Moessbauer Spectroscopy: an elegant tool for the active sites identification and quantification in Pt-Sn-In based naphta reforming catalysts

摘要

Trimetallic PtSnln/Al_2O_3-Cl catalysts have been synthesized by successive impregnations (SI) of metals and characterized by ~(119)Sn Moessbauer Spectroscopy (MS). Various Sn-species have been identified thanks to the use of a Δ (Quadrupole Splitting) - δ (Isomer shift) diagram.~(119)Sn MS results show that addition of different amounts of In (0.11 to 0.55 wt.%) lead to the formation of Pt_xSn(O) oxo-metallic phases. As the In loading increases these Pt_xSn(O) oxo-metallic phases are richer in Pt. The preferential formation of a given Sn phase in these catalysts is directly related to the preparation method.