Green synthesis of Co3O4 nanoparticles using Euphorbia heterophylla L. leaves extract: characterization and photocatalytic activity

In this research, Co3O4 NPs were prepared by green synthesis method using Euphorbia heterophylla L. leaves extract (ELE). ELE contains secondary metabolite compounds like alkaloid, as weak base source, and saponin, as capping agent, in the synthesis of Co3O4 nanoparticles. The Fourier-Transform Infrared (FTIR) spectrum of ELE depicted some peaks at 3245, 1610 and 1071 cm(-1) which represented hydroxyl group, carbonyl group (C=O) and C-N group, respectively. Co3O4 NPs were characterized by FTIR Spectrometry, UV-Vis Spectroscopy, Particle Size Analyser (PSA), X-Ray Diffraction (XRD) and UV-Vis DRS. The FT-IR results showed the presence of Co (II)-O bond and Co (III)-O bond at the wavenumber of 574 and 699 cm(-1), respectively. UV-Vis characterization spectroscopy indicated the typical peak of Co3O4 NPs found at the range wavelength of 200-350 nm and 380-600. The particle size of Co3O4 NPs was 69.75 nm confirmed by Particle Size Analyser. XRD characterization showed that Co3O4 NPs had diffraction peaks at 31.1953 degrees; 38.5401 degrees; 44.8076 degrees; 50.2027 degrees; 59.2743 degrees and 65.1419 degrees. The band gap energy of Co3O4 NPs was 1.53 eV confirmed by UV-Vis DRS. TEM image showed that morphology of Co3O4 NPs was spherical shaped with the particle size of similar to 17 nm. Co3O4 NPs had a photocatalytic activity in the degradation of methylene blue about 63.105% for 3 hours.