First-Principles Study on Adsorption of CO2 and SO3 in Flue Gas by Sc Doped MoS2 Sensor

Abstract

Based on the first-principles method of density Functional Theory (DFT), a scandium atom doped twodimensional MoS2 model was constructed in this paper. The adsorption behavior of CO2 and SO3 on the surface of intrinsic MoS2 and Sc–MoS2 were studied, and the adsorption structure and electronic properties of the adsorption system were calculated. The results show that the geometric structure of the adsorption of CO2 and SO3 by intrinsic MoS2 changed a little, the adsorption energy is −0.756 eV and −0.910 eV, respectively. The band gap width does not change significantly. After Sc doped in MoS2, the binding energy of Sc–MoS2 is −1.115 eV, the band gap width changes from 1.720 eV to 0.323 eV, which reduced significantly. At the same time, combined with the electron fractal wave state density diagram, it is found that the electrons at Fermi level are mainly provided by Sc, which indicated that doping contributes to improve the system conductivity. After the adsorption of CO2 and SO3 by Sc–MoS2, the geometric structure of the former changed a little, the adsorption energy is −0.383 eV, and the forbidden band width changes little. The geometric structure of the latter changes significantly, the Sc–S bond length is elongated, SO3 changes from a plane equilateral triangle to a pyramid shape, the adsorption energy is −4.823 eV, the forbidden band width becomes negative, the conductivity of the system is significantly improved, but it is difficult to decompose.