CuO-ZnO花状纳米结构复合材料设计、合成及气敏特性研究

Design,Synthesis and Gas Sensing Properties of CuO-ZnO Flower-Like Nanostructures

采用一步水热法制备CuO-ZnO花状纳米结构复合材料.采用X射线衍射仪(XRD)、能谱仪(EDX)及扫描电镜(SEM)对制备的材料进行结构及形貌表征,并使用静态配气法测试CuO-ZnO花状纳米结构复合材料对甲醛的气敏性能.结果表明:适量引入CuO可显著改善ZnO材料的气敏特性.200℃的工作温度下,掺杂摩尔分数为5%CuO的ZnO花状纳米结构材料对体积分数为1×10-5甲醛的灵敏度最高,为8.1,是未掺杂ZnO的2.3倍,同时具有良好的循环稳定性和选择性.最后,对CuO掺杂的气敏机理进行了讨论,其气敏性能的提高归因于在ZnO与CuO接触面形成了p-n异质结及CuO的催化特性.

The CuO-ZnO flower-like nanostructures were successfully synthesized by using a facile one-step hydrothermal process followed by calcination.The structural features were mainly characterized by X-ray diffraction(XRD),energy dispersive X-ray spectroscopy(EDX)and scanning electron microscopy(SEM).The gas sensitivity of CuO-ZnO flower-like nanostructure composites to formaldehyde was tested by static gas distribution method.The results show that the gas sensing properties of ZnO meterials can be significantly improved by introducing appropriate amount of CuO.Especially,the molar percentage 5%CuO-ZnO microflower sensor exhibited the highest responses compared with others at a relatively lower operating temperature of 200℃,which is 8.1,2.3 times that of undoped ZnO.In addition,good reproducibility and selectivity to formaldehyde were also obtained,indicating the formation of CuO-ZnO heterojunction in favor of improving the sensing properties.Finally,the sensing enhancement mechanism of the CuO-ZnO microflowers was also discussed.The improvement of gas sensing performance is attributed to the formation of p-n heterojunction at the interface between ZnO and CuO and the catalytic properties of CuO.