Distinct Thermodynamic Properties of Lattice Engineered Clathrate Hydrates for Energy and Environmental Applications

Abstract

A clathrate hydrate is a class of inclusion compound consisting of a host water framework formed by intermolecular hydrogen bonding, with guest molecules such as small gas and low molecular weight organic molecules. In this thesis, I investigated the thermodynamic and kinetics of various binary clathrate hydrates using spectroscopic analysis. The hydrates’ applications are discussed separately in two parts regarding their applications, and each chapter has three chapters dealing with thermodynamic, kinetic, and spectroscopic analyses. Parts 1 and 2 explore clathrate hydrates and their application as functionalized materials for carbon dioxide capture and hydrogen storage, respectively. The first parts of Chapters 2, 3, and 4, focus on clathrate hydrate carbon capture. Chapter 2 reports the unexpected enclathration behavior of CO2 and CH4 molecules using 3,3-dimethyl-1-butanol (DMB) for potential carbon capture applications. Chapter 3 introduces a new hydrate thermodynamic promoter, 2,2 dimethyl-1-propanol (NPA), for CH4, CO2, and N2 molecules and first reports a unique tuning phenomenon in structure I (sI) CO2 hydrates, which can maximize CO2 capture capacity. Chapter 4 also introduces a unique tuning phenomenon in structure II (sII) CO2 hydrates using a novel thermodynamic promoter, epoxycyclopentane (ECP). The second part composed of Chapters 5, 6, and 7 focuses on clathrate hydrate hydrogen storage. Chapters 5 and 6 introduce a novel strategy for hydrogen storage using a natural gas mixture. The theoretically maximum H2 occupancy was experimentally observed in the cages of sII hydrates (double H2 in a small cage, quadruple H2 in a large cage). Chapter 7 first reports the formation of defect sites in the water framework by proton irradiation, to tune the lattice parameters. The double occupation of H2 was observed in the small cages of the THF hydrates at moderate pressure and temperature conditions, following H2 reloading in a lattice elongated THF hydrates.