Abstract

Based on the first principles of density functional theory, the adsorption behavior of H2CO on original monolayer MoS2 and Zn doped monolayer MoS2 was studied. The results show that the adsorption of H2CO on the original monolayer MoS2 is very weak, and the electronic structure of the substrate changes little after adsorption. A new kind of surface single cluster catalyst was formed after Zn doped monolayer MoS2, where the ZnMo3 small clusters made the surface have high selectivity. The adsorption behavior of H2CO on Zn doped monolayer MoS2 can be divided into two situations. When the H-end of H2CO molecule in the adsorption structure is downward, the adsorption energy is only 0.11 and 0.15 eV and the electronic structure of adsorbed substrate changes smaller. When the O-end of H2CO molecule is downward, the interaction between H2CO and the doped MoS2 is strong leading to the chemical adsorption with the adsorption energy of 0.80 and 0.98 eV. For the O-end-down structure, the adsorption obviously introduces new impurity states into the band gap or results in the redistribution of the original impurity states. All of these may lead to the change of the chemical properties of the doped MoS2 monolayer, which can be used to detect the adsorbed H2CO molecules. The results show that the introduction of appropriate dopant may be a feasible method to improve the performance of MoS2 gas sensor.

Highlights

  • In recent years, two-dimensional (2D) materials have attracted much attention due to their unique physical, chemical and electrical properties (Abbasi and Sardroodi, 2018a; Abbasi and Sardroodi, 2018b; Wu et al, 2018; Abbasi, 2019; Abbasi and Sardroodi, 2019)

  • The results show that, compared with undoped MoS2, doping Zn atoms in the defective monolayer MoS2 is beneficial to the adsorption of H2CO

  • According to the first principles calculations, we have studied the effects of Zn doping S vacancy on the electronic structure, magnetic properties and chemical activity of monolayer MoS2

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Summary

Introduction

Two-dimensional (2D) materials have attracted much attention due to their unique physical, chemical and electrical properties (Abbasi and Sardroodi, 2018a; Abbasi and Sardroodi, 2018b; Wu et al, 2018; Abbasi, 2019; Abbasi and Sardroodi, 2019). MoS2 has large specific surface area, surface activity and excellent adsorption capacity, so it is a special gas storage material or gas sensing material source (Zhang et al, 2017; Zhang et al, 2018; Zhou et al, 2018; Chen et al, 2019; Kathiravan et al, 2019; Tan et al, 2020). These excellent properties make the monolayer MoS2 have potential applications in the field of gas sensing

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