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.