Based on the experimental reports, Au-decoration on the ZnO nanostructures dramatically increases the electronic sensitivity to H2S gas. In the current study, we computationally scrutinized the mechanism of Au-decoration on a ZnO nanotube (ZON) and the influence on its sensing behavior toward H2S gas. The intrinsic ZON weakly interacted with the H2S gas with an adsorption energy of −11.2 kcal/mol. The interaction showed no effect on the HOMO–LUMO gap and conductivity of ZON. The predicted response of intrinsic ZON toward H2S gas is 6.3, which increases to 78.1 by the Au-decoration at 298 K. The corresponding experimental values are about 5.0 and 80.0, indicating excellent agreement with our findings. We showed that the Au atom catalyzes the reaction 3O2 + 2H2S → 2SO2 + 2H2O. Our calculated energy barrier (at 298 K) is about 12.3 kcal/mol for this reaction. The gap and electrical conductance Au-ZON largely changed by this reaction are attributed to the electron donation and back-donation processes. The obtained recovery time is about 1.35 ms for desorption of generated gases from the surface of the Au-ZON sensor. GRAPHICAL ABSTRACT

中文翻译：

---

用 Au 装饰的 ZnO 纳米管检测硫化氢气体：计算研究和与实验观察的比较

根据实验报告，ZnO 纳米结构上的 Au 装饰显着增加了对 H2S 气体的电子敏感性。在当前的研究中，我们通过计算仔细研究了 ZnO 纳米管 (ZON) 上 Au 修饰的机制及其对 H2S 气体传感行为的影响。本征 ZON 与 H2S 气体的相互作用较弱，吸附能为 -11.2 kcal/mol。相互作用对 ZON 的 HOMO-LUMO 间隙和电导率没有影响。固有 ZON 对 H2S 气体的预测响应为 6.3，在 298 K 时通过 Au 装饰增加到 78.1。相应的实验值约为 5.0 和 80.0，表明与我们的研究结果非常吻合。我们表明金原子催化反应 3O2 + 2H2S → 2SO2 + 2H2O。我们计算出的能量势垒（298 K）约为 12。该反应为 3 kcal/mol。这种反应很大程度上改变了Au-ZON的间隙和电导，这归因于电子捐赠和回馈过程。所获得的恢复时间约为 1.35 ms，用于从 Au-ZON 传感器表面解吸产生的气体。图形概要