Sensors based on mesoporous SnO₂-CuWO₄ with high selective sensitivity to H₂S at low operating temperature

Development of new sensitive materials by different synthesis routes in order to emphasize the sensing properties for hazardous H₂S detection is one of a nowadays challenge in the field of gas sensors. In this study we obtained mesoporous SnO₂-CuWO₄ with selective sensitivity to H₂S by an inexpensive synthesis route with low environmental pollution level, using tripropylamine (TPA) as template and polyvinylpyrrolidone (PVP) as dispersant/stabilizer. In order to bring insights about the intrinsic properties, the powders were characterized by means of a variety of complementary techniques such as: X-Ray Diffraction, XRD; Transmission Electron Microscopy, TEM; High Resolution TEM, HRTEM; Raman Spectroscopy, RS; Porosity Analysis by N₂ adsorption/desorption, BET; Scanning Electron Microscopy, SEM and X-ray Photoelectron Spectroscopy, XPS. The sensors were fabricated by powders deposition via screen-printing technique onto planar commercial Al₂O₃ substrates. The sensor signals towards H₂S exposure at low operating temperature (100°C) reaches values from 10⁵ (for SnWCu600) to 10⁶ (for SnWCu800) over the full range of concentrations (5-30ppm). The recovery processes were induced by a short temperature trigger of 500°C. The selective sensitivity was underlined with respect to the H₂S, relative to other potential pollutants and relative humidity (10-70% RH).