Flexible resistive NO2 gas sensor of three-dimensional crumpled MXene Ti3C2Tx/ZnO spheres for room temperature application

• Published in: Sensors and actuators. B, Chemical Vol. 326; p. 128828
• Main Authors: Yang, Zijie, Jiang, Li, Wang, Jing, Liu, Fangmeng, He, Junming, Liu, Ao, Lv, Siyuan, You, Rui, Yan, Xu, Sun, Peng, Wang, Chenguang, Duan, Yu, Lu, Geyu
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01-01-2021; Elsevier Science Ltd
• Subjects: Flexible; Gas sensor; Gas sensors; Heterojunctions; MXene; MXenes; Nitrogen dioxide; P-n junctions; Properties (attributes); Room temperature; Selectivity; Specific surface; Spray pyrolysis; Surface area; Three-dimensional crumpled sphere structure; Zinc oxide; Gas sensor; Flexible; Three-dimensional crumpled sphere structure; Room temperature; MXene
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2020.128828

•A new three-dimensional crumpled MXene sphere and crumpled Ti3C2Tx/ZnO sphere prepared by ultrasonic spray pyrolysis method.•The preparation method reduces the loss of the advantages of high specific surface area due to stacking and aggregation.•The flexible sensor displayed high sensitivity, rapid response, good reproducibility, selectivity and stability to NO2.•The edges and defects of crumpled sphere and the formed p-n junction contribute to the most excellent NO2 sensing properties.
MXene is a potential candidate of the sensing electrode for flexible gas sensing devices and has attracted considerable attention. However, two-dimensional (2D) MXene Ti3C2Tx nanosheet is liable to stack together and lose the high specific surface area, which limits its gas sensing performance. In this work, a room-temperature flexible NO2 sensor based on three-dimensional (3D) crumpled MXene sphere prepared by ultrasonic spray pyrolysis technology is developed. Then, the properties are further improved by designing 3D crumpled MXene sphere/ZnO composites sensitive electrode with high specific surface area and active sites. The selectivity of the flexible sensing device to NO2 is further highlighted, and the response signal to 100 ppm NO2 improves from 27.27 %–41.93 %, and the recovery characteristic substantially increases from ∼30 % to ∼100 %. The excellent NO2 sensing properties of 3D crumpled MXene sphere/ZnO are attributed to the high surface area, abundance of edges and defects caused by folding, and the formation of MXene/ZnO p–n heterojunction. This work has introduced an idea to improve MXene gas-sensing properties and helped us to further understand the sensing process between MXene and target gas.