First Principles Study of Gas Molecules Adsorption on Monolayered β-SnSe

Tianhan Liu,Hongbo Qin,Daoguo Yang,Guoqi Zhang

doi:10.3390/coatings9060390

Abstract

For the purpose of exploring the application of two-dimensional (2D) material in the field of gas sensors, the adsorption properties of gas molecules, CO, CO2, CH2O, O2, NO2, and SO2 on the surface of monolayered tin selenium in β phase (β-SnSe) has been researched by first principles calculation based on density functional theory (DFT). The results indicate that β-SnSe sheet presents weak physisorption for CO and CO2 molecules with small adsorption energy and charge transfers, which show that a β-SnSe sheet is not suitable for sensing CO and CO2. The adsorption behavior of CH2O molecules adsorbed on a β-SnSe monolayer is stronger than that of CO and CO2, revealing that the β-SnSe layer can be applied to detect CH2O as physical sensor. Additionally, O2, NO2, and SO2 are chemically adsorbed on a β-SnSe monolayer with moderate adsorption energy and considerable charge transfers. All related calculations reveal that β-SnSe has a potential application in detecting and catalyzing O2, NO2, and SO2 molecules.

Highlights

The detection of gases, especially the toxic gases, has aroused tremendous interest for its extensive application in the fields of agricultural production, industrial control, medical diagnosis, and environmental detection [1]
It has been verified that the basic set superposition error (BSSE) effect is not considered when the numerical basis sets are applied in DMOL3 [31,32,33]
The Ea values of the CO, CO2, and CH2 O gas molecules adsorbed on the β-SnSe monolayer are −0.202, −0.175, and −0.322 eV, respectively

Summary

Introduction

The detection of gases, especially the toxic gases, has aroused tremendous interest for its extensive application in the fields of agricultural production, industrial control, medical diagnosis, and environmental detection [1]. The traditional gas sensors, transition metal oxides sensors, have the shortcoming of a high operating temperature (200–600 ◦ C) [2,3] and low sensing response [4], which have motivated researchers to search for appropriate materials as reliable and high performance gas sensors [5]. Because 2D materials exhibit excellent physicochemical properties, such as the high ratio of surface area to volume [6], ultrahigh carrier mobility [7], excellent mechanical performance [8], and low electrical noise [9,10], it is possible for them to sense gas molecules at room temperature and normal pressure [11,12]. It is noteworthy that some stable layered materials show semiconductor characteristics with an appropriate band gap, which is of vital importance for the sensing performance [18,19]

Methods

Results

Conclusion