Date of Award

Spring 5-18-2026

Document Type

Restricted Thesis

Degree Name

Bachelor of Arts (BA)

Department

Chemistry

First Advisor

Juan Navea

Abstract

Interfaces play a central role in chemistry, governing processes that range from heterogeneous catalysis and energy transfer to atmospheric reactivity and environmental cycling. Surface phenomena are particularly important in systems where molecular interactions at solid-gas or solid-liquid boundaries control chemical transformation, transport, and reactivity. This thesis explores two distinct yet interconnected areas of interfacial chemistry: the dissolution of iron from photoactive combustion aerosol analogues during atmospheric processing and the heterogeneous oxidation of adsorbed hydrocarbons by non-thermal plasmas. The first section focuses on the dissolution and speciation of iron from combustion aerosol analogues under acidic atmospheric conditions. Atmospheric combustion particles represent an important source of bioavailable iron to marine environments, where iron availability can regulate phytoplankton productivity and influence global carbon cycling. To isolate the role of surface composition and mineralogy, fully characterized TiO2-anatase nanoparticles containing controlled amounts of iron and copper, either doped or grafted, were used as model combustion particles. The effects of light exposure, copper content, and surface structure on iron dissolution kinetics and speciation were evaluated, highlighting the importance of photocatalytic and interfacial processes in controlling iron mobility during atmospheric aging. The second section investigates the oxidation of surface-bound hydrocarbons by ground-state atomic oxygen, O(3P), generated through radio-frequency non-thermal plasmas. Non-thermal plasmas provide a promising low-temperature approach for transforming petroleum-derived compounds while minimizing side reactions commonly associated with thermal oxidation. Because volatile and semi-volatile compounds readily partition into the plasma phase under low-pressure conditions, adsorption onto surfaces provides a pathway to stabilize these compounds and promote heterogeneous oxidation. Using a custom-designed reaction chamber coupled with in situ vibrational spectroscopy, the heterogeneous oxidation kinetics of adsorbed 1-hexene and cyclohexane on alumina surfaces were examined. Complementary theoretical geometry optimizations were used to evaluate adsorption configurations and their influence on reaction pathways. The results demonstrate that adsorption geometry strongly influences reactivity and selectivity, with adsorption of alkenes significantly hindering access of O(3P) to carbon–carbon double bonds.

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