Edge‐Enriched Mo<sub>2</sub>TiC<sub>2</sub>T<sub>x</sub>/MoS<sub>2</sub> Heterostructure with Coupling Interface for Selective NO<sub>2</sub> Monitoring
Qiuni Zhao, Wenzhe Zhou, Mingxiang Zhang, Yang Wang, Zaihua Duan, Chaoliang Tan, Bohao Liu, Fangping Ouyang, Zhen Yuan, Huiling Tai, Yadong Jiang
Abstract
Abstract Endowed with rich terminal groups, good electrical conductivity, and controllable structure, transition metal carbides/nitrides (MXenes) have attracted extensive attention for potential application in gas sensor, but long‐standing challenges of the MXenes (titanium carbide as the representative) are their limited selectivity and sensitivity. Herein, a high‐active double transition‐metal titanium molybdenum carbide (Mo 2 TiC 2 T x ) with superstrong surface adsorption (−3.12 eV) for NO 2 gas molecule is proposed, and it is further coupled with molybdenum disulfide (MoS 2 ) by interface modulation to construct an edge‐enriched heterostructure. Due to the synergistic effect of strong adsorption, rich adsorption sites, and coupling interface of Mo 2 TiC 2 T x /MoS 2 composite, the as‐fabricated Mo 2 TiC 2 T x /MoS 2 gas sensor exhibits an outstanding response toward NO 2 with high selectivity against various interference gases, which is well supported by density functional theory calculations. Meanwhile, the sensor exhibits a sensitivity of 7.36% ppm −1 , detection limit of 2.5 ppb, and reversibility at room temperature. A portable, wireless NO 2 monitoring system is demonstrated for gas leakage searching and dangerous warning based on Mo 2 TiC 2 T x /MoS 2 gas sensor. This work facilitates the gas sensing application of MXenes, and provides an avenue for the development of wireless sensing system in environmental monitoring and safety assurance.