SYNTHESIS OF CARBON NANOTUBES/SNO2 CORE-SHELL NANOWIRES AND THEIR GAS SENSITIVITY TO ALCOHOL

In this paper, we report the synthesis of CNTs/SnO2 core-shell composite materials by a novel method. It shows that the SnO2 nucleation and growth on the outer wall of CNTs result in the formation of core-shell structure nanowires with uniform layer of parcels. We tested the gas sensitivity of the CNTs/SnO2 composites to ethyl alcohol by static method, and found that the introduction of CNTs in the SnO2 composite materials results in a decrease in their optimum operating voltage, with the optimum at V-H = 3.5 V, and an increase in their gas sensitivity. We also found that as the operating voltage increases, the gas sensing of the CNTs/SnO2 composites decreases after at first increasing with the alcohol concentration increases. The sensitivity of the composites to alcohol gradually increases and tends to reach a constant finally. Moreover, the sensitivity reaches the maximum at concentration level of 800 ppm ethyl alcohol.