Confidence Ogbonna Master’s Thesis Defense, Tuesday, December 2, 2025 @ 1:00 pm Central Time

COMMITTEE CHAIR: Dr. Gururaj Neelgund

TITLE: SYNTHESIS, CHARACTERIZATION, AND PHOTOTHERMAL PROPERTIES OF TRANSITION METAL COBALTATE NANOPARTICLES DEPOSITED ON NANOGRAPHENE OXIDE AND NANOGRAPHENE

ABSTRACT: Developing efficient photothermal agents with strong near-infrared (NIR) responsiveness is essential for advancing biomedical applications such as cancer therapy and imaging. In this study, transition metal cobaltate nanoparticles (CuCo2O4, NiCo2O4, ZnCo2O4) were successfully deposited onto nanographene oxide (NGO) and nanographene (NGR) to form NGO-CuCo2O4, NGO-NiCo2O4, NGO-ZnCo2O4, NGR-CuCo2O4, NGR-NiCo2O4, and NGR-ZnCo2O4 composites. Graphene oxide (GO) was synthesized using the modified Hummers and Offeman method, followed by conversion to NGO through probe sonication and reduction to NGR using ethylene diamine. The cobaltate nanoparticles were subsequently deposited via a hydrothermal process. Comprehensive characterization using UV-vis-NIR spectroscopy, ATR-FTIR spectroscopy, XRD, TGA, SEM, and EDS confirmed the successful formation of the composites. Photothermal performance was evaluated by exposing aqueous dispersions of the materials to 980 nm and 808 nm lasers at concentrations of 1 mg/mL, 0.5 mg/mL, and 0.25 mg/mL. The results demonstrated a concentration-dependent increase in temperature, confirming the composites’ effective NIR-responsive photothermal behavior. The findings of this study highlight the potential of these cobaltate-decorated graphene-based materials as promising candidates for photothermal applications in cancer treatment and other biomedical fields.

Keywords: Cobaltate, graphene oxide, graphene, XRD, TGA

Room Location: E.E. O’Banion Science Building, Room 203