MoS_(2)/SnS_(2)异质结催化性能增强的第一性原理研究

The first principle study on the catalytic enhancement of MoS_(2)/SnS_(2) heterojunction

基于密度泛函理论的第一性原理计算方法,系统研究了单层MoS_(2)、单层SnS_(2)和MoS_(2)/SnS_(2)异质结体系的几何结构、电子结构和功函数等性能.结果表明,MoS_(2)/SnS_(2)异质结的带隙明显小于单层MoS_(2)(001)和单层SnS_(2)(001),这有利于降低光子激发能,提高光吸收能力.通过计算MoS_(2)/SnS_(2)异质结的差分电荷密度,发现电荷的重新分布主要发生在MoS_(2)的界面附近,SnS_(2)内部的电荷密度变化很小,这表明构建的异质结可以有效改善复合体系的电荷转移能力,抑制光生电子和空穴的复合,从而提高材料的催化性能.

Based on the first-principle calculation method of density functional theory,the geometric structure,electronic structure and work function of monolayer MoS_(2),monolayer SnS_(2)and MoS_(2)/SnS_(2)heterojunction systems were systematically studied.The results indicate that the band gap of MoS_(2)/SnS_(2)heterojunction is significantly smaller than that of pure MoS_(2)(001)and pure SnS_(2)(001),which is conducive to reducing photon excitation energy and improving light absorption capacity.Through the calculation of MoS_(2)/SnS_(2)heterojunction charge density difference,it is found that the redistribution of charge mainly occurred near the interface of MoS_(2),SnS_(2)charge density of the internal change is very small.This indicates that the heterojunction can effectively improve the charge transfer ability of the composite system,inhibit the photoelectron and hole recombination,and thus improve the catalytic performance of the material.