Methane Partial Oxidation over [Cu2(μ-O)]2+ and [Cu3(μ-O)3]2+ Active Species in Large-Pore Zeolites

M. Haris Mahyuddin, Takahiro Tanaka, Yoshihito Shiota, Aleksandar Tsekov Staykov, Kazunari Yoshizawa

研究成果: ジャーナルへの寄稿記事

22 引用 (Scopus)

抄録

Copper-containing large-pore zeolites, such as Cu-mordenite (Cu-MOR) and Cu-omega (Cu-MAZ), oxidize methane to yield a high amount of methanol. Two distinct active centers in MOR zeolite, namely, [Cu2(μ-O)]2+ and [Cu3(μ-O)3]2+, have been proposed and debated. In particular, the [Cu2(μ-O)]2+ species was experimentally found to be formed on two different Al pair sites with different reactivities toward methane. However, computational attempts based on density functional theory (DFT) have not been able to confirm them. Moreover, the full cycle of the reaction, which includes methane activation, water-assisted methanol desorption, and a second methane reaction with the active species, has not been well understood yet. In this study, we employed DFT calculations based on the Perdew, Burke, and Ernzerhof functional to reasonably calculate all activation energies involved in such a complete reaction over periodic systems of [Cux(μ-O)y]2+-MOR and -MAZ (x, y = 2, 1 and 3, 3) in the high-spin and low-spin states. We found two Al pair sites in MOR zeolite that form two distinct [Cu2(μ-O)]2+ structures able to cleave the C-H bond of methane with activation energies excellently comparable with the experimental values. Our computational results further suggest that the addition of a water molecule helps the reaction to reduce the high methanol desorption energies. We also show that two of the three bridging O atoms in [Cu3(μ-O)3]2+-MOR and -MAZ significantly differ in reactivity toward methane.

元の言語英語
ページ(範囲)1500-1509
ページ数10
ジャーナルACS Catalysis
8
発行部数2
DOI
出版物ステータス出版済み - 2 2 2018

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Zeolites
Methane
Oxidation
Methanol
Density functional theory
Desorption
Activation energy
Water
Time varying systems
Copper
Chemical activation
Atoms
Molecules

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

これを引用

Methane Partial Oxidation over [Cu2(μ-O)]2+ and [Cu3(μ-O)3]2+ Active Species in Large-Pore Zeolites. / Mahyuddin, M. Haris; Tanaka, Takahiro; Shiota, Yoshihito; Staykov, Aleksandar Tsekov; Yoshizawa, Kazunari.

:: ACS Catalysis, 巻 8, 番号 2, 02.02.2018, p. 1500-1509.

研究成果: ジャーナルへの寄稿記事

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title = "Methane Partial Oxidation over [Cu2(μ-O)]2+ and [Cu3(μ-O)3]2+ Active Species in Large-Pore Zeolites",
abstract = "Copper-containing large-pore zeolites, such as Cu-mordenite (Cu-MOR) and Cu-omega (Cu-MAZ), oxidize methane to yield a high amount of methanol. Two distinct active centers in MOR zeolite, namely, [Cu2(μ-O)]2+ and [Cu3(μ-O)3]2+, have been proposed and debated. In particular, the [Cu2(μ-O)]2+ species was experimentally found to be formed on two different Al pair sites with different reactivities toward methane. However, computational attempts based on density functional theory (DFT) have not been able to confirm them. Moreover, the full cycle of the reaction, which includes methane activation, water-assisted methanol desorption, and a second methane reaction with the active species, has not been well understood yet. In this study, we employed DFT calculations based on the Perdew, Burke, and Ernzerhof functional to reasonably calculate all activation energies involved in such a complete reaction over periodic systems of [Cux(μ-O)y]2+-MOR and -MAZ (x, y = 2, 1 and 3, 3) in the high-spin and low-spin states. We found two Al pair sites in MOR zeolite that form two distinct [Cu2(μ-O)]2+ structures able to cleave the C-H bond of methane with activation energies excellently comparable with the experimental values. Our computational results further suggest that the addition of a water molecule helps the reaction to reduce the high methanol desorption energies. We also show that two of the three bridging O atoms in [Cu3(μ-O)3]2+-MOR and -MAZ significantly differ in reactivity toward methane.",
author = "Mahyuddin, {M. Haris} and Takahiro Tanaka and Yoshihito Shiota and Staykov, {Aleksandar Tsekov} and Kazunari Yoshizawa",
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T1 - Methane Partial Oxidation over [Cu2(μ-O)]2+ and [Cu3(μ-O)3]2+ Active Species in Large-Pore Zeolites

AU - Mahyuddin, M. Haris

AU - Tanaka, Takahiro

AU - Shiota, Yoshihito

AU - Staykov, Aleksandar Tsekov

AU - Yoshizawa, Kazunari

PY - 2018/2/2

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N2 - Copper-containing large-pore zeolites, such as Cu-mordenite (Cu-MOR) and Cu-omega (Cu-MAZ), oxidize methane to yield a high amount of methanol. Two distinct active centers in MOR zeolite, namely, [Cu2(μ-O)]2+ and [Cu3(μ-O)3]2+, have been proposed and debated. In particular, the [Cu2(μ-O)]2+ species was experimentally found to be formed on two different Al pair sites with different reactivities toward methane. However, computational attempts based on density functional theory (DFT) have not been able to confirm them. Moreover, the full cycle of the reaction, which includes methane activation, water-assisted methanol desorption, and a second methane reaction with the active species, has not been well understood yet. In this study, we employed DFT calculations based on the Perdew, Burke, and Ernzerhof functional to reasonably calculate all activation energies involved in such a complete reaction over periodic systems of [Cux(μ-O)y]2+-MOR and -MAZ (x, y = 2, 1 and 3, 3) in the high-spin and low-spin states. We found two Al pair sites in MOR zeolite that form two distinct [Cu2(μ-O)]2+ structures able to cleave the C-H bond of methane with activation energies excellently comparable with the experimental values. Our computational results further suggest that the addition of a water molecule helps the reaction to reduce the high methanol desorption energies. We also show that two of the three bridging O atoms in [Cu3(μ-O)3]2+-MOR and -MAZ significantly differ in reactivity toward methane.

AB - Copper-containing large-pore zeolites, such as Cu-mordenite (Cu-MOR) and Cu-omega (Cu-MAZ), oxidize methane to yield a high amount of methanol. Two distinct active centers in MOR zeolite, namely, [Cu2(μ-O)]2+ and [Cu3(μ-O)3]2+, have been proposed and debated. In particular, the [Cu2(μ-O)]2+ species was experimentally found to be formed on two different Al pair sites with different reactivities toward methane. However, computational attempts based on density functional theory (DFT) have not been able to confirm them. Moreover, the full cycle of the reaction, which includes methane activation, water-assisted methanol desorption, and a second methane reaction with the active species, has not been well understood yet. In this study, we employed DFT calculations based on the Perdew, Burke, and Ernzerhof functional to reasonably calculate all activation energies involved in such a complete reaction over periodic systems of [Cux(μ-O)y]2+-MOR and -MAZ (x, y = 2, 1 and 3, 3) in the high-spin and low-spin states. We found two Al pair sites in MOR zeolite that form two distinct [Cu2(μ-O)]2+ structures able to cleave the C-H bond of methane with activation energies excellently comparable with the experimental values. Our computational results further suggest that the addition of a water molecule helps the reaction to reduce the high methanol desorption energies. We also show that two of the three bridging O atoms in [Cu3(μ-O)3]2+-MOR and -MAZ significantly differ in reactivity toward methane.

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