物理化学学报 >> 2016, Vol. 32 >> Issue (10): 2488-2494.doi: 10.3866/PKU.WHXB201606222

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碱金属修饰g-C3N4的能带结构调控与载流子迁移过程

祝林1,2,马新国1,2,*(),刘娜1,徐国旺1,2,黄楚云1,2,*()   

  1. 1 湖北工业大学理学院,武汉430068
    2 湖北工业大学太阳能高效湖北省协同创新中心,武汉430068
  • 收稿日期:2016-03-18 发布日期:2016-09-30
  • 通讯作者: 马新国,黄楚云 E-mail:maxg2013@sohu.com;chuyunh@163.com
  • 基金资助:
    国家自然科学基金(51102150,51472081);湖北工业大学高层次人才启动基金(GCRC13014);湖北省协同创新中心开放基金项目(HBSKFZD2014003,HBSKFZD2014011,HBSKFZD2015004);和湖北省协同创新中心大学生科技创新基金资助(HBSDY201511)

Band Structure Modulation and Carrier Transport Process of g-C3N4 Doped with Alkali Metals

Lin ZHU1,2,Xin-Guo MA1,2,*(),Na LIU1,Guo-Wang XU1,2,Chu-Yun HUANG1,2,*()   

  1. 1 School of Science, Hubei University of Technology, Wuhan 430068, P. R. China
    2 Hubei Collaborative Innovation Center for High-efficiency Utilization of Solar Energy, Hubei University of Technology, Wuhan 430068, P. R. China
  • Received:2016-03-18 Published:2016-09-30
  • Contact: Xin-Guo MA,Chu-Yun HUANG E-mail:maxg2013@sohu.com;chuyunh@163.com
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(51102150,51472081);Foundation of Hubei University of Technology for High-level Talents, China(GCRC13014);Development Founds of Hubei Collaborative Innovation Center, China(HBSKFZD2014003,HBSKFZD2014011,HBSKFZD2015004);and Students Research Fund of Hubei Collaborative Innovation Center, China(HBSDY201511)

摘要:

采用平面波超软赝势方法研究了Li、Na、K三种碱金属离子修饰对g-C3N4能带结构和载流子迁移过程的影响。对建立的六种吸附构型分别采用广义梯度近似和局域密度近似进行计算,发现三种碱金属离子均更趋向于吸附在g-C3N4片层内的大空洞中央位置(F位置)。对于碱金属与g-C3N4形成的n型Schottky结,通过能带结构和功函数的计算,发现界面电荷的平衡使g-C3N4的能带电位分别整体下移1.52 V(Li)、1.07 V(Na)、0.86 V(K)。其中K离子的引入一方面将g-C3N4的价带和导带调整到更合适的氧化还原电位,另一方面增大了g-C3N4的最高占据轨道(HOMO)和最低未占据轨道(LOMO)的分布,有利于提高载流子的迁移率,同时出现的HOMO和LOMO轨道非共面特性有利于电子和空穴的分离。

关键词: 光催化, g-C3N4, 能带结构, 载流子迁移

Abstract:

The effects of Li, Na, and K alkali metal ions on the band structures and carrier transfer of graphitic carbon nitride (g-C3N4) are investigated using the plane-wave ultrasoft pseudopotential method. The generalized gradient approximation and local density approximation are used to calculate total energies of six adsorption configurations. The three alkali ions all tend to adsorb on the large central cavity (F position) in g-C3N4 layers. The calculated band structures and work function values indicate that the interface charge balance of the n-type Schottky junctions formed between the alkali metal ions and g-C3N4 induces the total band edge potential of g-C3N4 to shift down by 1.52 V (Li), 1.07 V (Na), and 0.86 V (K). The incorporation of K ion adjusts the valence and conduction bands to more appropriate redox potentials than those of pure g-C3N4, and increases the distribution of the HOMO and LOMO of g-C3N4, which helps to improve the mobility of carriers. Meanwhile, the non-coplanar HOMO and LOMO favor the separation of electrons and holes.

Key words: Photocatalysis, g-C3N4, Band structure, Carrier transport

MSC2000: 

  • O649