Properties of immobile hydrogen confined in microporous carbon

Jitendra Bahadur; Cristian I. Contescu; Anibal J. Ramirez-Cuesta; Eugene Mamontov; Nidia C. Gallego; Yongqiang Cheng; Luke L. Daemen; Yuri B. Melnichenko

doi:10.1016/j.carbon.2017.03.007

Properties of immobile hydrogen confined in microporous carbon

Jitendra Bahadur, Cristian I. Contescu, Anibal J. Ramirez-Cuesta, Eugene Mamontov, Nidia C. Gallego, Yongqiang Cheng, Luke L. Daemen, Yuri B. Melnichenko

Research output: Contribution to journal › Article › peer-review

18 Scopus citations

Abstract

We report results of vibrational neutron spectroscopy investigation aimed to identify the state of hydrogen adsorbed in ultramicroporous carbon. The mobility of hydrogen confined in carbon pores was probed as a function of temperature and pressure using inelastic neutron scattering, and the molecular translational and rotational motions were studied. At low loading rotation of H₂ molecules adsorbed in the smallest carbon pores (∼4–5 Å) is severely hindered, suggesting that the interaction between H₂ and the host matrix is anisotropic. At higher loading, H₂ molecules behave as a nearly free rotor, implying lower anisotropic interactions with adsorption sites. At 77 K where bulk H₂ is a gas, deconvolution of elastic/quasielastic signal provide evidence of pressure-dependent fractions of immobile (solid-like) and partially mobile (liquid-like) hydrogen, which correlate with the excess adsorption isotherm at 77 K. Effective H₂ density in pores changes from solid-like to liquid-like with increasing pressure at 77 K. Surprisingly, immobile and partially mobile H₂ is present even at temperatures as high as ∼110 K where bulk hydrogen exists only in gas form.

Original language	English
Pages (from-to)	383-392
Number of pages	10
Journal	Carbon
Volume	117
DOIs	https://doi.org/10.1016/j.carbon.2017.03.007
State	Published - Jun 1 2017

Funding

The research at ORNL's Spallation Neutron Source was supported by the Scientific User Facilities Division, Office of Basic Energy Sciences, U. S. Department of Energy. This research was supported in part by the ORNL Postdoctoral Research Associates Program, administered jointly by the ORNL and the Oak Ridge Institute for Science and Education. CIC and NCG acknowledge support from the Materials Science and Engineering Division, Office of Basic Energy Sciences, U.S. Department of Energy under contract number DE-AC05-00OR22725. The authors thank one anonymous reviewer for constructive queries and suggestions that helped raised the quality of the manuscript. This work was enthusiastically supported by the late Dr. Yuri Melnichenko, who unfortunately did not live to see the results.

Funders	Funder number
Scientific User Facilities Division
U.S. Department of Energy	DE-AC05-00OR22725
Basic Energy Sciences
Oak Ridge National Laboratory
Oak Ridge Institute for Science and Education
Division of Materials Sciences and Engineering

Access to Document

10.1016/j.carbon.2017.03.007

Cite this

@article{9cb2852e53c8449ca86f4dbdca01a25f,

title = "Properties of immobile hydrogen confined in microporous carbon",

abstract = "We report results of vibrational neutron spectroscopy investigation aimed to identify the state of hydrogen adsorbed in ultramicroporous carbon. The mobility of hydrogen confined in carbon pores was probed as a function of temperature and pressure using inelastic neutron scattering, and the molecular translational and rotational motions were studied. At low loading rotation of H2 molecules adsorbed in the smallest carbon pores (∼4–5 {\AA}) is severely hindered, suggesting that the interaction between H2 and the host matrix is anisotropic. At higher loading, H2 molecules behave as a nearly free rotor, implying lower anisotropic interactions with adsorption sites. At 77 K where bulk H2 is a gas, deconvolution of elastic/quasielastic signal provide evidence of pressure-dependent fractions of immobile (solid-like) and partially mobile (liquid-like) hydrogen, which correlate with the excess adsorption isotherm at 77 K. Effective H2 density in pores changes from solid-like to liquid-like with increasing pressure at 77 K. Surprisingly, immobile and partially mobile H2 is present even at temperatures as high as ∼110 K where bulk hydrogen exists only in gas form.",

