Preparation and characterization of a novel washcoat material and supported Pd catalysts

Abstract

A nanosized Ce0.5Mn0.5O1.5 powder was successfully synthesized by macromolecule surfactant modified method and then it was used as the cordierite honeycomb washcoat of VOCs combustion catalysts. The effect of Ce-Mn-O powder with different Ce/Mn molar ratio on the catalytic activity and the cohesive ability of washcoat on the cordierite honeycomb substrate was also investigated. The structure and catalytic properties of Ce0.5Mn0.5O1.5 washcoat were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), differential thermal analysis and thermo-gravimetric analysis (TG/DTA), and N2 adsorption and desorption techniques. The results indicated that the Ce0.5Mn0.5O1.5 powder belongs to a novel washcoat with the advantages of strong cohesiveness, high surface area and without agglomeration even after 1000°C calcination. The total oxidation temperature for toluene, acetone and ethyl acetate over the 0.1 wt % Pd/Ce0.5Mn0.5O1.5/cordierite honeycomb catalysts was at 200, 220 and 220°C, respectively. Compaired with the catalysts without Ce0.5Mn0.5O1.5 washcoat, the catalyst with Ce0.5Mn0.5O1.5 as washcoat on the cordierite honeycomb could improve the dispersion of PdO and shows a good catalytic activity for toluene, acetone and ethyl acetate.