Ordered mesoporous CrCeOx catalyst prepared by hard template for toluene and formaldehyde combustion

Abstract

The meso-Cr-Ce catalysts with different proportions of chromium and cerium were prepared using three-dimensional ordered mesoporous silica (KIT-6) as hard template by vacuum assisted impregnation method. The physicochemical properties of the catalysts were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), nitrogen adsorption-desorption (BET), transmission electron microscopy (TEM), Scanning electron microscopy (SEM) and temperature programmed reduction (TPR) techniques. The oxidation removal performance of toluene and formaldehyde was evaluated. The results show that all catalysts have better catalytic oxidation activity than the bulk counterpart. The meso-Cr-Ce-1 catalyst of same Cr/Ce molar ratio was larger in surface area (up to 186 m²/g) and could be reduced at lower temperatures, and exhibited the highest catalytic oxidation performance. At 30,000 h⁻¹ of space velocity and 1000 ppm of VOC, toluene and formaldehyde conversions reached 90 % at 240 and 160 °C, respectively, and the apparent activation energies were 64.1 and 37.2 kJ/mol. The excellent performance of the catalyst is associated with its well-developed mesoporous structure, high specific surface area, good low temperature reducibility and dispersion and synergistic effect of active components.