The effects of the Pt-Sn/Al2O3 catalysts preparation methods on the chemisorption of carbon monoxide

The paper reports on the effect of the synthetic procedure of the Sn/AI2O3 catalyst on the type of the surface platinum centres. The catalysts were obtained with the method of incipient wetness introducing either the first tin followed by platinum after drying (the first series) or platinum and then tin (the second series) or two components simultaneously (the third series). The catalysts performance was studied by CO sorption and the type and the character of the chemisorption centres was determined by the FT-IR method. The results indicated the formation of different platinum centres: Pt^o, Pt^delta+ (δ+≤ 1), Pt^m+ (2 ≥ m > 1) depending on the sequence of the introduction of the active components.