Ti₃C₂T_x Nanosheet/Bi₂S₃ Nanobelt Composites for NO₂ Gas Sensing

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.