Theoretical revisit of the direct synthesis of H 2O 2 on Pd and Au@Pd surfaces

A comprehensive mechanistic study

研究成果: ジャーナルへの寄稿記事

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抄録

The direct synthesis of H 2O 2 from H 2 and O 2 on Pd(111) and Au@Pd(111) surfaces is studied with periodic density functional theory calculations. Ten possible reactions and processes involved in the H 2O 2 synthesis steps are considered: For O 2, (1) O 2* + H* → OOH*, (2) O 2* → 2O*, and (3) O 2* → O 2; for OOH, (4) OOH* + H* → H 2O 2*, (5) OOH* + H* → H 2O* + O*, (6) OOH* + H* → 2OH*, (7) OOH* → O* + OH*, and (8) OOH* → OOH; for H 2O 2, (9) H 2O 2* → 2OH* and (10) H 2O 2* → H 2O 2, where the asterisks indicate these species to be surface species. All side reactions involve O-O bond dissociation. On the Pd(111) surface with H atoms coadsorbed, O 2 dissociation is suppressed; OOH dissociation is more favorable than all OOH hydrogenation reactions; three OOH hydrogenation reactions have comparable activation barriers; the barrier for H 2O 2 dissociation is also comparable to that for H 2O 2 desorption. However, on the H atoms coadsorbed Au@Pd(111) surface, the main reactions for H 2O 2 production exceed all side reactions. The competition between the main reactions and the side reactions is actually the competition between the O-O bond and the O-M bond, where M is Pd in the case of the Pd(111) surface and Au in the case of the Au@Pd(111) surface. The O-Pd bond is usually stronger than the O-O bonds in the OOH intermediate and H 2O 2; however, the O-Au bond is weaker than the O-O bonds. Consequently, the final product H 2O 2 is easily produced and released from the Au@Pd(111) surface, and the side reactions involving O-O bond dissociation are suppressed. The role of the metal surface in the direct synthesis of H 2O 2 from H 2 and O 2 is to provide H atoms as the feedstock for the hydrogenation of O 2.

元の言語英語
ページ(範囲)25359-25367
ページ数9
ジャーナルJournal of Physical Chemistry C
115
発行部数51
DOI
出版物ステータス出版済み - 12 29 2011

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synthesis
dissociation
Hydrogenation
hydrogenation
Atoms
atoms
Feedstocks
Density functional theory
Desorption
metal surfaces
Metals
Chemical activation
desorption
activation
density functional theory
products

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

これを引用

@article{9d557f114ba343efba57dd3c8f7ed260,
title = "Theoretical revisit of the direct synthesis of H 2O 2 on Pd and Au@Pd surfaces: A comprehensive mechanistic study",
abstract = "The direct synthesis of H 2O 2 from H 2 and O 2 on Pd(111) and Au@Pd(111) surfaces is studied with periodic density functional theory calculations. Ten possible reactions and processes involved in the H 2O 2 synthesis steps are considered: For O 2, (1) O 2* + H* → OOH*, (2) O 2* → 2O*, and (3) O 2* → O 2; for OOH, (4) OOH* + H* → H 2O 2*, (5) OOH* + H* → H 2O* + O*, (6) OOH* + H* → 2OH*, (7) OOH* → O* + OH*, and (8) OOH* → OOH; for H 2O 2, (9) H 2O 2* → 2OH* and (10) H 2O 2* → H 2O 2, where the asterisks indicate these species to be surface species. All side reactions involve O-O bond dissociation. On the Pd(111) surface with H atoms coadsorbed, O 2 dissociation is suppressed; OOH dissociation is more favorable than all OOH hydrogenation reactions; three OOH hydrogenation reactions have comparable activation barriers; the barrier for H 2O 2 dissociation is also comparable to that for H 2O 2 desorption. However, on the H atoms coadsorbed Au@Pd(111) surface, the main reactions for H 2O 2 production exceed all side reactions. The competition between the main reactions and the side reactions is actually the competition between the O-O bond and the O-M bond, where M is Pd in the case of the Pd(111) surface and Au in the case of the Au@Pd(111) surface. The O-Pd bond is usually stronger than the O-O bonds in the OOH intermediate and H 2O 2; however, the O-Au bond is weaker than the O-O bonds. Consequently, the final product H 2O 2 is easily produced and released from the Au@Pd(111) surface, and the side reactions involving O-O bond dissociation are suppressed. The role of the metal surface in the direct synthesis of H 2O 2 from H 2 and O 2 is to provide H atoms as the feedstock for the hydrogenation of O 2.",
author = "Jun Li and Tatsumi Ishihara and Kazunari Yoshizawa",
year = "2011",
month = "12",
day = "29",
doi = "10.1021/jp208118e",
language = "English",
volume = "115",
pages = "25359--25367",
journal = "Journal of Physical Chemistry C",
issn = "1932-7447",
publisher = "American Chemical Society",
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TY - JOUR

