MXene/WS2 hybrids for visible-light-activated NO2 sensing at room temperature.

Optoelectronic gas sensors based on two-dimensional (2D) materials are touted as potential candidates for NO2 sensing at room temperature. However, most of the developed optoelectronic sensors to date are confined to the ultraviolet region with unsatisfactory performance. Herein, a room-temperature visible-light-activated optoelectronic NO2 sensor based on 2D/2D T3C2Tx/WS2 nanocomposites is presented. The T3C2Tx/WS2-based gas sensor exhibited fast response/recovery rate, full reversibility, long stability, good selectivity, and low detection limit (10 ppb). In addition to the efficient interfacial charge separation provided by 2D/2D heterostructures, the improvement of optoelectronic NO2 sensing performance was attributed to the visible-light-activation effects. This study provides a promising method to fabricate room-temperature high-performance gas sensors based on 2D nanomaterials.