Defense Date
2026
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Chemistry
First Advisor
Dr. Katharine M. Tibbetts
Abstract
Electrochemical conversion of CO2 into industrially valuable chemicals such as ethylene and ethanol represent a critical strategy for reducing atmospheric CO2 levels, storing renewable electricity in chemical form, and minimizing reliance on virgin fossil resources for chemical production. However, achieving high product selectivity in CO2 electrochemical reduction (CO2 ECR) remains a significant challenge, as the simultaneous transfer of multiple carbon atoms and protons can produce a wide variety of products. Consequently, the development of catalysts that enable selective CO2 ECR reduction toward multicarbon (C2+) products is essential for realizing efficient and economically viable CO2 utilization technologies. Reactive laser ablation in liquid (RLAL) provides a green and highly controllable route to synthesize layered silicate nanomaterials with tunable properties. Using femtosecond (fs) or picosecond (ps) laser pulses in aqueous solutions, RLAL enables precise control over particle size, morphology, crystallinity, and metal oxidation state, offering a versatile platform for designing functional nanomaterials for catalytic and other advanced applications. In this work aluminosilicate nanominerals and Cu-phyllosilicate catalysts were efficiently synthesized via RLAL, with composition, morphology, and crystallinity strongly governed by precursor solution chemistry and laser parameters. NH3-based solutions produced amorphous, tube- or fiber-like aluminosilicates, whereas KOH-based solutions yielded crystalline, quasi- spherical particles comprising multiple aluminosilicate and potassium aluminosilicate phases,
achieving high aluminum incorporation at pH ≥ 6. Cu-phyllosilicates displayed tunable structure and surface chemistry: KOH-derived CuPS contained crystalline Cu2O embedded in an amorphous silicate matrix, with femtosecond-synthesized samples exhibiting superior CO2-to-ethylene selectivity (84% vs 29% for ps-laser at −1.1 V vs RHE) due to an increased density of active Cu+ sites. In contrast, NH3-derived CuPS formed amorphous, needle-like frameworks with elevated surface Cu content (Cu–NH3–ps: 15.4 at.% Cu; 48% Cu+), while HRTEM confirmed the absence of Cu2O phases, attributed to oxygen defects. These findings establish RLAL as a green, ambient- condition platform for precise control over nanomaterial composition, morphology, and metal oxidation state, enabling the rational design of highly selective and durable catalysts for CO2 electroreduction and other advanced applications.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-8-2026