Electrostatic sprayed SnO2 and Cu-doped SnO2 films for H2S detection

This paper presents the ability of electrostatic sprayed tin oxide (SnO2) and tin oxide doped with copper oxide (1, 2, and 4 at.% Cu) films to detect different pollutant gases, i.e., H2S, SO2, and NO2. The influence of a copper oxide dopant on the SnO2 morphology is studied using scanning electron microscopy (SEM) technique, which reveals a small decrease in the porosity and particle size when the amount of dopant is increased. The sensing properties of the SnO2 films are greatly improved by doping, i.e., the Cu-doped SnO2 films have large response to low concentration (10 ppm) of H2S at low operating temperature (100 °C). Furthermore, no cross-sensitivity to 1 ppm NO2 and 20 ppm SO2 is observed. Among the studied films, the 1 at.% Cu-doped SnO2 layer is the most sensitive in the detection of all the studied gases.