Studies on structural and optical properties of cobalt oxide nanoparticles using co-precipitation

This article aimed to study the structural and optical properties of cobalt oxide (Co 3 O 4 ) nanoparticles made using the coprecipitation method. The structural, morphological, and optical properties of as synthesized product were studied using an X-ray diffractometer (XRD), scanning electron microscopy (SEM), and UV - vis absorption spectroscopy, respectively. The XRD pattern of the sample with the refinement revealed the synthesized Co 3 O 4 s ample had a cubic structure with an average of 11. 5 nm- sized crystallites. The SEM of the sample resulted in an agglomerated spherical shape. EDX confirmed the presence of cobalt (Co) and oxygen (O) elements in the sample. The Williamson-Hall method yields anisotropic Co 3 O 4 NPs with an average crystal size consistent with the XRD findings. The optical property has signified that the (direct, indirect) band gap of Co 3 O 4 NPs is between (1.60, 1.58) eV and (2.40, 2.13) eV, indicating (O 2- -> Co 3+ ) and (O 2- -> Co 2+ ) charge transfer processes. Due to their optical properties, Co 3 O 4 nanoparticles may be used for photocatalysis, solar cells, supercapacitors, batteries, and sensing applications.