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基于密度泛函理论的CO2氧化含氮焦炭的机理研究

周赛 刘虎 于鹏飞 袁茂博 薛景文 车得福

周赛, 刘虎, 于鹏飞, 袁茂博, 薛景文, 车得福. 基于密度泛函理论的CO2氧化含氮焦炭的机理研究[J]. 燃料化学学报. doi: 10.19906/j.cnki.JFCT.2021061
引用本文: 周赛, 刘虎, 于鹏飞, 袁茂博, 薛景文, 车得福. 基于密度泛函理论的CO2氧化含氮焦炭的机理研究[J]. 燃料化学学报. doi: 10.19906/j.cnki.JFCT.2021061
ZHOU Sai, LIU Hu, YU Peng-fei, YUAN Mao-bo, XUE Jing-wen, CHE De-fu. Study on the mechanism of oxidation of nitrogen–containing char by CO2 based on density functional theory[J]. Journal of Fuel Chemistry and Technology. doi: 10.19906/j.cnki.JFCT.2021061
Citation: ZHOU Sai, LIU Hu, YU Peng-fei, YUAN Mao-bo, XUE Jing-wen, CHE De-fu. Study on the mechanism of oxidation of nitrogen–containing char by CO2 based on density functional theory[J]. Journal of Fuel Chemistry and Technology. doi: 10.19906/j.cnki.JFCT.2021061

基于密度泛函理论的CO2氧化含氮焦炭的机理研究

doi: 10.19906/j.cnki.JFCT.2021061
基金项目: 中国博士后科学基金(2018M633507)面上资助和陕西省自然科学基础研究计划(2020JQ-063)一般项目(青年)资助
详细信息
    通讯作者:

    Tel:15389251896,E-mail:epeliuhu@mail.xjtu.edu.cn

  • 中图分类号: TQ534.9

Study on the mechanism of oxidation of nitrogen–containing char by CO2 based on density functional theory

Funds: The project was supported by the Postdoctoral Research Foundation of China (2018M633507) and Natural Science Basic Research Plan in Shaanxi Province of China (2020JQ-063)
  • 摘要: 为深入理解煤燃烧过程中NO的生成机理,本文基于密度泛函理论,选取简化的含吡咯氮(N−5)或吡啶氮(N−6)焦炭模型,在分子水平上对CO2氧化含氮焦炭的异相反应机理进行研究。结构优化采用B3LYP–D3/6–31G(d)方法,单点能计算采用B3LYP–D3/def2–TZVP方法。计算结果表明,CO2氧化含氮焦炭过程分为CO2吸附、CO脱附和NO脱附三个阶段。CO2异相氧化含吡咯氮焦炭的反应中,CO2分子倾向于以C−O−down模式(N−O结合、C−C结合)吸附形成含氮和氧的五元杂环结构。然后五元环中原CO2分子的C−O键断裂形成表面羰基和表面氮氧结构,分别解吸附出CO和NO。该反应吸热401.2 kJ/mol,决速步能垒为197.6 kJ/mol。CO2异相氧化含吡啶氮焦炭的反应中,CO2分子以C−O−down和C−C结合、C−O结合模式吸附后倾向于先形成含氮和氧的六元杂环,再发生CO和NO分子的脱附。该反应吸收598.6 kJ/mol的热量,决速步能垒为292.0 kJ/mol。
  • 图  1  含氮焦炭模型

    Figure  1  Nitrogen–containing char models

    图  2  CO2在含N–5焦炭表面吸附的各驻点结构

    Figure  2  Structures of stagnation points of CO2 adsorption on the surface of pyrrole nitrogen–containing char

    图  3  CO2在含N–5焦炭表面吸附的能量变化

    Figure  3  Potential energy surface of CO2 adsorption on the surface of pyrrole nitrogen–containing char

    图  4  路径a反应过程的各驻点结构

    Figure  4  Structures of stagnation points of path–a

    图  5  路径a反应过程的能量变化

    Figure  5  Potential energy surface of path–a

    图  6  CO2在含N–6焦炭表面的吸附构型与能量

    Figure  6  Adsorption configuration and energy of CO2 on the surface of pyridine nitrogen–containing char

    图  7  路径c和路径d反应过程的各驻点结构

    Figure  7  Structures of stagnation points of path–c and path–d

    图  8  路径c反应过程的能量变化

    Figure  8  Potential energy surface of path–c

    图  9  路径d反应过程的能量变化

    Figure  9  Potential energy surface of path–d

    图  10  经典过渡态理论得到的反应速率常数

    Figure  10  Rate constant k calculated from cTST

    表  1  拟合所得动力学反应参数

    Table  1  Fitted kinetic parameters of Arrhenius expressions

    ReactionA /s−1Ea /kJ·mol−1
    a–IM1→a–IM27.82 × 1010186.0
    c–IM1→c–IM24.57 × 1013240.2
    IM6→P2+NO3.59 × 1015305.7
    d–IM2→d–IM35.49 × 1012598.2
    下载: 导出CSV
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  • 收稿日期:  2021-04-14
  • 修回日期:  2021-06-03
  • 网络出版日期:  2021-06-25

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