Water reaction mechanism in metal organic frameworks with coordinatively unsaturated metal ions: MOF-74

Kui Tan, Sebastian Zuluaga, Qihan Gong, Pieremanuele Canepa, Hao Wang, Jing Li, Yves J. Chabal, Timo Thonhauser

Research output: Contribution to journalArticle

57 Citations (Scopus)

Abstract

Water dissociation represents one of the most important reactions in catalysis, essential to the surface and nano sciences [e.g., Hass et al., Science, 1998, 282, 265-268; Brown et al., Science, 2001, 294, 67-69; Bikondoa et al., Nature, 2005, 5, 189-192 ]. However, the dissociation mechanism on most oxide surfaces is not well understood due to the experimental challenges of preparing surface structures and characterizing reaction pathways. To remedy this problem, we propose the metal organic framework MOF-74 as an ideal model system to study water reactions. Its crystalline structure is well characterized; the metal oxide node mimics surfaces with exposed cations; and it degrades in water. Combining in situ IR spectroscopy and first-principles calculations, we explored the MOF-74/water interaction as a function of vapor pressure and temperature. Here, we show that, while adsorption is reversible below the water condensation pressure (∼19.7 Torr) at room temperature, a reaction takes place at ∼150 °C even at low water vapor pressures. This important finding is unambiguously demonstrated by a clear spectroscopic signature of the direct reaction using D2O, which is not present using H2O due to strong phonon coupling. Specifically, a sharp absorption band appears at 970 cm-1 when D2O is introduced at above 150 °C, which we attribute to an O-D bending vibration on the phenolate linker. Although H2O undergoes a similar dissociation reaction, the corresponding O-H mode is too strongly coupled to MOF vibrations to detect. In contrast, the O-D mode falls in the phonon gap of the MOF and remains localized. First-principles calculations not only positively identify the O-D mode at 970 cm-1 but derive a pathway and kinetic barrier for the reaction and the final configuration: the D (H) atom is transferred to the oxygen of the linker phenolate group, producing the notable O-D absorption band at 970 cm-1, while the OD (or OH) binds to the open metal sites. This finding explains water dissociation in this case and provides insight into the long-lasting question of MOF-74 degradation. Overall, it adds to the understanding of molecular water interaction with cation-exposed surfaces to enable development of more efficient catalysts for water dissociation.

Original languageEnglish
Pages (from-to)6886-6895
Number of pages10
JournalChemistry of Materials
Volume26
Issue number23
DOIs
Publication statusPublished - Dec 1 2014

Fingerprint

Metal ions
Metals
Water
Vapor pressure
Oxides
Cations
Absorption spectra
Positive ions
Steam
Surface structure
Water vapor
Catalysis
Condensation
Infrared spectroscopy
Oxygen
Crystalline materials
Adsorption
Degradation
Atoms
Temperature

ASJC Scopus subject areas

  • Materials Chemistry
  • Chemical Engineering(all)
  • Chemistry(all)

Cite this

Water reaction mechanism in metal organic frameworks with coordinatively unsaturated metal ions : MOF-74. / Tan, Kui; Zuluaga, Sebastian; Gong, Qihan; Canepa, Pieremanuele; Wang, Hao; Li, Jing; Chabal, Yves J.; Thonhauser, Timo.

In: Chemistry of Materials, Vol. 26, No. 23, 01.12.2014, p. 6886-6895.

