g-C3N4表面结构的第一性原理研究  

First-principle study on the properties of g-C_3N_4 surface structure

作　　者：苏巧智 韩清珍[2] 高锦花[1,2] 温浩[2] 江兆潭[1] 

机构地区：[1]北京理工大学物理学院,北京100081 [2]中国科学院过程工程研究所,多相复杂系统国家重点实验室,北京100190

出　　处：《计算机与应用化学》2017年第4期269-274,共6页Computers and Applied Chemistry

基　　金：国家自然科学基金资助项目(11274040,11504374);中国科学院介尺度研究中心创新基金资助项目(COM2015A001)

摘　　要：石墨相氮化碳(g-C_3N_4)由于不含金属组分、化学性质稳定、且具有可见光响应,在光催化领域具有越来越广阔的应用前景。本文基于密度泛函理论的平面波超软赝势方法,对不同原子层数的g-C_3N_4的表面能、电子结构和光学性质等进行了研究。结果表明:g-C_3N_4的表面能随着原子层数的增加而逐渐降低,从6层原子开始表面能小于0,说明当原子层数大于6时,g-C_3N_4形成稳定的层状表面结构;不同层数的g-C_3N_4表面结构均为间接带隙半导体,导带底主要由C的2p态和N的2p态杂化而成,价带顶主要由N的2p态和N的2s态构成。本文研究结果为层状结构的g-C_3N_4催化材料的设计、制备和催化性能研究提供了理论依据和数据基础。Graphitic carbon nitride （g-C3N4） has a wider and wider application prospect in the field of photocatalysis, for it is metal-free and chemically inert, and has some response to visible-light. In this work, based on the planewave ultrasoft pseudopotential method of the density functional theory, the surface energy, band structure, and density of states of g-C3N4 surface structure for different atomic layers of 3, 4, 5, 6, 7 were systematically investigated. Three main results were obtained： i） The surface energy of g-C3N4 surface structure was decreasing with the increase in atomic layer. The surface energy was less than 0 starting from 6-layer, which mains these g-C3N4 surface structures were stable; ii） All the g-CaN4 surface structures for different atomic layers belong to indirect gap semiconductor, which were the same as g-C3N4 crystal structure, iii） For all of the g-C3N4 surface structures of different atomic layers, their conduction band minimums are mainly composed of C 2p states and N 2p states, while their valence band maximums mainly consists ofN 2p states and N 2s states. Especially, the N atoms were found to be the active sites in g-C3N4. This research will be viewed as the useful theoretical reference and data basis for designing and preparing g-C3N4 photocatalyst and its photocatalytic property modification.

关 键 词：g-C3N4 原子层数 表面能 电子结构 光学性质 

分 类 号：O64[理学—物理化学] TQ59[理学—化学]