摘要
无机非金属氮化碳材料由于电子结构独特、不含金属、化学性质稳定且具有一定的可见光响应等,在能源和材料领域的地位日益突出,具有越来越广阔的研究和应用前景。基于氮化碳材料的二维层状结构和性质特征及其相关应用,本文采用密度泛函理论超软赝势方法,对氮化碳前驱体(melon)、氮氢缺陷前驱体以及石墨相氮化碳(g-C3N4)晶体及其表面结构、能带以及功函数等进行了研究,分析了二维氮化碳材料的物化性质与微观结构的关系。结果表明:Melon为直接带隙半导体,随着结构中氢键的减少,不同层状结构表面的价带和导带边缘位置均会发生改变,从直接带隙变为间接带隙又变回直接带隙半导体,说明可以通过材料表面结构设计达到调控其带隙和光学性质实现不同应用的目的。另外,研究发现不同二维氮化碳材料的费米能级随表面氢键的减少而上移,导致功函数随之减小,表面反应活性增强。本研究结果对促进二维氮化碳材料的广泛应用提供了前提和理论基础,同时也为二维材料结构设计提供了新思路和应用示范。
Inorganic metal-free carbon nitride(CN)materials are becoming more and more important in the field of energy and materials,and have more and more extensive research and application prospects due to their unique electronic structure,metal-free,stability and visible light response.Based on the two-dimensional CN layered structure,physicochemical properties and their different application fields,the carbon precursor(Melon),the nitrogen hydrogen defect precursor and the graphite phase carbon nitride(g-C3 N4)crystal and its surface structure,band structure and work function are systematically calculated and analyzed by the planewave ultrasoft pseudopotential method based on the density functional theory.It is found that Melon is a direct bandgap semiconductor,with the reduction of hydrogen bonds in the structure,the edge position of the valence band and the conduction band on the surface of different layered structures will move to the higher energy,the bandgap will become from direct to indirect and back to direct.It is shown that it is possible to control the bandgap and optical properties of materials and achieve different applications through surface structure design.Furthermore,it is also found that the Fermi level of different CN materials will increases with the decrease of hydrogen bonds on the surface,resulting in the decrease of the work function and the enhancement of surface reactivity.The control mechanism combining the macroscopic catalytic activity and the microscopic structures,obtained in this work,can provide a theoretical reference and basis for the extensive application of two dimensional CN materials,and also provide new ideas and demonstration for the design of two-dimensional material structure.
作者
韩清珍
温浩
Han Qingzhen;Wen Hao(State Key Laboratory of Multiphase Complex Systems,Research Department for Environmental Technology and Engineering,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China)
出处
《科研信息化技术与应用》
2018年第4期45-54,共10页
E-science Technology & Application
基金
国家自然科学基金资助项目(11504374
11274040)
"十三五"院信息化专项化学学科领域重点数据库建设与应用服务(XXH1350303-103)
关键词
二维氮化碳材料
结构设计
直接带隙
间接带隙
构效关系
Two dimensional CN materials
structure design
direct bandgap
indirect bandgap
structure–properties relationship
