Plasmonic Au-enabled photoenhanced room temperature NO2 sensing of 2D SnS2-heterostructure via single-step mechanochemical synthesis

Abstract

The development of high-performance gas sensors for NO 2 detection is critical due to its harmful effects on human health and environment. Tin disulfide (SnS 2 ), with its layered structure akin to transition metal dichalcogenides (TMDs), shows potential for NO 2 sensing. However, SnS 2 -based sensors typically exhibit weak response and incomplete recovery at room temperature. In this study, we propose 2D SnS 2 nanosheets modified with gold nanoparticles (Au-NPs) by a single-step mechanochemical synthesis, in which photoelectric sensors depend on the light absorption properties of the sensitive material, thus Au-NPs with LSPR effect coupled with SnS 2 can enhance the absorption capacity of the composite in the UV light band. The higher light absorption efficiency means that more electrons and holes can be produced under light excitation, and the holes can react with the NO 2 adsorbed on the surface of the material, speeding up the desorption of NO 2 . As compared to the unmodified SnS 2 sensor, the response values of Au/SnS 2 sensor to 10 ppm NO 2 at room temperature increased from 7.74 to 16.01, while the response/recovery time reduced from 169/201 s to 98/154 s. Moreover, the Au/SnS 2 sensor can detect low concentrations of NO 2 (50 ppb) with excellent repeatability, selectivity, and long-term stability at room temperature. This study demonstrates that integrating Au-NPs modification with UV photo-assistance is a viable strategy for developing high-performance room temperature gas sensors. • 2D SnS 2 nanosheets modified with gold nanoparticles by a single-step mechanochemical synthesis. • Thanks to the electron sensitization, chemical sensitization, as well as LSPR effect introduced by Au-NPs, the Au/SnS 2 sensor shows high response to 10 ppm NO 2 even at room temperature. • The sensor exhibits highly selective to NO 2 and excellent long-term stability.