Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education), School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China.
Key Laboratory of Bio-based Material Science & Technology (Ministry of Education), College of Material Science and Engineering, Northeast Forestry University, Harbin 150040, China.
Chemosphere. 2023 May;324:138325. doi: 10.1016/j.chemosphere.2023.138325. Epub 2023 Mar 6.
It is desirable but challenging to sense toxic nitrogen dioxide (NO) for it has become one of the most prominent air pollutants. Zinc oxide-based gas sensors are known to detect NO gas efficiently, however, the sensing mechanism and involved intermediates structures remain underexplored. In the work, a series of sensitive materials, including zinc oxide (ZnO) and its composites ZnO/X [X = Cel (cellulose), CN (g-CN) and Gr (graphene)] have been comprehensively examined by density functional theory. It is found that ZnO favors adsorbing NO over ambient O, and produces nitrate intermediates; and HO is chemically held by zinc oxide, in line with the non-negligible impact of humidity on the sensitivity. Of the formed composites, ZnO/Gr exhibits the best NO gas-sensing performance, which is proved by the calculated thermodynamics and geometrical/electronic structures of reactants, intermediates and products. The interfacial interaction has been elaborated on for composites (ZnO/X) as well as their complexes (ZnO- and ZnO/X-adsorbates). The current study well explains experimental findings and opens up a way to design and unearth novel NO sensing materials.
虽然氧化锌（ZnO）基气体传感器已被证实可高效探测 NO 气体，但探测机制及相关中间结构仍有待深入研究。为此，我们采用密度泛函理论对一系列敏感材料（包括 ZnO 及其复合材料 ZnO/X [X = Cel（纤维素）、CN（g-CN）和 Gr（石墨烯）]）进行了全面研究。研究发现，相较于环境中的 O，ZnO 更倾向于吸附 NO，并产生硝酸盐中间产物；同时，ZnO 可化学吸附 HO，这与湿度对灵敏度的显著影响一致。在所形成的复合材料中，ZnO/Gr 表现出最佳的 NO 气敏性能，这一结论可通过对反应物、中间产物和产物的热力学和几何/电子结构计算来证明。我们还详细阐述了复合材料（ZnO/X）及其复合物（ZnO 和 ZnO/X 吸附物）的界面相互作用。本研究很好地解释了实验结果，并为设计和发掘新型 NO 传感材料开辟了道路。
