Catalytic combustion of volatile organic compounds (VOCs) over structured Co₃O₄ nano-flowers on silicalite-1/SiC foam catalysts

This work presents a simple method for the preparation of structured Co₃O₄ supported on silicalite-1/SiC foam catalyst (i.e., Co@S1/SiC), and its application to catalytic combustion of volatile organic compounds (VOCs, isopropanol as the model compound). The growth mechanism of Co₃O₄ on silicalite-1/SiC catalysts were systematically studied as a function of synthesis time based on comprehensive characterization using N₂ adsorption-desorption analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), H₂ temperature programmed reduction (H₂-TPR) and X-ray photoelectron spectra (XPS). It was found that Co₂SiO₄ nano-sheets were formed within/on silicalite-1 coating at the initial stage of synthesis, which was further transformed into flower-like Co₃O₄ nano crystals on the surface of silicalite-1/SiC. The developed structured catalyst, especially the one prepared by the 40 h synthesis, i.e., Co@S1/SiC-40 h, combined high oxygen mobility, Co³⁺/Co²⁺ redox couple and improved adsorbed oxygen species, and exhibited excellent performance in complete thermocatalytic combustion of isopropanol.