Synthesis and Characterization of Calcium Oxide Nanoparticles (CaO-NPs) from Waste Oyster Shells

Abstract

This study describes a method for synthesizing calcium oxide nanoparticles (CaO-NPs) from oyster shells, a waste material. The characterization of the synthesized CaO-NPs was conducted using X-ray diffraction (XRD), UV-visible spectroscopy, Raman spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and dynamic light scattering (DLS). The XRD analysis confirmed the formation of CaO-NPs with an average crystal size of 57.18 nm. The UV-visible spectrum revealed maximum absorption at 206 nm, indicating absorption in the ultraviolet region. The band gap energy of the CaO-NPs, determined using the Tauc plot, was found to be 5.90 eV and 5.93 eV for direct allowed and indirect forbidden transitions, respectively. Raman and FTIR spectroscopy analyses provided further confirmation of the presence of CaO-NPs. Finally, DLS measurements revealed an average hydrodynamic diameter of 54.85 nm for the CaO-NPs, classifying them as macroporous. The macroporous structure suggests potential photocatalytic properties for the synthesized CaO-NPs.