Influence of precious metals on gas sensing properties of tungsten oxide, prepared by the sol-gel method

Abstract

The effect of Pd and Ag additives (0,5-1,5 % by weight) on the crystal structure and gas sensitivity of tungsten oxide WO₃ prepared by sol-gel method, has been studied. A large increase (more than 3-4 times) of the sensitivity to CO and CH₄ as compared with the starting WO₃, and the shift of the high sensitivity band to low temperatures (from 120 °C) have been established. Response values to 300 ppm CO and 9,8 ppm CH₄ in the air have been 350 and 320 %, respectively (170 °C).