Temperature-controlled resistive sensing of gaseous H2S or NO2 by using flower-like palladium-doped SnO2 nanomaterials.

Palladium-doped SnO2 nanomaterials, with palladium in fractions from 0 to 10 mol% were hydrothermally synthesized and characterized by XRD, FESEM, TEM, and XPS. Their gas sensing properties were studied in two temperature ranges of 75-95 °C and 160-210 °C. The sensor using 5 mol% Pd-doped SnO2 exhibits temperature-dependent sensing property. NO2 can be detected at 80 °C, while H2S is preferably detected at 180 °C. The response to 10 ppm H2S is 50 times higher than that of the undoped sample. Its detection limit is 500 ppb. For NO2, the sensor exhibited strong response and a lower detection limit of 20 ppb. In view of the selective detection of H2S and NO2 by regulating the temperature, palladium-doped SnO2 has great prospects in the detection of H2S and NO2. Graphical abstract Schematic of the gas sensing mechanism of the S-5% Pd doped SnO2.