Doctoral Dissertations

Keywords and Phrases

Doped Carbon; Energy Storage; Hydrogen Storage; Metal Hydrides; Nanoconfinement; Nanoporous Carbon

Abstract

"Recent efforts have demonstrated confinement in porous scaffolds at the nanoscale can alter the hydrogen sorption properties of metal hydrides, though not to an extent feasible for use in onboard hydrogen storage applications, proposing the need for a method allowing further modifications. The work presented here explores how the functionalization of nanoporous carbon scaffold surfaces with heteroatoms can modify the hydrogen sorption properties of confined metal hydrides in relation to non-functionalized scaffolds (FS). Investigations of nanoconfined LiBH4 and NaAlH4 indicate functionalizing the carbon scaffold surface with nitrogen can shift the activation energy of hydrogen desorption in excess of 20 kJ/mol from the activation energy decrease of e 40 kJ/mol obtained from confinement in non-FS. XPS measurements indicate a significant fraction of the nitrogen contained in the carbon scaffolds is pyridinic, suggesting interactions of the available lone electron pair with the confined hydride and decomposition products strongly influences the hydrogen sorption processes. TPD experiments demonstrate nitrogen-FS can stabilize the release of diborane by ~30 °C, and kinetically stabilize LiBH4 against decomposition to higher temperatures. Increased reorientational activation energies measured for the systems with nitrogen-FS using quasielastic neutron scattering support the observed stabilization of LiBH4 is connected with the surface chemistry of the scaffold. Peak rates of hydrogen release occur at higher temperature from NaAlH4 in nitrogen-FS despite the lower measured activation energy, indicating the existence of a rate-limiting step that may be related to the level of scaffold nitrogen doping and the onset of NaAlH4 melting"--Abstract, page iv.

Advisor(s)

Majzoub, Eric H.
Yamilov, Alexey

Committee Member(s)

Fraundorf, Philip
Holmes, Stephen M.
Medvedeva, Julia E.

Department(s)

Physics

Degree Name

Ph. D. in Physics

Sponsor(s)

University of Missouri Research Board
National Science Foundation (U.S.)
Integrative Graduate Education Research Traineeship
United States. Department of Energy. Office of Basic Energy Sciences

Comments

Presented to the Faculty of the Graduate School of the Missouri University of Science and Technology and the University of Missouri--St. Louis In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in Physics

Funding for this work was provided by the University of Missouri through awards from the Research Board (RB) and Interdisciplinary Intercampus (IDIC) Award Committee.

The authors gratefully acknowledge research support from the Hydrogen Materials Advanced Research Consortium (HyMARC), established as part of the Energy Materials Network under the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, under Award Number DOE-EE0007656.

The authors gratefully acknowledge support from the U.S. Department of Energy, Basic Energy Science, through Grant DE-FG02-ER46256.

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2018

Journal article titles appearing in thesis/dissertation

  • Surface-functionalized nanoporous carbons for kinetically stabilized complex hydrides through Lewis acid-Lewis base chemistry
  • Anomalous H₂ desorption rate of NaAlH₄ confined in nitrogen-doped nanoporous carbon frameworks

Pagination

xii, 174 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2018 Christopher Lee Carr, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11708

Electronic OCLC #

1164805562

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