Oxygen adsorption on ZrO2-loaded SnO2 gas sensors in humid atmosphere

Abstract

Oxygen adsorption on the surface of particles plays a key role in gas sensing for SnO2-based resistive-type gas sensors in a humid atmosphere. In this study, we added an extremely small amount of ZrO2 on the SnO2 surface to activate oxygen adsorption and enhance the sensor response of a SnO2-based gas sensor in a humid atmosphere. We evaluated the oxygen adsorption properties and sensor response to 200 ppm H2 in a humid atmosphere (96%) based on variations in the measured electrical resistance. The adsorption of O− and O2− ions was activated by a small loading (0.033 mol%) of ZrO2, and the resulting ZrO2–SnO2 composite nanoparticles were in the deep electron-depleted state. This led to a high sensor response of ZrO2–SnO2 to H2 in a humid atmosphere. The results demonstrate that surface modification using an extremely small amount of ZrO2 was effective in improving the response of a SnO2-based gas sensor in a humid atmosphere.