Effects of the addition of titania on the thermal characterization of alumina-supported palladium

Abstract

The detailed thermal characterization of Pd/TiO2-Al2O3 catalysts under oxygen and hydrogen atmosphere was conducted by means of thermal gravimetric analysis/differential scanning calorimetry (TG/DSC), temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD). A simultaneous TG/DSC measurement revealed that the heat evolved during oxygen adsorption at 25 °C varied slightly with the supports and had a higher value for the smaller palladium crystallite. Hydrogen chemisorption and BET measurements revealed that the coating of Pd/Al2O3 catalysts with titania modified the support character to achieve a high dispersion of palladium. TPR and TPD characterizations of oxidized samples further demonstrated that the coating of Pd/Al2O3 catalysts with titania promoted the reduction and decomposition of PdO into palladium. © 2002 Elsevier Science B.V. All rights reserved.