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 SnO_2.