Ti₃C₂T_<i>x</i> Nanosheet/Bi₂S₃ Nanobelt Composites\nfor NO₂ Gas Sensing

Abstract

Along\nwith the revolution of the Internet of Things (IoT), smart,\nflexible, easily fabricated, and highly sensitive gas sensors are\nessential for many portable electronics. In this study, a wearable\nNO₂ sensor based on a nanomesh structure woven with Ti₃C₂T_<i>x</i> microflakes and\nBi₂S₃ nanobelts operated at room temperature\nwas successfully designed and prepared. The effects of the mass ratio\nbetween two materials on the performance were evaluated. Bi₂S₃ nanobelts embedded inside accordion-like Ti₃C₂T_<i>x</i> provide large specific\nsurface areas and abundant active sites for the adsorption of NO₂ molecules. Attributed to the high conductivity of Ti₃C₂T_<i>x</i>, the carriers\ngenerated in the sensitive layers are easily transmitted during sensing,\nthus significantly reducing the response and recovery times. The sensor\nbased on the nanomesh containing 30 wt % Ti₃C₂T_<i>x</i> exhibits excellent sensing performance,\nfast response/recovery rates, and high stability even in arbitrary\ndeformed shape conditions. Upon exposure to 1 ppm NO₂,\nthe response of the sensor is 12.67, and the response/recovery times\nare 5/28 s, respectively. A stable sensing performance can be maintained\nafter 1500 cycles of deformation. This work demonstrates a simple\nbut reliable manufacturing strategy of wearable gas sensors for the\nnext generation of IoT monitoring network-linking human activities.