Microstructure and H2 gas sensing properties of undoped and Pd-doped SnO2 nanowires

Tin oxide (SnO2) nanowires with a tetragonal structure were synthesized by thermal evaporation of tin grains at 900 °C. The obtained nanowires were doped with palladium. The morphology, crystal structure, and H2 gas sensing properties of undoped and Pd-doped SnO2 nanowires were investigated. SnO2 nanowires were approximately 30–200 nm in diameter and several tens of micrometers in length. Gas sensors based on undoped, 0.8 wt% Pd-doped, and 2 wt% Pd-doped SnO2 nanowires were fabricated. These SnO2 nanowire gas sensors showed a reversible response to H2 gas at an operating temperature of RT—300 °C. The sensor response increased with increasing Pd concentration. The 2 wt% Pd-doped SnO2 nanowire sensor showed a response as high as 253 for 1000 ppm H2 gas at 100 °C. The results demonstrated that Pd doping improved the sensor response and lowered the operating temperature at which the sensor response was maximized.