Mesoporous silica-pillared clays supported nanosized Co3O4-CeO2 for catalytic combustion of toluene

Mesoporous silica-pillared clay (SPC) was synthesized by a soft template method. Compared with the raw montmorillonite (MMT), the basal spacing of SPC increased from 0.96 to 2.61 nm, the specific surface area increased from 30 to 453 m2/g, and the thermal stability was also improved, all of which could reduce the mass transfer resistance and improve the adsorption capacity of toluene. SPC supported Co3O4 and rare earth (Y, La, Ce, Pr and Nd) nano-composite catalysts were prepared by a deposition-precipitation method. Among them, 10% Co-5% Ce/SPC displayed the highest catalytic combustion activity, and the reaction temperature for toluene combustion was about 200 °C (98% conversion). This catalyst displayed good durability, and conversion of toluene dropped slightly from 96% to 90% in 1000 h continuous reaction at 190 °C. Co3O4 and CeO2 had particle sizes of 5–8 nm and were dispersed homogeneously on the surface of SPC. Introduction of CeO2 enhanced oxygen storage/transport capacity, and improved the dispersion of Co3O4 on SPC. The interaction of Co3O4-CeO2 and SPC, the co-existence of Co2+/Co3+ and the higher concentration of Ce3+ ions on the catalyst surface contribute to the high catalytic oxidative activity of 10% Co-5% Ce/SPC for toluene combustion.