The phosgene gas sensing properties of experimentally produced 2D titanium carbide MXenes with surface terminations (Ti₂CT₂: T = F⁻, O⁻, OH⁻) are studied by first‐principles calculations. The effect of Ti and C vacancy defects, which are frequently created in synthesizing MXenes, on the structural, mechanical, electronic, and gas adsorption properties are studied to analyze the phosgene gas sensing performance of Ti₂CT₂ MXenes. Pristine and defective Ti₂C, Ti₂CF₂, and Ti₂C(OH)₂ show metallicity, making them ideal for gas sensing. Ti (C) vacancy defects in Ti₂CO₂, Ti₂CF₂, and Ti₂C(OH)₂ cause an increase (decrease) in work function, resulting in enhanced interaction between the MXene surface and a gas molecule. When a phosgene gas molecule is exposed on the surface of MXenes, only Ti₂C(OH)₂ shows stable adsorption and charge transfer. An ultra‐low recovery time, the time between adsorption and desorption of a phosgene gas molecule, is achieved for both pristine and defective Ti₂C(OH)₂ with Ti vacancy. The results elucidate that a Ti₂C(OH)₂ based sensor has a high potential for efficient reversible phosgene detection.

中文翻译：

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Ti2CT2（T = F-，O-，OH-）MXene的光气检测

与表面端子试制2D碳化钛MXenes的光气气体传感特性（TI ₂ CT ₂：T = F ^-，O- ^-，OH ^{- ）}通过第一原理计算的影响。研究了在合成MXene时经常产生的Ti和C空位缺陷对结构，机械，电子和气体吸附性能的影响，以分析Ti ₂ CT ₂ MXene的光气气敏性能。原始和有缺陷的Ti ₂ C，Ti ₂ CF ₂和Ti ₂ C（OH）₂表现出金属性，使其成为气体感应的理想选择。Ti ₂ CO ₂，Ti ₂ CF ₂和Ti ₂ C（OH）_2中的Ti（C）空位缺陷导致功函数增加（减少），从而导致MXene表面与气体分子之间的相互作用增强。当光气气体分子暴露在MXenes的表面上时，只有Ti ₂ C（OH）₂表现出稳定的吸附和电荷转移。原始和有缺陷的Ti ₂ C（OH）₂以及Ti的空位都实现了超低的恢复时间，即光气气体分子吸附和解吸之间的时间。结果阐明了Ti ₂基于C（OH）₂的传感器具有用于高效可逆光气检测的高潜力。