Gas Sensing Properties Of Nano-Zinc Oxide Doped With Graphene

In this paper,two kinds of different nanostructures of zinc oxide nanoparticles and zinc oxide nanorods were prepared by sol-gel method and hydrothermal method respectively.The nanorod structure of zinc oxide was doped with graphene powder.We use the scanning electron microscopy and X-ray diffraction to characterize the samples.It can be seen by SEM test,we have obtained the ZnO nanoparticles with the diameter between 40-80 nm by sol-gel method,and the ZnO nanorods with the diameter between50-100 nm by hydrothermal method.Their growth morphology is very consistent.In the gas sensitivity test,we tested the best working temperature of the gas sensor to 50 ppm ethanol gas,in which the gas sensor was based on zinc oxide nanoparticles.The results showed that the optimum working temperature of the sensor was 350 ℃,and the response value was up to 63.1%.Then we tested the relative sensitivity of 50 ppm methanol,carbon monoxide,ethylene glycol and ethanol at350 ℃,respectively.The relative sensitivities were 11.7%,37.2%,55.1% and 63.1%,respectively.The corresponding value of ethanol for the sensor based on zinc oxide nanorods was 70.2% higher than that of zinc oxide nanoparticles,the best working temperature was decreased,and the optimum working temperature of 50 ppm ethanol was 325 ℃.The optimal working temperature of 50 ppm ethanol gas by gas sensor based on Zinc oxide nanoparticles doped graphene is also 325 ℃,but the response value is greatly improved to 78%.The gas sensitivity test of methanol,carbon monoxide,ethylene glycol and ethanol showed that the relative sensitivity of each gas were 15.3%,41.1%,62.1%,78% respectively,compared with zinc oxide nanoparticles.