The Stability of Liquid Hydrocarbon Vapor Sensors Based on SnO2 Thin Films Modified with Various Catalysts

The microstructure, composition, and electrical and gas-sensitive characteristics of sensors based on thin nanocrystalline SnO2 films with various catalysts deposited on the surface (Pt/Pd, Au) and introduced into the bulk (Au, Ni, Co) are investigated in the modes of constant and pulse heating. Atomic force microscopy and laser Raman spectroscopy are used to study micromorphology and structural defects depending on the composition of nanosized films. It is shown that sensors with Au and Co additives introduced into the volume make it possible to detect vapors of liquid hydrocarbons (on the example of aviation kerosene) at a concentration level of 5 ppm (0.1 of permissible exposure limit) and are characterized by increased stability of parameters during testing under prolonged exposure to vapors, as well as in conditions of varying humidity. Sensors with Au and Co additives in volume and deposited onto the film surface ultrathin two-layer Pt/Pd catalysts demonstrate the fastest response after testing.