Influence of textural parameters on the catalytic behavior for CO oxidation over ordered mesoporous Co3O4

Abstract

Ordered mesoporous Co3O4 has been synthesized by nanocasting from three-dimensional cubic KIT-6 template. The cobalt precursor is introduced into the silica pores by the “bi-solvent” method. The structure and textural characteristics are investigated by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, nitrogen sorption at 77K. By changing the hydrothermal temperature of the KIT-6 template, two kinds of Co3O4 replicas with different mesostructured symmetries are obtained. Mesoporous Co3O4 oxides prepared from KIT-6 aged at low temperature have uncoupled sub-frameworks while mesoporous Co3O4 oxides prepared from KIT-6 aged at high temperature possess coupled sub-frameworks. CO oxidation is carried out as a model reaction to evaluate the catalytic activity. Co3O4 replicas with uncoupled sub-frameworks which possess higher surface area and more open pore system exhibit better performance than Co3O4 replicas with coupled sub-frameworks. The light-off temperature of CO oxidation reaches as low as 68°C with a space velocity of 120,000 mL h−1 gcat−1 over the uncoupled Co3O4 replica. Calcination temperature of the cobalt precursor only has negligible or slight impact on the catalytic activity.