Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (10): 2488-2494.doi: 10.3866/PKU.WHXB201606222

• ARTICLE • Previous Articles     Next Articles

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)

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