Date of Graduation

12-2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Chemistry (PhD)

Degree Level

Graduate

Department

Chemistry & Biochemistry

Advisor/Mentor

Coridan, Robert H.

Committee Member

Chen, Jingyi

Second Committee Member

Stenken, Julie A.

Third Committee Member

Kilyanek, Stefan M.

Keywords

Atomic Layer Deposition; Catalysis; Hierarchically-structured materials; Non-Thermal Plasma; Thin-Films; X-ray reflection

Abstract

The reduction of CO2 into products for either the storage of renewable electricity or to act as a source of renewable feedstock for industry, is not economically feasible given the current costs of renewable energy. Significant amounts of work have gone into attempting to optimize both electrochemical and nonthermal plasma-based CO2 reduction systems in an attempt to reduce side reactions and improve energy efficiency in order to meet cost feasibility targets. These techniques can also be adapted for In-Situ Resource Utilization (ISRU) contexts, which are far less sensitive to the cost of renewable energy yet have more strenuous demands on operating conditions and resource use. In this thesis, we will report on the use of a modified solvent system for electrochemical CO2 reduction in low temperature environments. We report that the use of the organic-aqueous solvent system reduces the current towards hydrogen evolution when used under ambient conditions. This allows an unoptimized electrochemical cell to function at a reduced temperature. We also report the design of a non-thermal plasma catalyst by using atomic layer deposition (ALD) to deposit metal oxide plasma CO2 reduction catalysts onto a support. The use of ALD enables the regularization of the surface area, morphology, and permittivity of different metal oxide plasma catalysts. This allows us to compare the activity of different catalysts without the convoluting effects variations in surface morphology, packing density and local electric field enhancement that would normally result from varying synthesis methods. We report that the ALD catalysts are robust to plasma exposure and can be used for several hours in without significant loss of activity. We also observe the morphology and thickness of the ALD catalysts before and after exposure to low pressure glow discharge conditions for several hours. We found the catalysts were not etched by oxygen ions or any other gas phase species, and only observed minimal surface material redistribution.

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