Ti₃C₂T_x Nanosheet/Bi₂S₃ Nanobelt Composites for NO₂ Gas Sensing

Abstract

Along with the revolution of the Internet of Things (IoT), smart, flexible, easily fabricated, and highly sensitive gas sensors are essential for many portable electronics. In this study, a wearable NO 2 sensor based on a nanomesh structure woven with Ti 3 C 2 T x microflakes and Bi 2 S 3 nanobelts operated at room temperature was successfully designed and prepared. The effects of the mass ratio between two materials on the performance were evaluated. Bi 2 S 3 nanobelts embedded inside accordion-like Ti 3 C 2 T x provide large specific surface areas and abundant active sites for the adsorption of NO 2 molecules. Attributed to the high conductivity of Ti 3 C 2 T x , the carriers generated in the sensitive layers are easily transmitted during sensing, thus significantly reducing the response and recovery times. The sensor based on the nanomesh containing 30 wt % Ti 3 C 2 T x exhibits excellent sensing performance, fast response/recovery rates, and high stability even in arbitrary deformed shape conditions. Upon exposure to 1 ppm NO 2 , the response of the sensor is 12.67, and the response/recovery times are 5/28 s, respectively. A stable sensing performance can be maintained after 1500 cycles of deformation. This work demonstrates a simple but reliable manufacturing strategy of wearable gas sensors for the next generation of IoT monitoring network-linking human activities.