CHARACTERIZATION BY IN-SITU EXAFS SPECTROSCOPY OF PT AL2O3 AND PTRE/AL2O3 CATALYSTS UNDER REACTION CONDITIONS/

The effects of the catalytic reforming of n-heptane on the metallic ph ase of Pt/Al2O3 and PtRe/Al2O3 catalysis have been studied by EXAFS sp ectroscopy. In both catalysts, a new platinum carbon bond is formed du ring the catalytic reaction, coming from the deposition of carbonaceou s residues over the metallic phase. However, in the case of the PtRe/A l2O3 catalyst this bond is formed only at lower temperature and is acc ompanied by important changes in the structure of the metallic particl es. All these results are consistent with the existence of a PtRe inte rmetallic phase in the bimetallic catalyst, which intercepts more effi ciently the coke precursors.