X射线光电子能谱
物理吸附
化学吸附
氢
二硫化钨
单层
密度泛函理论
化学
钨
吸附
材料科学
化学物理
物理化学
纳米技术
计算化学
化学工程
有机化学
工程类
冶金
作者
Tomoya Minezaki,Péter Krüger,Fatima Ezahra Annanouch,Juan Casanova-Cháfer,Aanchal Alagh,Ignacio J. Villar‐García,Virgínia Pérez-Dieste,Eduard Llobet,Carla Bittencourt
出处
期刊:Sensors
[Multidisciplinary Digital Publishing Institute]
日期:2023-05-10
卷期号:23 (10): 4623-4623
被引量:1
摘要
Nanostructured tungsten disulfide (WS2) is one of the most promising candidates for being used as active nanomaterial in chemiresistive gas sensors, as it responds to hydrogen gas at room temperature. This study analyzes the hydrogen sensing mechanism of a nanostructured WS2 layer using near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) and density functional theory (DFT). The W 4f and S 2p NAP-XPS spectra suggest that hydrogen makes physisorption on the WS2 active surface at room temperature and chemisorption on tungsten atoms at temperatures above 150 °C. DFT calculations show that a hydrogen molecule physically adsorbs on the defect-free WS2 monolayer, while it splits and makes chemical bonds with the nearest tungsten atoms on the sulfur point defect. The hydrogen adsorption on the sulfur defect causes a large charge transfer from the WS2 monolayer to the adsorbed hydrogen. In addition, it decreases the intensity of the in-gap state, which is generated by the sulfur point defect. Furthermore, the calculations explain the increase in the resistance of the gas sensor when hydrogen interacts with the WS2 active layer.
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