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In this work, polyaniline (PANI)-rhodium composites have been obtained for the first time. Their preparation procedure has involved reduction of Rh 31 ions in RhCl 3 aqueous solutions with NaBH 4 in the presence of PANI. Using UV-vis spectroscopy, it has been found that the reduction process is fast. X-ray diffraction and Rh3d XPS studies have confirmed that metallic rhodium is incorporated into PANI matrix. SEM and TEM investigations allowed to establish that the sizes of Rh crystallites formed depend on the amount of metal in the composite as well as on the preparation conditions. It has been demonstrated that the composites containing Rh nanoparticles whose size is predominantly below 10 nm can be obtained. IR spectroscopy has proved that PANI chain is protonated in the Rh 31 reduction process. Catalytic properties of PANI-Rh composites have been investigated using isopropyl alcohol conversion as the test reaction. It has been found that the composites containing Rh nanoparticles show high redox activity. Catalytic activity of the composites in which larger, agglomerated metal particles have been present is about three times lower.

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Composites of polyaniline (PANI) or polypyrrole (PPy) doped with chloride ions and Pt or Rh particles were prepared by chemical reduction of metal ions conducted in the presence of the polymers. Based on X-ray diffraction studies it was established that the composites contained metal nanoparticles (5-9 in size). However, according to SEM investigations metal particles were agglomerated (40 nm-1.1 lm in size). Redox activity of the composites in the catalytic isopropyl alcohol conversion was ca. ten times higher than the acid-base one. Pt dispersed in polymer matrices showed higher catalytic activity than Rh. PPy doped with chloride ions had a promoting effect on the activity of Pt catalysts.

Oxidative dehydrogenation of cyclohexane could be very promising and complementary test reaction to evaluation of redox properties of the catalyst surface, which are very important in the selection of materials for neutralisation of NO x . The process is autothermic and it runs in significantly lower temperatures than conventional dehydrogenation.