Combined TDPAC and EXAFS study of InPt/FER catalysts

Time Differential Perturbed Angular Correlation (TDPAC) experiments using ( 111) In as probe were performed in order to determine the nature of In-site s in In-ferrierite (In/FER), before and after the incorporation of Pt throu gh the hyperfine interaction between the nuclear quadrupole moment of the p robe's nucleus and the extranuclear electric field gradient (EFG). Extended X-ray Absorption Fine Structure (EXAFS) measurements were performed to mea sure the absorbance above the Pt's LIII absorption edge in the transmission mode in order to determine the local environment of Pt atoms in Pt/EER and InPt/FER catalysts. TDPAC spectra of In-111 in In/FER and InPt/FER taken at 500 degrees C in ai r indicated that there are no changes in the indium surroundings after the incorporation of Pt. Three sites were found for indium in both samples. Two of them correspond to the two sites of indium in In2O3 and the third one i s attributed to In in exchange sites of the zeolites. Their population, qua drupole frequencies and asymmetry parameters didn't change with the incorpo ration of Pt. EXAFS experiments showed similar near neighborhood Pt-O dista nces and Pt coordination number in Pt/FER and InPt/FER samples. There is no evidence of the presence of any In-Pt bimetallic entity in InPt/FER cataly st.