**5.2. Hydrogenation tests**

**Figure 7** shows the X-ray diffractograms of the composite supports, γ-alumina, Pt/composite, and Pd/composite catalysts. Comparing the results of gamma alumina with those of the composite supports, a close similarity can be seen. This is due to the fact that the inorganic phase used for the preparation of the composite supports is also γ-alumina and that the polymeric phase is amorphous. For all catalysts a peak at 20–39.9° would correspond to the

**Figure 7.** X-ray diffractograms of the composite BTAl (a) and UTAl (b) supports and the corresponding Pd and Pt cata-

**Figure 8** contains the TGA results of the UTAl and BTAl composites, and 1 wt% Pd and Pt

**Figure 8.** TGA traces of the composite supports and the corresponding Pt and Pd catalysts using air as carrier gas.

Inspection of the TGA traces indicates that for both composites the presence of the metal enhances the rate of decomposition of the organic phase.This effect is more important in the case of Pt. This behavior correlates with the nature of these metals that act as combustion

 and Pt0 .

reflections of the (111) planes of Pd0

192 New Advances in Hydrogenation Processes - Fundamentals and Applications

lysts.

composite catalysts.

catalysts in the presence of oxygen.
