氢
化学物理
机制(生物学)
曲面(拓扑)
材料科学
密度泛函理论
化学
纳米技术
计算化学
物理
几何学
量子力学
数学
有机化学
作者
Xiaohua Wang,Xuemei Yang
出处
期刊:Surface Science
[Elsevier]
日期:2022-02-23
卷期号:721: 122064-122064
被引量:13
标识
DOI:10.1016/j.susc.2022.122064
摘要
• Two generally accepted and well-established gas sensing mechanisms for metal oxide are oxygen-adsorption and oxygen-vacancy mechanism. In order to clarify the real mechanism, careful DFT simulations were carried out to investigate the interactions between small molecules (including H 2 , O 2 , and H 2 O) with SnO 2 (110) surface as a typical example. With respect to the previous assumptions, the mechanism of metal oxide sensing towards hydrogen gas still remains controversial. Two H 2 sensing mechanisms for metal oxide, oxygen-adsorption and oxygen-vacancy mechanism are generally accepted. In order to clarify the mechanism cleanly and take SnO 2 (110) surface as a typical example, careful DFT simulations were carried out to investigate the interactions between small molecules (including H 2 , O 2 , and H 2 O) and metal oxide. We found that the dissociation of H 2 can spontaneously take place on the SnO 2 (110) surface. Based on the energy difference and transition state searching, the main barrier of H 2 sensing lied in the dissociation of O 2 on the surface. If there exists oxygen-vacancy on the surface, it would contribute to largely reduce the energy barrier of dissociation process of O 2 . Besides, the band alignments for different adsorption states were indicated. It suggested that the H 2 sensing mechanism could be a mixed one including both oxygen-adsorption and oxygen-vacancy mechanism. At the end of this work, a modified band alignment as well as assumptive resistance change was provided, which was in line with previous experiment work. This work not only provided strong theoretical supports to previous assumptions, but also lightened the routes to design more outstanding H 2 sensors. Two generally accepted and well-established gas sensing mechanisms for metal oxide are oxygen-adsorption and oxygen-vacancy mechanism. In order to clarify the real mechanism, careful DFT simulations were carried out to investigate the interactions between small molecules (including H 2 , O 2 , and H 2 O) with SnO 2 (110) surface as a typical example.
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