Research Studies
Study Tracker
Adsorbtive removal of HF toxic gas via tinsulfide monolayer modification: A molecular perspective.
| Chemosphere | Arabieh M, Basaadat MR. | 143231.
HF Other

Abstract

Highlights

  • DFT calculations confirm HF molecule is physisorbed on SnS monolayer.
  • HF is chemically adsorbed on monovacancy SnS surface.
  • Fluorinated tinsulfide (F2SnS) is a promising candidate for adsorptive removal of HF.

Hydrofluoric Acid (HF) is considered one of the most hazardous chemicals used in industrial plants. Even small exposures to HF can have fatal consequences if not promptly and properly treated. Various research teams have presented numerous substances with the objective of capturing or detecting toxic HF gas. In this study, we explore the impact of HF gas on a single layer of SnS by employing density functional theory (DFT). The interaction nature between the gas molecule and the adsorbent is elucidated by analyzing the related adsorption energy, electronic structure properties and differential charge transfer. The findings indicate that HF is physically adsorbed on the pristine SnS with an adsorption energy value of -0.63 eV. By introducing a Sn mono vacancy defect, the modification of SnS enhances the adsorption energy to -1.26 eV, resulting in a chemisorption process. Molecular fluorine (F2) was discovered to undergo a barrierless reaction with SnS, resulting in the formation of fluorine-substituted SnS. It has been discovered that the substitution of fluorine atoms enhances the reactivity of SnS towards hydro- gen fluoride gas. The adsorption potential of the studied structures towards HF gas was determined to be in the following order: F2SnS > VSn-SnS > VS-SnS ? SnS. The current study is anticipated to offer new molecular insights that could lead to the creation of innovative devices for detecting or eliminating HF toxic gas from a specific atmosphere.

EXCERPTS:

Introduction

Hydrogen fluoride (HF) is a colorless, toxic and corrosive gas causing intense of eye, nose, and throat irritation [1]. Anthropogenic and natural sources are two main releasing sources of HF into the atmosphere. The former is related to the industrial manufacturing plants and later is due to volcanic eruptions and marine aerosols [2]. Different theoretical and experimental research groups have introduced several potent materials for the aim of capturing or sensing HF toxic gas. Particularly, theoretical studies based on molecular modeling approaches have been extensively conducted in this area, which led to the proposal of new materials applicable in the detection or adsorption of HF gas.

A brief survey in the literature reveals that various bulk materials including TiO2, Al2O3, AlF3, YF3, HoF3, MgF2, Mg12O11-X (X:S, P, N, B), LiMn2O4 and so on have been theoretically evaluated for HF capturing or detection applications [3], [4], [5], [6], [7], [8], [9], [10]. Moreover, selected 2D structures such as PdAs2, borophene, ZnS monolayer, Pt-decorated graphene, CNT, AlN nanotube, etc. have been studied for the aim of HF adsorption [11], [12], [13], [14], [15], [16], [17], [18]. The supplementary file’s Table-S1 presents previously reported adsorption energies of HF on both bulk and two-dimensional (2D) materials. An examination of the data in Table-S1 indicates that the adsorption energy of HF on bulk materials is significantly greater than that observed for 2D materials. However, it is crucial to recognize that the surface-to-volume ratio in 2D materials is considerably higher, which positions them as more advantageous candidates for applications in gas adsorption and detection technologies.

Recently, tin (II) sulfide monolayer (SnS) has been the subject of several theoretical and experimental studies in the field of gas adsorption. This 2D material not only has been experimentally synthesized but also has been shown to have superior properties such as high electron mobility, and high adsorption coefficient [19], [20], [21], [22], [23], [24], [25], [26]. In the context of devices, maintaining a high level of stability is crucial for ensuring a prolonged lifespan. Extensive research has shown that two-dimensional SnS exhibits exceptional stability when exposed to harsh conditions such as acids and electrolytes, making it an ideal material for long-term cycling stability [27]. This feature enhances its usefulness in comparison to other similarly structured such as black phosphorus and germanium (II) sulfide, which necessitate anhydrous or anaerobic environments [28]. Various reports suggested SnS monolayer for adsorption or sensing of gas molecules. Shukla et al. showed that O3 and SO3 are chemisorbed over SnS while CH2O, H2S, and HCN are physiosorbed [29]. Using density functional theory calculations, Hu and coworkers, predicted that monolayer SnS could be an outstanding candidate for NO2 sensing devices [30]. The other reports suggested that imposing mono vacancy defect and single atom doping may change pristine SnS to a prominent material for gas adsorption [31], [32], [33], [34], [35], [36].

The main goal of the current study is to examine the adsorption potential of pristine and modified SnS monolayer toward toxic HF gas. To achieve this goal, the adsorption of molecular HF on pristine, fluorinated, and defected SnS has been systematically investigated based on density function theory calculations. Various indexes including adsorption energy, density of state (DOS), partial density of state (PDOS), differential charge transfer (DCT) and band structures curves have been employed to evaluate the adsorption nature of HF on SnS monolayer. It was discovered that Sn point defects and fluorine substitution could improve the interaction between HF and SnS, resulting in an increase in estimated adsorption energy. The current study’s findings are likely to provide light on new features for the design of unique HF capturing/sensing devices.

Original abstract online at https://www.sciencedirect.com/science/article/abs/pii/S0045653524021295?via%3Dihub