Dip-coating decoration of Ag(2)O nanoparticles on SnO(2) nanowires for high-performance H(2)S gas sensors

SnO(2) nanowires (NWs) are used in gas sensors, but their response to highly toxic gas H(2)S is low. Thus, their performance toward the effective detection of low-level H(2)S in air should be improved for environmental-pollution control and monitoring. Herein, Ag(2)O nanoparticle decorated SnO(2) NWs were prepared by a simple on-chip growth and subsequent dip-coating method. The amount of decorated Ag(2)O nanoparticles on the surface of SnO(2) NWs was modified by changing the concentration of AgNO(3) solution and/or dipping times. Gas-sensing measurements were conducted at various working temperatures (200–400 °C) toward different H(2)S concentrations ranging within 0.1–1 ppm. The selectivity of Ag(2)O-decorated SnO(2) NW sensors for ammonia and hydrogen gases was tested. Results confirmed that the Ag(2)O-decorated SnO(2) NW sensors had excellent response, selectivity, and reproducibility. The gas-sensing mechanism was interpreted under the light of energy-band bending by sulfurization, which converted the p–n junction into n–n, thereby significantly enhancing the sensing performance.