高等学校化学学报 ›› 2016, Vol. 37 ›› Issue (1): 100.doi: 10.7503/cjcu20150472

• 物理化学 • 上一篇    下一篇

外电场对锂修饰氧化石墨烯结构储氢性能的影响

赵晗1,2, 周丽娜1,3, 魏东山1(), 周新建2, 史浩飞1   

  1. 1. 中国科学院重庆绿色智能技术研究院, 跨尺度制造技术重庆市重点实验室, 重庆 400714
    2. 华东交通大学机电工程学院, 南昌 330013
    3. 河北大学化学与环境科学学院, 保定 071000
  • 收稿日期:2015-06-16 出版日期:2016-01-10 发布日期:2015-12-20
  • 基金资助:
    中国科学院“西部之光”一般项目(批准号: Y32Z030H10)、 重庆市科技攻关项目(批准号: cstc2012ggC50002, cstc2012ggC90003)和教育部留学回国人员科研启动基金资助

Effects of External Electric Field on Hydrogen Storage Performance of Li-decorated Graphene Oxide

ZHAO Han1,2, ZHOU Lina1,3, WEI Dongshan1,*(), ZHOU Xinjian2, SHI Haofei1   

  1. 1. Chongqing Key Laboratory of Multi-scale Manufacturing Technology, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
    2. College of Mechanical and Electrical Engineering, East China Jiaotong University, Nanchang 330013, China
    3.College of Chemistry & Environmental Science, Hebei University, Baoding 071000, China
  • Received:2015-06-16 Online:2016-01-10 Published:2015-12-20
  • Contact: WEI Dongshan E-mail:dswei@cigit.ac.cn
  • Supported by:
    † Supported by the West Light Foundation of the Chinese Academy of Sciences( No.Y32Z030H10 ) , the Key Scientific and Technological Projects of Chongqing, China(Nos.cstc2012ggC50002, cstc2012ggC90003) and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education, China

摘要:

基于密度泛函理论(DFT)的第一性原理方法, 研究了外加电场对锂修饰氧化石墨烯结构(Li@GO)储氢性能的影响. 考察Li@GO结构的稳定性及其对外加电场的响应, 研究H2-Li@GO结构的H2分子吸附能、 几何构型与外加电场的关系. 研究结果表明, 当外加电场方向垂直Li@GO平面向下(负电场)时, 随电场强度增加, H2分子的吸附能逐渐降低, H2分子逐渐接近Li原子; 当外加电场方向向上(正电场)时, 随电场强度增加, H2分子的吸附能逐渐升高, H2分子逐渐远离Li原子. 分波态密度(PDOS)分析表明: 与无外加电场体系的PDOS相比, 当对体系施加负电场时, H2-Li的杂化峰向低能量方向位移, H2分子与Li@GO结合更加紧密, 提升了储氢稳定性; 施加正电场时, H2-Li的杂化峰向高能量方向位移, H2分子与Li@GO作用减弱, 提升了氢气释放动力学性能. 进一步计算表明, 在无外加电场情况下, Li@GO结构最大储氢量在3.1%以上.

关键词: 氧化石墨烯, 储氢性能, 外电场, 密度泛函理论, 吸附能, 分波态密度

Abstract:

Hydrogen storage performance of Li decorated graphene oxide(GO) under an external electric field was investigated with the first-principle method based on the density functional theory(DFT) calculations. Firstly the stability of Li@GO structure due to the adsorption of Li atoms at different binding sites on GO structure was investigated. Then a stable Li@GO structure was obtained and dependences of the structural stability and H2 adsorption of the Li@GO structure on the electric field were discussed. The results indicate that both the H2 adsorption energy, Ead, and the distance between H2 and Li atom, d(Li-H2), decrease with the increasing intensity of the downward electric field. While both Ead and d(Li-H2) increase with the increasing intensity of the upward electric field. From the partial density of state(PDOS) analysis, the H2-Li hybridization peaks under a negative electric field shifted to the larger negative energy region compared to those without an electric field, which indicates the H2-Li@GO system becomes more stable under the negative electric field. When the positive electric field was added, the H2-Li hybridization peaks shifted to the smaller negative energy region, which indicates the interaction between H2 and Li becomes weaker. It is therefore anticipated that the adsorption-desorption processes of H2 on Li@GO structure can be easily controlled by adding an electric field with appropriate intensity and direction. Further calculation indicates the Li@GO structure has a maximum hydrogen storage capability of larger than 3.1% without the external electric field.

Key words: Graphene oxide, Hydrogen storage performance, Electric field, Density functional theory, Adsorption energy, Partial density of state

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