辽宁石油化工大学学报

辽宁石油化工大学学报 ›› 2018, Vol. 38 ›› Issue (06): 37-42.DOI: 10.3969/j.issn.1672-6952.2018.06.007

• 材料科学与新能源 • 上一篇    下一篇

碱金属改性g-C3N4及其对氮气吸附影响的理论研究

李强1李晴1,2吕扬1王焕1,3秦玉才1宋丽娟1,3胡绍争1   

  1. 1.辽宁石油化工大学 辽宁省石油化工催化科学与技术重点实验室,辽宁 抚顺 113001;2.中国石油大学(北京) 提高采收率研究院,北京 102249;3.中国石油大学(华东) 化学工程学院,山东 青岛 266580
  • 收稿日期:2018-09-14 修回日期:2018-09-25 出版日期:2018-12-01 发布日期:2018-12-11
  • 作者简介:李强(1984-),男,博士,讲师,从事理论催化方面的研究;E-mail:liqiang@lnpu.edu.cn。
  • 基金资助:
    辽宁省自然科学基金指导计划项目(201602467);辽宁石油化工大学引进人才科研启动基金项目(2016XJJ-016)。

Theoretical Study of Alkali Metal Modified g-C3N4 and Its Influence on Nitrogen Adsorption

Li Qiang1Li Qing1,2,Lü Yang1Wang Huan1,3Qin Yucai1Song Lijuan1,3Hu Shaozheng1   

  1. 1.Liaoning Provincial Key Laboratory of Petrochemical Catalytic Science and Technology,Liaoning Shihua University,Fushun Liaoning 113001,China;2.Enhanced Oil Recovery Institute,China University of Petroleum (Beijing),Beijing 102249,China;3.College of Chemical Engineering,China University of Petroleum (East China),Qingdao Shandong 266580,China
  • Received:2018-09-14 Revised:2018-09-25 Published:2018-12-01 Online:2018-12-11

摘要: 研究了碱金属改性对g-C3N4光催化剂的影响,利用密度泛函理论从几何和电子结构的角度阐述了不同碱金属改性对提高光催化活性的微观机理。结果表明,Li、Na、K、Rb原子随着核外电子层数的增加,碱金属和g-C3N4的结合能越来越弱,对g-C3N4结构的影响也越来越弱。电子结构分析可知,Li、Na、K原子对g-C3N4具有活化作用,Rb原子对g-C3N4表面有钝化作用。同时模拟了N2分子在M-g-C3N4 (M=Li、Na、K、Rb)上的吸附,理解N2分子与碱金属之间的作用机理,通过分析N2吸附的吸附能、结构参数和电子特性,发现Li、Na原子对N2吸附的影响更大,N2的N—N键长伸长,K和Rb原子对N2基本没有作用。碱金属改性g-C3N4比纯g-C3N4更有利于N2分子的吸附,但是随着碱金属原子半径的增加,吸附能力越来越弱,电子的转移也越来越少,即活化N2分子的能力按照Li、Na、K、Rb的顺序降低。

关键词: 密度泛函理论, g-C3N4, 碱金属改性, 氮气吸附

Abstract: The effect of alkali metal modification on g-C3N4 photocatalyst was systematically studied. The density functional theory is used to explain the microscopic mechanism of different alkali metal modification on improving photocatalytic activity from the various angles of geometry and electronic structure. The results show that the binding energies of alkali metals and g-C3N4 become weaker and weaker with the increase of the number of extra-nuclear electronic layers of Li, Na, K and Rb atoms, and the influence on the structure of g-C3N4 is weaker and weaker. The electronic structure analysis shows that Li, Na, and K atoms have an activation effect on g-C3N4, and Rb atoms have a passivation effect on the surface of g-C3N4. At the same time, the adsorption of N2 molecules on M-g-C3N4 (M=Li, Na, K, Rb) is simulated, and the interaction mechanism between N2 molecules and alkali metals is understood. By analyzing the adsorption energy, structural parameters and electronic properties of N2 adsorption, it is found that the influence of Li and Na atoms on N2 adsorption is greater. The N—N bond of N2 is elongated, and the K and Rb atoms have little effect on N2. Alkali metal modified g-C3N4 is more beneficial for the adsorption of N2 molecules than pure g-C3N4, but as the atomic radius of the alkali metal increases, the adsorption capacity becomes weaker and weaker, and the electron transfer becomes less and less. That is to say, the ability of activating N2 molecule decreases in the order of Li, Na, K and Rb.

Key words: Density functional theory, Graphite phase carbon nitride, Alkali metal modification, N2 molecular adsorption

引用本文

李强,李晴,吕扬,王焕,秦玉才,宋丽娟,胡绍争. 碱金属改性g-C3N4及其对氮气吸附影响的理论研究[J]. 辽宁石油化工大学学报, 2018, 38(06): 37-42.

Li Qiang,Li Qing,Lü Yang,Wang Huan,Qin Yucai,Song Lijuan,Hu Shaozheng. Theoretical Study of Alkali Metal Modified g-C3N4 and Its Influence on Nitrogen Adsorption[J]. Journal of Liaoning Petrochemical University, 2018, 38(06): 37-42.

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链接本文: http://journal.lnpu.edu.cn/CN/10.3969/j.issn.1672-6952.2018.06.007

               http://journal.lnpu.edu.cn/CN/Y2018/V38/I06/37