Vanadium Disulfide Nanosheets Synthesized by Facile Liquid‐Phase Exfoliation for Ammonia Detection with High Selectivity

Abstract

Vanadium disulfide (VS2), a typical layered transition‐metal dichalcogenide, has drawn extensive attention in energy storage devices, catalysts as well as sensors due to its intriguing electronic peculiarities, whereas its chemiresistive gas sensing properties have seldom been investigated. In this contribution, first the ammonia sensing properties of VS2 nanosheets (NSs)‐based chemiresistive gas sensor are reported. VS2 NSs are synthesized through facile liquid‐phase exfoliation, and their crystal structure, micromorphology, and elemental component are characterized. Density functional theory calculation has revealed that VS2 (100) is highly affinitive to ammonia molecule, and sufficient electron transfers from ammonia to VS2, which implies VS2 NSs possess high potential for ammonia sensing. The computational results are verified by gas sensing measurement that the resistance of VS2 NSs remarkably increases upon injecting ammonia gas at low working temperature of 40 °C. Additionally, the VS2 NSs exhibit superb selectivity to ammonia. The probable mechanism for ammonia sensing can be that ammonia molecule absorbed at edge sites of VS2 NSs transfers electron to p‐type VS2 NSs, reduces hole concentration in the NSs, and thus leads to resistance enhancement of VS2 NSs.

Perspective of Vanadium Disulfide: A Rising Star Finds Plenty of Room in Single and Multielectron Energy Storage

“…It can be used for highly selective ammonia detection (Figure 4e,g). 61 Nevertheless, it is still a challenge to find a simple and high-yield stripping method to prepare single-or few-layer VS 2 nanosheets with excellent structural advantages.…”

“…(b–e) Transmission electron microscopy images of VS 2 prepared by the hydrothermal method, the solvothermal method, CVD, and a stripping method. Reproduced with permission from refs (copyright 2021 Elsevier), (copyright 2020 Elsevier), (copyright 2017 American Chemical Society), and (copyright 2022 John Wiley and Sons). (f) Schematic illustration of the CVD synthesis process.…”

“…(g) Schematic illustration of the liquid-phase stripping process of VS 2 NSs. Reproduced with permission from ref . Copyright 2022 John Wiley and Sons.…”

“…Under the protection of an argon atmosphere, the probe was sonicated in acetone solution by liquid-phase exfoliation and then sonicated in an ice bath for 12 h to obtain VS 2 nanosheets with a uniform size of 200 nm. It can be used for highly selective ammonia detection (Figure e,g) . Nevertheless, it is still a challenge to find a simple and high-yield stripping method to prepare single- or few-layer VS 2 nanosheets with excellent structural advantages.…”

Advances in two‐dimensional engineered nanomaterials applications for the agro‑ and food‐industries

“…62 Another example of 2D nanostructures is the report on germanium selenide, which has been theoretically studied for its use as a gas sensor, including ammonia, carbon monoxide, and oxygen, which are gases of interest in agriculture-and food-related applications. 63 Furthermore, the exceptional optical properties of TMDs and MXenes are fueling the development of optodetectors of harmful organisms, toxins, or other molecules of interest, 64,65 which are especially promising due to their high speed and sensitivity, two parameters that are key factors for new sensor technology development.…”