Co3O4 nanocrystals on graphene oxide as a synergistic catalyst for degradation of Orange II in water by advanced oxidation technology based on sulfate radicals

Abstract Graphene oxide and cobalt oxide nanocomposites (Co 3 O 4 /GO) are fabricated in situ as heterogeneous catalysts by the decomposition of cobalt nitrate through heat and crystal growth of Co 3 O 4 on the surface of GO sheets in 1-hexanol solvent. The Co 3 O 4 /GO catalyst is characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). Results show that the Co 3 O 4 /GO catalysts are large GO sheets decorated homogenously with well-dispersed Co 3 O 4 nanoparticles. Although Co 3 O 4 or GO alone exhibit little catalytic activity, their hybrid (Co 3 O 4 /GO) exhibits an unexpectedly high catalytic activity in the degradation of Orange II in water by advanced oxidation technology based on sulfate radicals, and 100% decomposition can be achieved in 6 min. These phenomena suggest a synergistic catalytic activity of Co 3 O 4 and GO in the hybrid.