Elger Ann-Kathrin, Hess Christian
Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, 64287, Darmstadt, Germany.
Angew Chem Int Ed Engl. 2019 Oct 14;58(42):15057-15061. doi: 10.1002/anie.201908871. Epub 2019 Sep 12.
SnO is the most widely used metal oxide gas-sensing material but a detailed understanding of its functioning is still lacking despite its relevance for applications. To gain new mechanistic insight into SnO gas sensors under working conditions, we have developed an operando approach based on combined UV/Vis, Raman, and FTIR spectroscopy, allowing us for the first time to relate the sensor response to the concentration of oxygen vacancies in the metal oxide, the nature of the adsorbates, and the gas-phase composition. We demonstrate with the example of ethanol gas sensing that the sensor resistance is directly correlated with the number of surface oxygen vacancies and the presence of surface species, in particular, acetate and hydroxy groups. Our operando results enable an assessment of mechanistic models proposed in the literature to explain gas sensor operation. Owing to their fundamental nature, our findings are of direct relevance also for other metal oxide gas sensors.
SnO是应用最为广泛的金属氧化物气敏材料，但尽管其与实际应用密切相关，人们对其工作原理仍缺乏深入了解。为了在工作条件下获得对SnO气敏传感器的新的机理认识，我们开发了一种基于紫外/可见光谱、拉曼光谱和傅里叶变换红外光谱联用的原位方法，首次使我们能够将传感器响应与金属氧化物中氧空位的浓度、吸附质的性质以及气相组成联系起来。我们以乙醇气敏为例证明，传感器电阻与表面氧空位的数量以及表面物种（特别是醋酸根和羟基）的存在直接相关。我们的原位研究结果能够对文献中提出的解释气敏传感器工作的机理模型进行评估。由于其基础性，我们的发现对其他金属氧化物气敏传感器也具有直接的相关性。
