Date of Award
Fall 12-8-2025
Document Type
Thesis
Publication Status
Version of Record
Submission Date
December 2025
Department
Biomedical Engineering
College Granting Degree
Engineering and Computer Science
Department Granting Degree
Biomedical Engineering
Degree Name
Master of Science (MS)
Thesis/Dissertation Advisor [Chair]
Vivian Merk
Abstract
This study presents a detailed exploration of the synthesis, morphological tuning, and physicochemical characterization of nickel nanoparticles (NiNPs) engineered for catalytic applications in aqueous environments. Using a modified polyol method adapted from Couto et al., nanoparticles were synthesized under controlled thermal and chemical conditions with nickel chloride hexahydrate, polyvinylpyrrolidone (PVP), and sodium borohydride in ethylene glycol according to a modified version of this synthesis protocol.1 The reaction temperature and reactivity of the reducing agent were found to significantly influence particle size. Reaction temperatures were varied between 120° C and 170° C, resulting in nanoparticle sizes between 23 ± 7 nm and 13 ± 4 nm. Potent NaBH₄ enabled rapid burst nucleation, yielding uniform NiNPs in < 25 nm size range. Post-synthesis processing included rigorous washing and sonication to minimize residual contaminants and enhance colloidal stability. The morphological and chemical characterization of NiNPs was conducted using transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potentials, energy-dispersive X-ray spectroscopy (EDS), electron energy loss spectroscopy (EELS), alternating gradient magnetometry (AGM), and high-angle annular dark field (HAADF) scanning TEM imaging. DLS and zeta potential measurements confirmed the role of surface charge in providing nanoparticle stability2. STEM-EELS mappings was used to quantify the level of surface oxidation occurring at various reaction temperatures, which can affect the catalytic activity of NiNPs. It was found that surface oxidation increased with the reaction temperature. AGM was used to obtain hysteresis curve measurements to quantify the magnetic properties of the NiNPs. The saturation magnetization was found to increase with the reaction temperature. The findings provide a systematic foundation for engineering nanoparticle synthesis and surface chemistry towards CO2 remediation in freshwater and saltwater, an environmentally relevant aqueous-phase application. The work highlights the importance of surfactant selection and reaction temperature as controllable levers for engineering size, dispersion, stability, and magnetic recoverability — critical factors for future integration into aqueous-phase systems and nanomaterial-based environmental technologies.
Recommended Citation
Saintilme, Gladel, "CONTROLLING THE SIZE AND SURFACE CHEMISTRY OF NICKEL NANOPARTICLES VIA A MODIFIED POLYOL METHOD" (2025). Electronic Theses and Dissertations. 222.
https://digitalcommons.fau.edu/etd_general/222