First-Principles Study of Ti-Deficient Ti 3 C 2 MXene Nanosheets as NH 3 Gas Sensors

作者：Li Li, Li Li, Honghao Cao, Zhishen Liang, Yongfa Cheng, Tingting Yin, Zunyu Liu, Shuwen Yan, Shuangfeng Jia, Luying Li, Luying Li, Jianbo Wang, Yihua Gao · 发表于：ACS Applied Nano Materials · 年份：2022 · DOI：10.1021/acsanm.1c04158 · 被引用次数：68 · 研究领域：MXene and MAX Phase Materials、2D Materials and Applications、Graphene research and applications

Sensitive gas sensors are becoming increasingly important in toxic gas detection and environmental monitoring. The applications of conventional gas sensors are limited due to their low sensitivity or high operating temperature. MXenes with high conductivity are conducive to the rapid transmission of electrons and are suitable as highly sensitive NH 3 gas sensors. Considering the limited research on the experimental details and sensing mechanism of MXene-based NH 3 gas sensors, our research focuses on precisely controlling the atomic structure of MXenes to improve the performance of NH 3 gas sensors. The atomic structures of a typical monolayer Ti 3 C 2 O 2 MXene and its Ti-deficient counterpart as the NH 3 gas sensor are systematically studied through first-principles calculations and the nonequilibrium Green’s function method. The Ti-deficient Ti 3 C 2 O 2 MXene has a relatively stronger physical interaction with NH 3 and is comparatively more suitable as a highly sensitive NH 3 gas sensor. Atomic-level device simulations show that the current has a greater change when NH 3 is adsorbed on the surface of Ti-deficient Ti 3 C 2 O 2 . These detailed calculations provide substantial theoretical support and a useful design scheme to improve the sensitivity of MXene-based gas sensors by deliberately introducing Ti vacancies in the MXene.