Highly sensitive and recoverable room-temperature NO2 gas detection realized by 2D/0D MoS2/ZnS heterostructures with synergistic effects

Abstract

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have received emerging attention due to their rich active sites, layered structure, and suitable electronic structure for gas sensing at room temperature (25 °C). However, the sensitivity, recoverability, stability and selectivity of TMDs-based gas sensors have remained a grand challenge. Herein, a novel 2D/0D molybdenum disulfide (MoS2)/zinc sulfide (ZnS) based gas sensor was rationally designed via a two-step solution process, enabling high-performance detection of nitrogen dioxide (NO2) gas at room temperature. Specifically, the MoS2/ZnS heterostructures manifest a greatly enhanced response performance (S = 7.2) to 5 ppm NO2 in comparison with the bare MoS2 nanosheets. The gas sensor can be completely recovered after re-exposing to the air for 4.6 min at room temperature without using any external auxiliary treatments. Our optimized gas sensor not only exhibits an ultra-low theoretical limit of detection (14 ppb), but also shows an ultrahigh selectivity and outstanding stability. We further showed that the greatly enhanced gas sensing performance of 2D/0D MoS2/ZnS can be ascribed to the unique structure as well as the synergistic effects between MoS2 nanosheets and ZnS nanoparticles from the geometrical, charge transfer, equivalent resistance, and chemical aspects. This work provides a promising approach to the fabrication of high-performance gas sensing materials for environmental monitoring at room temperature.