中国物理B ›› 2023, Vol. 32 ›› Issue (10): 108103-108103.doi: 10.1088/1674-1056/acd2b3

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Activated dissociation of H2 on the Cu(001) surface: The role of quantum tunneling

Xiaofan Yu(于小凡)1,2,†, Yangwu Tong(童洋武)1,2,†, and Yong Yang(杨勇)1,2,‡   

  1. 1 Key Laboratory of Photovoltaic and Energy Conservation Materials, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China;
    2 Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, China
  • 收稿日期:2023-02-28 修回日期:2023-04-30 接受日期:2023-05-05 出版日期:2023-09-21 发布日期:2023-09-22
  • 通讯作者: Yong Yang E-mail:yyanglab@issp.ac.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11474285 and 12074382). We are grateful to the staffs at the Hefei Branch of Supercomputing Center of Chinese Academy of Sciences, and the Hefei Advanced Computing Center for the support of supercomputing facilities.

Activated dissociation of H2 on the Cu(001) surface: The role of quantum tunneling

Xiaofan Yu(于小凡)1,2,†, Yangwu Tong(童洋武)1,2,†, and Yong Yang(杨勇)1,2,‡   

  1. 1 Key Laboratory of Photovoltaic and Energy Conservation Materials, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China;
    2 Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, China
  • Received:2023-02-28 Revised:2023-04-30 Accepted:2023-05-05 Online:2023-09-21 Published:2023-09-22
  • Contact: Yong Yang E-mail:yyanglab@issp.ac.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11474285 and 12074382). We are grateful to the staffs at the Hefei Branch of Supercomputing Center of Chinese Academy of Sciences, and the Hefei Advanced Computing Center for the support of supercomputing facilities.

摘要: The activation and dissociation of hydrogen molecules (H2) on the Cu(001) surface are studied theoretically. Using first-principles calculations, the activation barrier for the dissociation of H2 on Cu(001) is determined to be ~ 0.59 eV in height. It is found that the electron transfer from the copper substrate to H2 plays a key role in the activation and breaking of the H-H bond, and the formation of the Cu-H bonds. Two stationary states are identified at around the critical height of bond breaking, corresponding to the molecular and the dissociative states, respectively. Using the transfer matrix method, we also investigate the role of quantum tunneling in the dissociation process along the minimum energy pathway (MEP), which is found to be significant at or below room temperature. At a given temperature, the tunneling contributions due to the translational and the vibrational motions of H2 are quantified for the dissociation process. Within a wide range of temperature, the effects of quantum tunneling on the effective barriers of dissociation and the rate constants are observed. The deduced energetic parameters associated with the thermal equilibrium and non-equilibrium (molecular beam) conditions are comparable to experimental data. In the low-temperature region, the crossover from classical to quantum regime is identified.

关键词: H2, Cu(001), dissociation, quantum tunneling, density functional theory (DFT), transfer matrix method

Abstract: The activation and dissociation of hydrogen molecules (H2) on the Cu(001) surface are studied theoretically. Using first-principles calculations, the activation barrier for the dissociation of H2 on Cu(001) is determined to be ~ 0.59 eV in height. It is found that the electron transfer from the copper substrate to H2 plays a key role in the activation and breaking of the H-H bond, and the formation of the Cu-H bonds. Two stationary states are identified at around the critical height of bond breaking, corresponding to the molecular and the dissociative states, respectively. Using the transfer matrix method, we also investigate the role of quantum tunneling in the dissociation process along the minimum energy pathway (MEP), which is found to be significant at or below room temperature. At a given temperature, the tunneling contributions due to the translational and the vibrational motions of H2 are quantified for the dissociation process. Within a wide range of temperature, the effects of quantum tunneling on the effective barriers of dissociation and the rate constants are observed. The deduced energetic parameters associated with the thermal equilibrium and non-equilibrium (molecular beam) conditions are comparable to experimental data. In the low-temperature region, the crossover from classical to quantum regime is identified.

Key words: H2, Cu(001), dissociation, quantum tunneling, density functional theory (DFT), transfer matrix method

中图分类号:  (Single molecule reaction kinetics, dissociation, etc.)

  • 82.37.Np
82.65.+r (Surface and interface chemistry; heterogeneous catalysis at surfaces) 68.43.-h (Chemisorption/physisorption: adsorbates on surfaces) 66.35.+a (Quantum tunneling of defects)