Monolayer Ti2CO2: A Promising Candidate for NH3 Sensor or Capturer with High Sensitivity and Selectivity

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• 作者：Xue-fang Yu ; Yan-chun Li ; Jian-bo Cheng ; Zhen-bo Liu ; Qing-zhong Li ; Wen-zuo Li ; Xin Yang ; Bo Xiao
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：June 24, 2015
• 年：2015
• 卷：7
• 期：24
• 页码：13707-13713
• 全文大小：381K
• ISSN：1944-8252

文摘

Ti₂C is one of the thinnest layers in MXene family with high potential for applications. In the present study, the adsorption of NH₃, H₂, CH₄, CO, CO₂, N₂, NO₂, and O₂ on monolayer Ti₂CO₂ was investigated by using first-principles simulations to exploit its potential applications as gas sensor or capturer. Among all the gas molecules, only NH₃ could be chemisorbed on Ti₂CO₂ with apparent charge transfer of 0.174 e. We further calculated the current鈥搗oltage (I鈥?i>V) relation using the nonequilibrium Green鈥檚 function (NEGF) method. The transport feature exhibits distinct responses with a dramatic change of I鈥?i>V relation before and after NH₃ adsorption on Ti₂CO₂. Thus, we predict that Ti₂CO₂ could be a promising candidate for the NH₃ sensor with high selectivity and sensitivity. On the other hand, the adsorption of NH₃ on Ti₂CO₂ could be further strengthened with the increase of applied strain on Ti₂CO₂, while the adsorption of other gases on Ti₂CO₂ is still weak under the same strain, indicating that the capture of NH₃ on Ti₂CO₂ under the strain is highly preferred over other gas molecules. Moreover, the adsorbed NH₃ on Ti₂CO₂ could be escapable by releasing the applied strain, which indicates the capture process is reversible. Our study widens the application of monolayer Ti₂CO₂ not only as the battery material, but also as the potential gas sensor or capturer of NH₃ with high sensitivity and selectivity.