T1 - Theoretical revisit of the direct synthesis of H 2O 2 on Pd and Au@Pd surfaces

T2 - A comprehensive mechanistic study

AU - Li, Jun

AU - Ishihara, Tatsumi

AU - Yoshizawa, Kazunari

PY - 2011/12/29

Y1 - 2011/12/29

N2 - The direct synthesis of H 2O 2 from H 2 and O 2 on Pd(111) and Au@Pd(111) surfaces is studied with periodic density functional theory calculations. Ten possible reactions and processes involved in the H 2O 2 synthesis steps are considered: For O 2, (1) O 2* + H* → OOH*, (2) O 2* → 2O*, and (3) O 2* → O 2; for OOH, (4) OOH* + H* → H 2O 2*, (5) OOH* + H* → H 2O* + O*, (6) OOH* + H* → 2OH*, (7) OOH* → O* + OH*, and (8) OOH* → OOH; for H 2O 2, (9) H 2O 2* → 2OH* and (10) H 2O 2* → H 2O 2, where the asterisks indicate these species to be surface species. All side reactions involve O-O bond dissociation. On the Pd(111) surface with H atoms coadsorbed, O 2 dissociation is suppressed; OOH dissociation is more favorable than all OOH hydrogenation reactions; three OOH hydrogenation reactions have comparable activation barriers; the barrier for H 2O 2 dissociation is also comparable to that for H 2O 2 desorption. However, on the H atoms coadsorbed Au@Pd(111) surface, the main reactions for H 2O 2 production exceed all side reactions. The competition between the main reactions and the side reactions is actually the competition between the O-O bond and the O-M bond, where M is Pd in the case of the Pd(111) surface and Au in the case of the Au@Pd(111) surface. The O-Pd bond is usually stronger than the O-O bonds in the OOH intermediate and H 2O 2; however, the O-Au bond is weaker than the O-O bonds. Consequently, the final product H 2O 2 is easily produced and released from the Au@Pd(111) surface, and the side reactions involving O-O bond dissociation are suppressed. The role of the metal surface in the direct synthesis of H 2O 2 from H 2 and O 2 is to provide H atoms as the feedstock for the hydrogenation of O 2.

AB - The direct synthesis of H 2O 2 from H 2 and O 2 on Pd(111) and Au@Pd(111) surfaces is studied with periodic density functional theory calculations. Ten possible reactions and processes involved in the H 2O 2 synthesis steps are considered: For O 2, (1) O 2* + H* → OOH*, (2) O 2* → 2O*, and (3) O 2* → O 2; for OOH, (4) OOH* + H* → H 2O 2*, (5) OOH* + H* → H 2O* + O*, (6) OOH* + H* → 2OH*, (7) OOH* → O* + OH*, and (8) OOH* → OOH; for H 2O 2, (9) H 2O 2* → 2OH* and (10) H 2O 2* → H 2O 2, where the asterisks indicate these species to be surface species. All side reactions involve O-O bond dissociation. On the Pd(111) surface with H atoms coadsorbed, O 2 dissociation is suppressed; OOH dissociation is more favorable than all OOH hydrogenation reactions; three OOH hydrogenation reactions have comparable activation barriers; the barrier for H 2O 2 dissociation is also comparable to that for H 2O 2 desorption. However, on the H atoms coadsorbed Au@Pd(111) surface, the main reactions for H 2O 2 production exceed all side reactions. The competition between the main reactions and the side reactions is actually the competition between the O-O bond and the O-M bond, where M is Pd in the case of the Pd(111) surface and Au in the case of the Au@Pd(111) surface. The O-Pd bond is usually stronger than the O-O bonds in the OOH intermediate and H 2O 2; however, the O-Au bond is weaker than the O-O bonds. Consequently, the final product H 2O 2 is easily produced and released from the Au@Pd(111) surface, and the side reactions involving O-O bond dissociation are suppressed. The role of the metal surface in the direct synthesis of H 2O 2 from H 2 and O 2 is to provide H atoms as the feedstock for the hydrogenation of O 2.

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