Abstract Metal oxides with high-energy facets usually have more active surface sites to facilitate gas adsorption. In this work, the ZnO/graphene composites are synthesized hydrothermally and the morphology of ZnO nanoparticles can be changed from nanorods to nanoplates with the high-energy {0001} polar surface exposed by changing the density of sodium citrate in the reaction. The ZnO{0001}/graphene composites have better sensing properties to NO2 at room temperature (RT). Based on first-principles calculation, the adsorption energy of NO2 on the ZnO{0001} facet is more negative than that on the {01 1 ¯ 0} surface indicating stronger interactions between the former and NO2. Furthermore, the ZnO{01 1 ¯ 0} surface shows semiconducting characteristics, whereas the ZnO{0001} polar surface is metallic. The metallic characteristics promote charge transfer at the interface between ZnO and graphene and enhance the NO2 detection sensitivity.

中文翻译：

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六方氧化锌纳米片/石墨烯复合材料在室温下对 NO2 具有出色的传感性能

摘要 具有高能面的金属氧化物通常具有更多的活性表面位点以促进气体吸附。在这项工作中，ZnO/石墨烯复合材料是水热合成的，并且通过改变反应中柠檬酸钠的密度，可以将 ZnO 纳米颗粒的形态从纳米棒转变为具有高能 {0001} 极性表面的纳米片。ZnO{0001}/石墨烯复合材料在室温 (RT) 下对 NO2 具有更好的传感特性。根据第一性原理计算，NO2 在 ZnO{0001} 面上的吸附能比在 {01 1¯ 0} 面上的更负，表明前者与 NO2 之间的相互作用更强。此外，ZnO{01 1 ¯ 0} 表面显示出半导体特性，而ZnO{0001} 极性表面是金属的。