Facile synthesis of SnO2-ZnO core-shell nanowires for enhanced ethanol-sensing performance

The design of core-shell heteronanostructures is powerful tool to control both the gas selectivity and the sensitivity due to their hybrid properties. In this work, the SnO2-ZnO core-shell nanowires (NWs) were fabricated via two-step process comprising the thermal evaporation of the single crystalline SnO2 NWs core and the spray-coating of the grainy polycrystalline ZnO shell for enhanced ethanol sensing performance. The as-obtained products were investigated by X-ray diffraction, scanning electron microscopy, and photoluminescence. The ethanol gas-sensing properties of pristine SnO2 and ZnO-SnO2 core-shell NW sensors were studied and compared. The gas response to 500 ppm ethanol of the core-shell NW sensor increased to 33.84, which was 12.5-fold higher than that of the pristine SnO2 NW sensor. The selectivity of the core-shell NW sensor also improved. The response to 100 ppm ethanol was about 14.1, whereas the response to 100 ppm liquefied petroleum gas, NH3, H-2, and CO was smaller, and ranged from 2.5 to 5.3. This indicates that the core-shell heterostructures have great potential for use as gas sensing materials. (C) 2013 Elsevier B.V. All rights reserved.