Influence of CeO2 content on Rh/TiO2 monolithic catalysts for N2O decomposition

In this study the properties of TiO2-CeO2 samples with a cerium oxide content between 0-15 wt.%, prepared by wet impregnation, were analysed by electrophoretic migration technique, XRD, thermogravimetry, N-2 adsorption and mercury intrusion porosimetry. The electrophoretic migration results, showed that the sample with a cerium oxide content around 2 wt.%, present a zero point charge higher than that of the single oxides. Also, a maximum in the BET area, pore volume and XRD intensity of TiO2-anatase peaks was observed for this sample. Taking into account these results, Rh/TiO2-CeO2, monolithic catalysts with different CeO2 content and silicate as binders, were prepared and tested in N2O decomposition reaction. A maximum in N2O conversion was achieved for catalysts with a CeO2 content around 2 wt.% with respect to TiO2. The monolithic catalysts behaviour was related with the properties of TiO2-CeO2 powder samples and it is suggested that the formation of an new Ti-O-Ce phase could be responsible for the different properties of this system.