A Study Based on the First-Principle Study of the Adsorption and Sensing Properties of Mo-Doped WSe2 for N2O, CO2, and CH4

Abstract

As industry continues to develop rapidly, the greenhouse effect is becoming increasingly severe. CO2, CH4, and N2O are the three primary greenhouse gases, making their effective monitoring a crucial step in reducing emissions. This paper investigates the gas sensing performance of Mo-doped WSe2 for these three gases, through a theoretical study. First, using first-principles calculations, the doping behavior of Mo in WSe2 is examined. Subsequently, the adsorption properties of Mo-WSe2 for CO2, CH4, and N2O are analyzed by calculating adsorption energy, charge transfer, the electron localization function (ELF), Hirshfeld partition (IGMH), and the density of states (DOSs), culminating in an analysis of its sensing properties. The results indicate that when Mo is positioned above the upper Se atom, the structure is most stable. Therefore, this position is selected as the optimal adsorption site for studying the adsorption of the three gases. The adsorption energies for CO2, CH4, and N2O are 1.349 eV, −1.194 eV, and −0.528 eV, respectively, with corresponding charge transfers of 0.418, 0.450, and 0.115. In the N2O and CO2 adsorption systems, significant adsorption energy and charge transfer are observed, leading to relatively better adsorption compared to the CH4 system. Additionally, considering the adsorption performance, Mo-WSe2 demonstrates good sensor response and desorption times for N2O and CO2 at temperatures above 298 K. The findings of this research provide theoretical guidance for the application of Mo-WSe2 as a gas sensing material for detecting greenhouse gases.