Research output: Contribution to journalArticle

Tan, K, Zuluaga, S, Gong, Q, Canepa, P, Wang, H, Li, J, Chabal, YJ & Thonhauser, T 2014, 'Water reaction mechanism in metal organic frameworks with coordinatively unsaturated metal ions: MOF-74', Chemistry of Materials, vol. 26, no. 23, pp. 6886-6895. https://doi.org/10.1021/cm5038183
Tan, Kui ; Zuluaga, Sebastian ; Gong, Qihan ; Canepa, Pieremanuele ; Wang, Hao ; Li, Jing ; Chabal, Yves J. ; Thonhauser, Timo. / Water reaction mechanism in metal organic frameworks with coordinatively unsaturated metal ions : MOF-74. In: Chemistry of Materials. 2014 ; Vol. 26, No. 23. pp. 6886-6895.
@article{b2785a94497b4f2b809e55d60967f449,
title = "Water reaction mechanism in metal organic frameworks with coordinatively unsaturated metal ions: MOF-74",
abstract = "Water dissociation represents one of the most important reactions in catalysis, essential to the surface and nano sciences [e.g., Hass et al., Science, 1998, 282, 265-268; Brown et al., Science, 2001, 294, 67-69; Bikondoa et al., Nature, 2005, 5, 189-192 ]. However, the dissociation mechanism on most oxide surfaces is not well understood due to the experimental challenges of preparing surface structures and characterizing reaction pathways. To remedy this problem, we propose the metal organic framework MOF-74 as an ideal model system to study water reactions. Its crystalline structure is well characterized; the metal oxide node mimics surfaces with exposed cations; and it degrades in water. Combining in situ IR spectroscopy and first-principles calculations, we explored the MOF-74/water interaction as a function of vapor pressure and temperature. Here, we show that, while adsorption is reversible below the water condensation pressure (∼19.7 Torr) at room temperature, a reaction takes place at ∼150 °C even at low water vapor pressures. This important finding is unambiguously demonstrated by a clear spectroscopic signature of the direct reaction using D2O, which is not present using H2O due to strong phonon coupling. Specifically, a sharp absorption band appears at 970 cm-1 when D2O is introduced at above 150 °C, which we attribute to an O-D bending vibration on the phenolate linker. Although H2O undergoes a similar dissociation reaction, the corresponding O-H mode is too strongly coupled to MOF vibrations to detect. In contrast, the O-D mode falls in the phonon gap of the MOF and remains localized. First-principles calculations not only positively identify the O-D mode at 970 cm-1 but derive a pathway and kinetic barrier for the reaction and the final configuration: the D (H) atom is transferred to the oxygen of the linker phenolate group, producing the notable O-D absorption band at 970 cm-1, while the OD (or OH) binds to the open metal sites. This finding explains water dissociation in this case and provides insight into the long-lasting question of MOF-74 degradation. Overall, it adds to the understanding of molecular water interaction with cation-exposed surfaces to enable development of more efficient catalysts for water dissociation.",
author = "Kui Tan and Sebastian Zuluaga and Qihan Gong and Pieremanuele Canepa and Hao Wang and Jing Li and Chabal, {Yves J.} and Timo Thonhauser",
year = "2014",
month = "12",
day = "1",
doi = "10.1021/cm5038183",
language = "English",
volume = "26",
pages = "6886--6895",
journal = "Chemistry of Materials",
issn = "0897-4756",
publisher = "American Chemical Society",
number = "23",

}

TY - JOUR

T1 - Water reaction mechanism in metal organic frameworks with coordinatively unsaturated metal ions

T2 - MOF-74

AU - Tan, Kui

AU - Zuluaga, Sebastian

AU - Gong, Qihan

AU - Canepa, Pieremanuele

AU - Wang, Hao

AU - Li, Jing

AU - Chabal, Yves J.

