Exploration of the Transition Metal-Doped CrS<sub>2</sub> Monolayer as a Gas Sensor of Toxic Gases Based on the Density Functional Theory Method
Ying Duan, Yang Xu, Zengming Qin, Ye Tian, Yuyang Wang, Jing Wang
Abstract
In order to detect the harmful gases produced in the nonferrous metal smelting process, this study uses the transition metal atom (Fe, Co, Ni, and Cu)-doped CrS 2 (TM/CrS 2 ) monolayer as a sensing material to achieve high-sensitivity detection of CO, HCHO, NO, NO 2, and SO 2 gases. Density functional theory (DFT) calculations indicate that the TM/CrS 2 structure exhibits relative stability; the values of E bind for the dopants on the CrS 2 substrate are noted as −4.565 eV for Fe/CrS 2, −4.187 eV for Co/CrS 2, −5.286 eV for Ni/CrS 2, and −3.695 eV for Cu/CrS 2 . Additionally, the adsorption energies of all adsorption systems are less than −0.800 eV (except for SO 2 -Cu/CrS 2 ), indicating chemical adsorption. Analysis of the band structure and density of states indicates that the electronic properties of the doped and adsorbed systems have undergone significant changes. Ni/CrS 2 and Co/CrS 2 exhibit high sensitivity (>10 2 ) toward the five target gases (except for HCHO-Co/CrS 2 ), thus making them suitable as resistive-type sensors. The work function variations of the Fe/CrS 2 adsorption system exceed 5%, which can be used as a WF-based sensor. All of the above gases can be separated from TM/CrS 2 via temperature control. The results of this study demonstrate the gas-sensing potential of TM/CrS 2 monolayer materials.