Graduation Year

2020

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Chemistry

Major Professor

Brian Space, Ph.D.

Committee Member

Shengqian Ma, Ph.D.

Committee Member

H. Lee Woodcock, Ph.D.

Committee Member

Babu Joseph, Ph.D.

Keywords

metal-organic frameworks, gas sorption, molecular simulation

Abstract

Metal-organic frameworks are a diverse group of crystalline materials consisting of metal ionscoordinated to organic ligands. Their characteristic high porosity, large surface area along with tunable pore structures and chemical functionalities make them an exceptional candidate for H2 storage applications. Computational studies of H2 sorption in metal-organic frameworks aid in producing molecular-level insights which can facilitate the design of structures with improved performance. In this work, various MOFs were investigated using grand canonical Monte Carlo simulations.

Addressed first are two MOFs with rht topologies which consist of two chemically distinct Cu2+ ions coordinated to triisophthalate ligands. Through electronic structure calculations and classical simulations it was revealed that minor modifications to the ligand that are not in close proximity to the open metal sites led to drastic differences in the charge distribution within the copper paddlewheel and affect which metal site would be preferred for sorption. Furthermore, it was found that minor modifications to the ligand have the potential to create additional sorption sites which are not present in prototypical structures and can also give rise to enhanced heat of sorption for H2.

The final chapter focuses on a MOF system with a highly asymmetrical structure whereby the metal ions are coordinated to two types of ligand in a distorted octahedral fashion. This chapter provides a comparison of two different metal analogues (Mg2+ and Co2+) , highlighting their interchangeability and also providing insights into favored sorption sites in this type of system.

Included in

Chemistry Commons

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