Detection of Carbon Monoxide in Humid Air with Double-Layer Structures Based on Semiconducting Metal Oxides and Silicalite

Abstract

Double-layer structures based on gas-sensitive semiconducting metal oxides and silicalite-1 were tested in detection of carbon monoxide in humid air. Pure tin dioxide and that modified with antimony and palladium served as materials of the sensitive layer. Upon deposition of a silicalite-1 layer on SnO₂ and SnO₂/PdO_x, the signal for CO in dry air at room measurement temperature (T = 25°C) grows, but an increase in the air humidity results in that the sensor sensitivity fully disappears. Raising the measurement temperature to 100°C makes weaker the adverse effect of the humidity. The double-layer structure containing the SnO₂(Sb)/PdO_x nanocomposite is characterized by the most stable sensor signal that is independent of the air humidity within the range RH = 4‒65%.