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化学学报
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化学学报 ›› 2011, Vol. 69 ›› Issue (19): 2201-2206.    下一篇

研究论文

钡原子对Ru(0001)表面氮分子吸附和解离过程的影响

赵新新*,1，陶向明2，宓一鸣1，吴建宝1，汪丽莉1，谭明秋2   

  1. (1上海工程技术大学基础教学学院 上海 201620)
    (2浙江大学物理系 杭州 310027)
  • 投稿日期:2011-03-29 修回日期:2011-06-10 发布日期:2011-06-20
  • 通讯作者: 赵新新 E-mail:bighunter@sues.edu.cn
  • 基金资助:

    上海市教育委员会科研创新项目;浙江省教育厅科研项目

Effects of Barium Atoms on Adsorption and Dissociation of Nitrogen Molecules on Ru(0001) Surface

Zhao Xinxin*,1 Tao Xiangming2 Mi Yiming1 Wu Jianbao1 Wang Lili1 Tan Mingqiu2   

  1. (1 School of Fundamental Studies, Shanghai University of Engineering Science, Shanghai 201620)
    (2Department of Physics, Zhejiang University, Hangzhou 310027)
  • Received:2011-03-29 Revised:2011-06-10 Published:2011-06-20
  • Contact: Xin-Xin ZHAO E-mail:bighunter@sues.edu.cn
  • Supported by:

    The project supported by Innovation Program of Shanghai Municipal Education Commission;Research Projects of Department of Education of Zhejiang Province

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被引次数

5

采用密度泛函理论方法研究了钡原子对Ru(0001)表面氮分子解离过程的影响. 计算结果表明: 在Ru(0001)表面, 钡原子失去电子后形成Ba(1＋δ)＋阳离子. 表面转移电荷增强了衬底钌原子d轨道和氮分子π轨道间的杂化作用以及氮分子内的库仑排斥作用, 减弱了氮分子键. 在钡原子的作用下, γ态氮分子键键长从0.113 nm增加到0.123 nm, 分子拉伸振动频率从2221 cm－1减小到1745 cm－1. α态氮分子键键长从0.120 nm增加到0.133 nm, 而分子拉伸振动频率则从1486减小到1052 cm－1. 钡原子的作用使氮分子的解离反应势垒从Ru(0001)表面的2.06 eV降低到Ru(0001)-Ba表面的1.17 eV, 提高了500 K下Ru(0001)表面平台的反应活性约9个数量级. 研究结果说明, 在Ru(0001)表面金属钡原子具有电子型助催剂的特征.

关键词: 氮分子解离反应, Ru(0001), 吸附能, 分子振动, 表面电子结构

First principles calculations had been performed to present the effects of barium atom on dissociation of nitrogen molecule on Ru(0001) surface. Barium atoms became cations on Ru(0001) surface by lose electrons. Charge transfer enhanced the hybridization between d orbitals of substrate and π orbitals of nitrogen molecule. Bond strength of nitrogen molecule was weakened by effects of barium atom. Bond length of γ state nitrogen molecule was increased from 0.113 nm on Ru(0001) surface to 0.123 nm on Ru(0001)-Ba surface, and stretch vibration frequency was decreased from 2221 to 1745 cm－1. Bond length of α state nitrogen molecule was increased from 0.120 nm on Ru(0001) surface to 0.133 nm on Ru(0001)-Ba surface, and vibration frequency was decreased from 1486 to 1052 cm－1. The barrier energy of nitrogen molecular dissociation on Ru(0001) surface was reduced from 2.06 to 1.17 eV by effects of barium atom, and activities of Ru(0001) terrace surface was magnified about 9 orders at 500 K. It was indicated that barium atom had some characters to be an electronic promoter on the process of activating nitrogen molecules on Ru(0001) surface.

Key words: nitrogen dissociation, Ru(0001), adsorption energy, molecular vibration, surface electronic structure

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