarded the particle growth, preserved the nanoplate structure, and resulted to more porous WO3 powder. The effect was very significant when the powders were calcined at high temperatures.