Highly sensitive H2S gas sensor containing simultaneously UV treated and self-heated Ag-SnO2 nanoparticles

A gas sensor to detect H2S gas based on SnO2 nanorods (NRs) and Ag doped SnO2 nanoparticles (NPs) was fabricated by growing SnO2 NRs on an interdigitated Au substrate and spin coating Ag doped SnO2 NPs on the NRs’ surface. The morphology, chemical, optical, and electrical properties of this nanostructure were examined using FESEM, EDAX, XRD, PL and absorption spectroscopy. The fabricated sensor was further enhanced by doping the SnO2 NPs with Ag as well as utilizing an innovative method of simultaneous exposure to UV illumination and self-heating. The proposed design has proven to reduce the destructive effect of humidity due to its photocatalytic properties. This unique nanostructure design enhanced the sensing response of the device from 2.7 to 8 (in the detection range of 500 ppb-10 ppm). This improvement caused by an increase of the electron injection on the NPs’ interfaces and a multiplication of the available active sites on which H2S gas is trapped. In addition, the sensor’s response and recovery time toward 10 ppm H2S gas increased from 11 and 14 s to 5 and 8 s respectively. The sensor’s cross-sensitivity toward C6H6, C2H5OH, CO2, and NH3 was also examined to determine the selectivity.