AU - Thonhauser, Timo

PY - 2014/12/1

Y1 - 2014/12/1

N2 - Water dissociation represents one of the most important reactions in catalysis, essential to the surface and nano sciences [e.g., Hass et al., Science, 1998, 282, 265-268; Brown et al., Science, 2001, 294, 67-69; Bikondoa et al., Nature, 2005, 5, 189-192 ]. However, the dissociation mechanism on most oxide surfaces is not well understood due to the experimental challenges of preparing surface structures and characterizing reaction pathways. To remedy this problem, we propose the metal organic framework MOF-74 as an ideal model system to study water reactions. Its crystalline structure is well characterized; the metal oxide node mimics surfaces with exposed cations; and it degrades in water. Combining in situ IR spectroscopy and first-principles calculations, we explored the MOF-74/water interaction as a function of vapor pressure and temperature. Here, we show that, while adsorption is reversible below the water condensation pressure (∼19.7 Torr) at room temperature, a reaction takes place at ∼150 °C even at low water vapor pressures. This important finding is unambiguously demonstrated by a clear spectroscopic signature of the direct reaction using D2O, which is not present using H2O due to strong phonon coupling. Specifically, a sharp absorption band appears at 970 cm-1 when D2O is introduced at above 150 °C, which we attribute to an O-D bending vibration on the phenolate linker. Although H2O undergoes a similar dissociation reaction, the corresponding O-H mode is too strongly coupled to MOF vibrations to detect. In contrast, the O-D mode falls in the phonon gap of the MOF and remains localized. First-principles calculations not only positively identify the O-D mode at 970 cm-1 but derive a pathway and kinetic barrier for the reaction and the final configuration: the D (H) atom is transferred to the oxygen of the linker phenolate group, producing the notable O-D absorption band at 970 cm-1, while the OD (or OH) binds to the open metal sites. This finding explains water dissociation in this case and provides insight into the long-lasting question of MOF-74 degradation. Overall, it adds to the understanding of molecular water interaction with cation-exposed surfaces to enable development of more efficient catalysts for water dissociation.

AB - Water dissociation represents one of the most important reactions in catalysis, essential to the surface and nano sciences [e.g., Hass et al., Science, 1998, 282, 265-268; Brown et al., Science, 2001, 294, 67-69; Bikondoa et al., Nature, 2005, 5, 189-192 ]. However, the dissociation mechanism on most oxide surfaces is not well understood due to the experimental challenges of preparing surface structures and characterizing reaction pathways. To remedy this problem, we propose the metal organic framework MOF-74 as an ideal model system to study water reactions. Its crystalline structure is well characterized; the metal oxide node mimics surfaces with exposed cations; and it degrades in water. Combining in situ IR spectroscopy and first-principles calculations, we explored the MOF-74/water interaction as a function of vapor pressure and temperature. Here, we show that, while adsorption is reversible below the water condensation pressure (∼19.7 Torr) at room temperature, a reaction takes place at ∼150 °C even at low water vapor pressures. This important finding is unambiguously demonstrated by a clear spectroscopic signature of the direct reaction using D2O, which is not present using H2O due to strong phonon coupling. Specifically, a sharp absorption band appears at 970 cm-1 when D2O is introduced at above 150 °C, which we attribute to an O-D bending vibration on the phenolate linker. Although H2O undergoes a similar dissociation reaction, the corresponding O-H mode is too strongly coupled to MOF vibrations to detect. In contrast, the O-D mode falls in the phonon gap of the MOF and remains localized. First-principles calculations not only positively identify the O-D mode at 970 cm-1 but derive a pathway and kinetic barrier for the reaction and the final configuration: the D (H) atom is transferred to the oxygen of the linker phenolate group, producing the notable O-D absorption band at 970 cm-1, while the OD (or OH) binds to the open metal sites. This finding explains water dissociation in this case and provides insight into the long-lasting question of MOF-74 degradation. Overall, it adds to the understanding of molecular water interaction with cation-exposed surfaces to enable development of more efficient catalysts for water dissociation.

UR - http://www.scopus.com/inward/record.url?scp=84916226608&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84916226608&partnerID=8YFLogxK

U2 - 10.1021/cm5038183

DO - 10.1021/cm5038183

M3 - Article

AN - SCOPUS:84916226608

VL - 26

SP - 6886

EP - 6895

JO - Chemistry of Materials

JF - Chemistry of Materials

SN - 0897-4756

IS - 23

ER -