Borophene-PbS heterostructures for NO2 detection at room temperature

Developing room-temperature gas sensors with ultrahigh sensitivity and rapid response to nitrogen dioxide (NO 2 ), a hazardous air pollutant, remains critically important yet challenging. Borophene, a two-dimensional (2D) elemental nanomaterial, exhibits promising sensing potential owing to its exceptional electronic conductivity and abundant active surface sites. However, pristine borophene suffers from limited response kinetics and diminished sensitivity at elevated NO 2 concentrations. Herein, we introduce a novel heterostructure composed of lead sulfide (PbS) nanoparticles decorated on α'-4H-borophene nanosheets, synthesized through a facile ultrasound-assisted assembly strategy. The resultant borophene-PbS composite demonstrates outstanding sensing performance, exhibiting a remarkable sensitivity of 1692 % at 75 ppm NO 2 , an ultrafast response (<10 s), and an exceptionally low detection limit of 20 ppb at ambient conditions. Comprehensive structural and mechanistic analyses reveal that synergistic interfacial coupling between borophene and PbS significantly enhances NO 2 adsorption and accelerates interfacial charge transfer dynamics. This work not only overcomes intrinsic limitations of pristine borophene but also establishes a scalable approach toward next-generation 2D-based gas sensors with superior sensitivity, selectivity and stability.