author = "Jitendra Bahadur and Contescu, {Cristian I.} and Ramirez-Cuesta, {Anibal J.} and Eugene Mamontov and Gallego, {Nidia C.} and Yongqiang Cheng and Daemen, {Luke L.} and Melnichenko, {Yuri B.}",

note = "Publisher Copyright: {\textcopyright} 2017 Elsevier Ltd",

year = "2017",

month = jun,

day = "1",

doi = "10.1016/j.carbon.2017.03.007",

language = "English",

volume = "117",

pages = "383--392",

journal = "Carbon",

issn = "0008-6223",

publisher = "Elsevier",

}

TY - JOUR

T1 - Properties of immobile hydrogen confined in microporous carbon

AU - Bahadur, Jitendra

AU - Contescu, Cristian I.

AU - Ramirez-Cuesta, Anibal J.

AU - Mamontov, Eugene

AU - Gallego, Nidia C.

AU - Cheng, Yongqiang

AU - Daemen, Luke L.

AU - Melnichenko, Yuri B.

PY - 2017/6/1

Y1 - 2017/6/1

N2 - We report results of vibrational neutron spectroscopy investigation aimed to identify the state of hydrogen adsorbed in ultramicroporous carbon. The mobility of hydrogen confined in carbon pores was probed as a function of temperature and pressure using inelastic neutron scattering, and the molecular translational and rotational motions were studied. At low loading rotation of H2 molecules adsorbed in the smallest carbon pores (∼4–5 Å) is severely hindered, suggesting that the interaction between H2 and the host matrix is anisotropic. At higher loading, H2 molecules behave as a nearly free rotor, implying lower anisotropic interactions with adsorption sites. At 77 K where bulk H2 is a gas, deconvolution of elastic/quasielastic signal provide evidence of pressure-dependent fractions of immobile (solid-like) and partially mobile (liquid-like) hydrogen, which correlate with the excess adsorption isotherm at 77 K. Effective H2 density in pores changes from solid-like to liquid-like with increasing pressure at 77 K. Surprisingly, immobile and partially mobile H2 is present even at temperatures as high as ∼110 K where bulk hydrogen exists only in gas form.

AB - We report results of vibrational neutron spectroscopy investigation aimed to identify the state of hydrogen adsorbed in ultramicroporous carbon. The mobility of hydrogen confined in carbon pores was probed as a function of temperature and pressure using inelastic neutron scattering, and the molecular translational and rotational motions were studied. At low loading rotation of H2 molecules adsorbed in the smallest carbon pores (∼4–5 Å) is severely hindered, suggesting that the interaction between H2 and the host matrix is anisotropic. At higher loading, H2 molecules behave as a nearly free rotor, implying lower anisotropic interactions with adsorption sites. At 77 K where bulk H2 is a gas, deconvolution of elastic/quasielastic signal provide evidence of pressure-dependent fractions of immobile (solid-like) and partially mobile (liquid-like) hydrogen, which correlate with the excess adsorption isotherm at 77 K. Effective H2 density in pores changes from solid-like to liquid-like with increasing pressure at 77 K. Surprisingly, immobile and partially mobile H2 is present even at temperatures as high as ∼110 K where bulk hydrogen exists only in gas form.

UR - http://www.scopus.com/inward/record.url?scp=85014821790&partnerID=8YFLogxK

U2 - 10.1016/j.carbon.2017.03.007

DO - 10.1016/j.carbon.2017.03.007

M3 - Article

AN - SCOPUS:85014821790

SN - 0008-6223

VL - 117

SP - 383

EP - 392

JO - Carbon

JF - Carbon

ER -

Properties of immobile hydrogen confined in microporous carbon

Abstract

Funding

Access to Document

Other files and links

Fingerprint

Cite this