Structural and optical properties of Co 3 O 4 nanoparticles prepared by sol-gel technique for photocatalytic application

Abstract

Co 3 O 4 (Cobalt Oxide) nanoparticles (NPs) were synthesized via sol-gel method by taking cobalt acetate (Co(OAC)) as a precursor material at four different concentrations like 0.06, 0.07, 0.08,and 0.09 M. The obtained Co 3 O 4 was used as the photocatalyst for the degradation of methylene blue dye. The phase pure cubic spinel cobalt oxide formation was confirmed by powder X-ray diffraction (PXRD). The surface morphology and elemental analysis were studied by FESEM and EDAX. The SEM image showed that the particle size ranged from 200 nm to 1μm with respect to the concentration of the cobalt acetate precursor. Surface defects, vibrational and rotational modes of Co 3 O 4 was determined by Raman studies. The functional groups of the cubic spinel Co 3 O 4 were determined by the Fourier Transform Infrared Spectroscopic (FTIR) analysis. The optical behavior of the prepared material was investigated by UV-Vis and PL spectroscopic studies. The band gap of Co 3 O 4 varied as1.29 eV and 3.34 eV for Co 3 O 4 -006, 1.39 eV and 3.53 eV for Co 3 O 4 -007, 1.59 eV and 3.58 eV for Co 3 O 4 -008 and 1.63 eV and 3.65 eV for Co 3 O 4 -009 is due to the quantum confinement effect. The Co 3 O 4 -006 showed 93.8% degradation of methylene blue dye under visible light irradiation.