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 degrees C. The obtained nanowires were doped with palladium. The morphology, crystal structure, and H-2 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 H-2 gas at an operating temperature of RT-300 degrees 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 Hz gas at 100 degrees C. The results demonstrated that Pd doping improved the sensor response and lowered the operating temperature at which the sensor response was maximized. (c) 2008 Elsevier B.V. All rights reserved.