STUDY OF THE EFFECT OF Ti ON THE NATURE OF SURFACE ADSORPTION SITES IN Pt-Ti-Al_2O_3 CATALYST
Yang Xiyao, Ren Shaoling and Pang Li(Department of Chemistry, Beijing University)
The effect of titania additives upon the nature of surface adsorption sites in a series of Pt-Ti-Al2O3 catalysts with various titanium loading (0.06-1.00 wt%),was investigated by using temperature programmed reduction, temperature programmed desorption and H2-O2 titration techniques. The results show that the number of activated adsorption sites is increased, while the number of non-activated adsorption sites is diminished. However, the total number of adsorption sites remains unchanged. Besides an enhancing and improving effect of Ti on the thermal stability of Pt-Ti-AlzO3 catalyst in hydrogen stream was also observed. The phenomena observed are suggested as a result of an ensemble size effect or structural effect.