SnO2 were synthesized by hydrothermal treatment of colloidal hydrous tin oxide at 160-200 oC for 48 hrs. The colloidal hydrous tin oxide precursor was prepared by mixing 0.188 M Na2SnO3 • 3H2O solution with 0.35 M NaOH solution followed by the addition of absolute ethanol at ambient temperature under vigorous stirring until the white suspension was completely formed. XRD, SEM and TEM analyses revealed that SnO2 clusters of 2.2 ± 0.15 μm in size consisting of tetragonal-shaped, single crystalline SnO2 nanorods of 276 ± 30 nm wide and 1.33 ± 0.15 μm long was obtained at 200 oC while SnO2 nanoparticles of 228 ± 81 nm in size consisting of 6.9 ± 1.1 nm crystals were obtained at 160-180 oC. Some single crystalline elongated particles of 224 ± 40 nm wide and 584 ± 126 nm long were also formed at 180 oC. Gas-sensing study of the screen-printed SnO2 nanorod sensor revealed that the sensor had good selectivity toward H2S as it showed high response to 10 ppm H2S, only moderate response to 10 ppm NO2, and very low responses to 1000 ppm CO and 1000 ppm SO2. The sensor showed good response to 0.3 ppm H2S at relatively low operating temperature of 300 oC with the response and recover times of ~ 1 and 3- 4 minutes, respectively.

Keywords: SnO2, Nanorod, Hydrothermal, Gas sensor, Hydrogen sulfide.