Ethanol gas sensing using a networked PbO-decorated SnO2 nanowires

PbO-decorated SnO2 nanowires (NWs) were synthesized using a two-step process consisting of thermal evaporation of Sn powders in an oxygen atmosphere and solvothermal decoration of the SnO2 NWs with PbO nanoparticles. Chemiresistive gas sensors were fabricated by deposition of the synthesized PbO-decorated SnO2 NWs onto interdigitated electrodes. The pristine and PbO-decorated SnO2 NW sensors exhibited responses of 24.0 and 60.0 to 200-ppm ethanol at 300 °C, respectively, suggesting that the response of the SnO2 NWs is significantly improved by decorating them with PbO nanoparticles. This result also suggests that the ability of enhancing the gas sensing performance of the original sensor material further is more important than the gas sensing ability of the decorating material itself. The response of the PbO-decorated SnO2 NWs was compatible or higher than those of the SnO2 NWs decorated with other well-known semiconducting metal oxide or noble metal nanoparticles. The response/recovery times of the decorated NWs were shorter than the pristine one, respectively. Both the pristine and PbO-decorated SnO2 NW sensors exhibited selectivity toward ethanol against other volatile organic compounds such as acetone, methanol, benzene, and toluene. The underlying mechanisms for the enhanced sensing performance of the PbO-decorated SnO2 NW sensors toward ethanol was discussed.