Preparation and characterization of mixed metal oxide ZnCo₂O₄ spinel coated ACF for environmental remediation

This paper reports a facile, economical and surfactant free synthesis of three-dimensional hierarchical ZnCo₂O₄ microspheres with water as medium. The scanning electron microscopic images demonstrated the evolution of hierarchical structure from solid sphere. Moreover, three dimensional microcubes were grown on ACF under the same reaction conditions. Thermal analysis of the precursor microspheres was conducted to determine the annealing temperature. N₂ adsorption-desorption experiments provided evidence for the mesoporous nature of the ZnCo₂O₄ powder and microporous nature of the ZnCo₂O₄/fiber. The surface area of ZnCo₂O₄ developed at 12h and 24 h was determined to be 32.73 and 24.91 m² g⁻¹ respectively whereas that for ZnCo₂O₄ /ACF was 446 m² g⁻¹. Chemical composition as revealed from the XPS results and the XRD pattern confirmed the growth of ZnCo₂O₄ on ACF. Molecular vibrations of the synthesized materials were studied using Raman spectroscopy. The photocatalytic performance of the developed materials was determined in terms of reaction rate constant. It was found that ZnCo₂O₄ microcubes on ACF exhibited higher reaction rate constant of 1.17 × 10⁻² min⁻¹ and 1.46 × 10⁻² min⁻¹ respectively for Malathion and 2, 4—dichlorophenol degradation. (paper)