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首页> 外文期刊>Applied Surface Science >Role of CO2 in the oxy-dehydrogenation of ethylbenzene to styrene on the CeO2(111) surface
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Role of CO2 in the oxy-dehydrogenation of ethylbenzene to styrene on the CeO2(111) surface

机译：CO2在CeO2（111）表面上将乙苯氧化脱氢为苯乙烯的作用

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摘要

The role of CO2 in the ethylbenzene oxy-dehydrogenation to styrene on the CeO2(111) surface was thoroughly investigated by the density functional theory (DFT) calculations. Results show that the first CH bond of ethylbenzene is activated via the oxo-insertion with a barrier of 1.70 eV, resulting in a 2-phenylethyl species and an H atom adsorbed on two-adjacent-lattice oxygen. The H adatom forms a hydroxyl-like species (denoted as O*H). The subsequent dehydrogenation to styrene can be assisted by either the next lattice oxygen (pathway R1) or the O*H species (pathway R2). The two pathways have almost the same activation energy (0.84 eV for R1 and 0.85 eV for R2), forming a new O*H and desorbing a H2O molecule while leaving an oxygen vacancy on the surface, respectively. In the presence of CO2, it will react with O*H through the reverse water gas shift reaction with an activation barrier of 0.98 eV and reaction energy of 0.30 eV. The reverse water gas shift reaction helps to clear the H adatoms from the lattice oxygen, thereby competing with styrene formation via pathway R2. However, the activation energy following the reverse water gas shift mechanism is 0.13 eV higher than that of styrene formation via pathway R2. Therefore, the formation of oxygen vacancy cannot be inhibited, while CO2 can react with the surface oxygen vacancy to produce CO with a high activation energy of 2.10 eV. (C) 2017 Elsevier B.V. All rights reserved.
机译：通过密度泛函理论（DFT）计算，深入研究了CO2在CeO2（111）表面上的乙苯氧基脱氢成苯乙烯的作用。结果表明，乙苯的第一个CH键通过1.70 eV的势垒通过氧代插入被激活，从而产生一个2-苯基乙基物质和一个氢原子吸附在两个相邻的晶格氧上。 H原子形成羟基样物质（表示为O * H）。随后的下一个晶格氧（途径R1）或O * H物质（途径R2）可协助将苯乙烯脱氢成苯乙烯。这两个途径具有几乎相同的活化能（R1为0.84 eV，R2为0.85 eV），形成新的O * H并解吸H2O分子，同时在表面上留下氧空位。在存在CO2的情况下，它将通过反向水煤气变换反应与O * H反应，活化能垒为0.98 eV，反应能为0.30 eV。反向的水煤气变换反应有助于从晶格氧中清除H原子，从而通过途径R2与苯乙烯竞争。但是，遵循反向水煤气变换机理的活化能比通过途径R2形成的苯乙烯活化能高0.13 eV。因此，不能抑制氧空位的形成，而CO 2可以与表面氧空位反应以产生具有2.10eV的高活化能的CO。 （C）2017 Elsevier B.V.保留所有权利。

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  • 来源
    《Applied Surface Science》 |2018年第ptab期|973-980|共8页
  • 作者

    Fan Hong-Xia; Feng Jie; Li Wen-Ying; Li Xiao-Hong; Wiltowski Tomasz; Ge Qing-Feng;

  • 作者单位

    Taiyuan Univ Technol, Training Base State Key Lab Coal Sci & Technol Jo, Taiyuan 030024, Shanxi, Peoples R China;

    Taiyuan Univ Technol, Training Base State Key Lab Coal Sci & Technol Jo, Taiyuan 030024, Shanxi, Peoples R China;

    Taiyuan Univ Technol, Training Base State Key Lab Coal Sci & Technol Jo, Taiyuan 030024, Shanxi, Peoples R China;

    Taiyuan Univ Technol, Training Base State Key Lab Coal Sci & Technol Jo, Taiyuan 030024, Shanxi, Peoples R China;

    Southern Illinois Univ, Adv Coal & Energy Res Ctr, Carbondale, IL 62901 USA;

    Southern Illinois Univ, Dept Chem & Biochem, Carbondale, IL 62901 USA;

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  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Ethylbenzene; Oxy-dehydrogenation; CO2; DFT calculations; CeO2(111); surface;

    机译：乙苯;氧化脱氢;CO2;DFT计算;CeO2（111）;表面;

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