【作者】 徐甲强； 薛正刚；

【Author】 Jiaqiang Xu;zhenggang xue;NEST Lab,Department of Chemistry,College of Science,Shanghai University;

【机构】 上海大学理学院化学系NEST实验室；

【摘要】 暴露晶面对催化反应的效率和选择性都有重要的影响,也可调控氧化锌的气体性能。因此,我们以六亚甲基四胺(HMT)和尿素为还原剂,通过水热法分别制备了暴露晶面分别为(0001)和(1010)的ZnO纳米片。表征结果显示,两种多孔薄片的比表面积均约7.5m~2/g,厚度约100纳米,直径约5微米,孔径几十纳米。然而,它们的暴露晶面分别为(0001)和(1010)。气敏测试结果表明:暴露(0001)晶面的ZnO纳米片有更好的气敏性能。这归因于(0001)晶面上存在大量的氧空位缺陷和不饱和悬挂键,这有利于气体分子在晶面上的吸附。第一性原理对不同暴露晶面ZnO的吸附能计算的结果对晶面依赖的气敏性能给予了很好的解释。更多还原

【Abstract】 Exposed planes of ZnO have a crucial impact on the gas sensing.Therefore,porous hexagonal ZnO nanosheets were prepared by a hydrothermal method and the exposed planes of(0001)and(1010) were controlled by HMT and urea.The characterization results show that both the porous nanosheets have a near specific surface area about 7.5 m2/g,thickness about 100 nm,diameter about 5urn and pore size of tens of nanometers.However,their dominating exposed crystal facets are(0001)and(1010),respectively.When employed them as sensing materials in gas sensors,porous ZnO nanosheets with dominating exposed(0001) facet exhibit a superior sensitivity.The enhanced gas response is attributed to a large amount of oxygen vacancy defects and unsaturated dangling bonds existing in the ZnO nanosheets with exposed crystal facet(0001),which is favorable for the adsorption of gas molecular on the sensor surface.Finally,the calculation of the chemisorption energy of oxygen on ZnO crystal facets also proves the reactive-facet-enhanced gas sensitivity.更多还原