Two-Dimensional Nanomaterials for Gas Sensing Applications: The Role of Theoretical Calculations

Abstract

Two-dimensional (2D) nanomaterials have attracted a large amount of attention regarding gas sensing applications, because of their high surface-to-volume ratio and unique chemical or physical gas adsorption capabilities. As an important research method, theoretical calculations have been massively applied in predicting the potentially excellent gas sensing properties of these 2D nanomaterials. In this review, we discuss the contributions of theoretical calculations in the study of the gas sensing properties of 2D nanomaterials. Firstly, we elaborate on the gas sensing mechanisms of 2D layered nanomaterials, such as the traditional charge transfer mechanism, and a standard for distinguishing between physical and chemical adsorption, from the perspective of theoretical calculations. Then, we describe how to conduct a theoretical analysis to explain or predict the gas sensing properties of 2D nanomaterials. Thirdly, we discuss three important methods that have been applied in order to improve the gas sensing properties, that is, defect functionalization (vacancy, edge, grain boundary, and doping), heterojunctions, and electric fields. Among these strategies, theoretical calculations play a very important role in explaining the mechanisms underlying the enhanced gas sensing properties. Finally, we summarize both the advantages and limitations of the theoretical calculations, and present perspectives for further research on the 2D nanomaterials-based gas sensors.

First‐Principles Investigation of Antimonene Nanoribbons for Sensing Toxic NO2 Gas

“…As reported previously, the edge states are most sensitive toward the adsorption of foreign molecules, due to their increased number of dangling bonds, different local stoichiometry, and maximal asymmetry. [21,44] Thus, ribbon edges exhibit better surface properties for catalysis and gas-detecting performance. Henceforth, we have considered the adsorption of NO 2 molecule at the edges of SbNRs.…”

“…[15][16][17][18][19] 2D nanostructured materials provide vast dynamic surface area for the adsorption of the gas molecule due to the result of their novel properties and considerable surface-to-volume proportion. [20,21] These properties effectively advocate the adsorption of gases on nanostructures and eventually prompt exceptionally sensitive sensor operation.…”

Limiting the Oxidation of WS2 Nanostructures by Oleylamine Surface Passivation for Room Temperature NH3 Sensing

“…In this case, the NH3 lone pair electron is transferred to the OLA/WS2 sensor conduction band upon adsorption. Based on theoretical calculations, the analyte is physically adsorbed on the surface of a perfect 2D monolayer [38]. However, defects were introduced during colloidal synthesis of OLA/WS2 nanostructures providing more reactive sites than the perfect lattice.…”

Mo-Based Layered Nanostructures for the Electrochemical Sensing of Biomolecules

“…Among the 2D nanomaterials, graphene, the first discovered 2D carbon material coming from the exfoliation of graphite, is attracting significant interest; but its major disadvantage is the lack of bandgap, which limits its use in some applications. In contrast to graphene, several 2D inorganic nanomaterials possess a sizable band gap and high reactivity towards gaseous species, including under ambient conditions, promising interesting applications in correlated fields [ 3 ]. The two-dimensional electron confinement of ultra-thin 2D nanomaterials, also leads to very interesting electrical properties compared to other nanostructures with different morphologies.…”