Magnetic, infrared and catalytic studies of PtFe/SiO2 catalysts

Abstract

Magnetic measurements on the PtFe/SiO₂ system revealed a completely reduced form of iron in platinum–iron clusters at iron concentrations of up to 40 atom %, whereas at 70 atom % iron, part of the iron could not be reduced. These results are in good agreement with an earlier Mössbauer study in our laboratory.

The infrared spectra of CO adsorbed on PtFe/SiO₂ were measured and an ≈ 100 cm^–1 shift was found in the lower characteristic band, which is assigned to strongly adsorbed Pt + CO species.

Catalytic reactions of propene have been carried out on Pt/SiO₂ and 70 atom % iron containing catalyst. Three reactions, hydrogenation, dimerization to produce benzene and cracking take place. On iron rich catalysts the selectivity for benzene formation and for hydrogenation is high, while on platinum rich catalysts methane formation is the main reaction.