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Tunability of Gas Adsorption Enthalpies in Carbonaceous Materials for Energy-Related Applications


Quine, Cullen Mackenzie (2023) Tunability of Gas Adsorption Enthalpies in Carbonaceous Materials for Energy-Related Applications. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/r5ad-1j85.


Carbonaceous materials provide a porous, high surface area framework for the adsorption of gases through physisorption. Physisorption operates through van der Waals forces, resulting in highly reversible, densified gas storage. The density of adsorbed gas species approaches the bulk liquid density, providing a method to increase the volumetric energy density of hydrogen and natural gas at conditions where the adsorbate is a non-liquid in the bulk phase. This dissertation explores the tunability of the strength of gas adsorption to surfaces of carbon adsorbents, known as the enthalpy of adsorption. Two methods are studied: modification of the surface atomic composition and microstructural changes to the carbon porosity. Applications are considered for both energy storage and carbon capture applications.

The first chapter presents a brief overview of the energy storage field, with emphasis on non-conventional methods to store gases efficiently. Chapter 2 provides the thermodynamic and statistical mechanical derivations used throughout this work, and the assumptions that go into the models used to analyze adsorption data. Chapter 3 reports work on a copper-modified commercial carbon MSC-30 for hydrogen storage, which exhibits an activated dissociative chemisorption desorption feature around ambient temperature. Chapter 4 presents the densification of a novel architected carbon structure, zeolite-templated carbon, for adsorbed natural gas storage. Through the pelletization process, the pore morphology of the underlying adsorbent framework is compressed, resulting in increased adsorption enthalpies with applied pelletization pressure. Chapter 5 focuses on the tunability of pore structure through potassium hydroxide activation, and the resulting adsorption properties pertinent to carbon dioxide capture from a simulated flue-gas stream. The last chapter provides insight into the work as a whole and identifies areas of future work that would improve the fundamental understanding and broader impact of adsorbent materials.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:adsorption; physisorption; chemisorption; enthalpy; isotherms; pore structure modifications; carbon adsorbents; hydrogen storage; methane storage; energy storage; thermodynamic adsorption;
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Materials Science
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Fultz, Brent T. (advisor)
  • Ahn, Channing C. (co-advisor)
Thesis Committee:
  • Fultz, Brent T.
  • Schwab, Keith C. (chair)
  • Wang, Zhen-Gang
  • Stadie, Nicholas
  • Ahn, Channing C.
Defense Date:15 May 2023
Funding AgencyGrant Number
Office of Energy Efficiency and Renewable Energy (EERE)DE-EE0007048
Office of Energy Efficiency and Renewable Energy (EERE)DE-EE0008815
Resnick Sustainability InstituteUNSPECIFIED
Record Number:CaltechTHESIS:05292023-054311609
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for Ch. 3
Quine, Cullen Mackenzie0000000273010969
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15222
Deposited By: Cullen Quine
Deposited On:03 Jun 2023 01:46
Last Modified:04 Dec 2023 17:49

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