高等学校化学学报 ›› 2024, Vol. 45 ›› Issue (1): 20230383.doi: 10.7503/cjcu20230383

• 物理化学 • 上一篇    下一篇

二元包合水合物储氢及促进剂作用的理论研究

张宏淑1, 梁攀1,2(), 薛颖颖1, 韦瑶瑶3()   

  1. 1.陕西学前师范学院化学化工学院, 西安 710100
    2.陕西师范大学化学化工学院, 西安 710119
    3.临沂大学化学化工学院, 临沂 276000
  • 收稿日期:2023-08-29 出版日期:2024-01-10 发布日期:2023-10-25
  • 通讯作者: 梁攀,韦瑶瑶 E-mail:liangpan@snnu.edu.cn;weiyaoyao@lyu.edu.cn
  • 基金资助:
    国家自然科学基金(22003035);陕西省教育厅项目(22JK0334)

Theoretical Study on Hydrogen Storage and Promoter Effect of Binary Clathrate Hydrates

ZHANG Hongshu1, LIANG Pan1,2(), XUE Yingying1, WEI Yaoyao3()   

  1. 1.School of Chemistry and Chemical Engineering,Shaanxi Xueqian Normal University,Xi’an 710100,China
    2.School of Chemistry and Chemical Engineering,Shaanxi Normal University,Xi’an 710119,China
    3.School of Chemistry and Chemical Engineering,Linyi University,Linyi 276000,China
  • Received:2023-08-29 Online:2024-01-10 Published:2023-10-25
  • Contact: LIANG Pan, WEI Yaoyao E-mail:liangpan@snnu.edu.cn;weiyaoyao@lyu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(22003035);the Shaanxi Provincial Education Department Project, China(22JK0334)

摘要:

尽管包合水合物因其高储能密度和环境友好等优点, 可以作为大规模工业化应用的潜在储氢材料, 但在理解包合水合物中氢气的结构和扩散方面尚存在较大争议. 本文应用密度泛函理论(DFT)探讨了sI型包合水合物的储氢结构和性质. 结果表明, 纯氢气水合物中512笼中可容纳2个H2分子, CH4和C2H6促进剂对其结构和性质没有明显影响; 而在N2和CO2促进剂作用下512笼可容纳的H2分子增加到3个, 氢气水合物稳定性得到提高, 主客体间的静电和氢键相互作用增强且H—H伸缩振动峰值蓝移. 当N2和CO2包合物512笼中氢气的占据达3个H2分子时, 1个H2分子通过五边形面的扩散能垒接近于纯氢气水合物中的2倍, 有效阻碍了氢气在笼间的扩散.

关键词: 包合水合物, 储氢, 稳定性, 扩散, 促进剂作用

Abstract:

Although clathrate hydrates(CHs) can be used as potential hydrogen storage materials for large-scale industrial applications due to their high energy storage density and environmental friendliness, major gaps in the understanding of the structures and diffusion of hydrogen gas in CHs remain. Here, we theoretically explored the hydrogen storage structure and properties of type I CHs using density functional theory(DFT) calculations. The results show that up to two H2 molecules can be occupied in the 512 cages of the CHs, and the CH4 and C2H6 promoters have no significant effect on its structure and properties. However, inclusion of the N2 and CO2 promoters in the CHs cages could considerably change the structures and properties including the number of H2 molecules occupied in the 512 cages increased to three, stability increase, the host-guest electrostatic and hydrogen bonding interactions enhance, and the H—H stretching blue-shifts of the H2 molecules. Moreover, when hydrogen occupies up to three H2 molecules in the 512 cages of N2 and CO2 CHs, calculated energy barriers for one H2 molecule migration through the pentagonal surface are close to twice that of pure hydrogen CHs, effectively hindering the diffusion of hydrogen between the cages.

Key words: Clathrate hydrates, Hydrogen storage, Stability, Diffusion, Promoter effect

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