Note on a dynamic study of a complete catalytic process by X-ray absorption spectroscopy in dispersive mode: application to IrCu/Al2O3 catalysts

In this paper in situ X-ray absorption in the dispersive mode on Ir Cu/γ-alumina catalysts during several oxidation-reduction cycles is described. Moreover, catalytic reactions as hydrogenolysis of methylcyclopentane and isomerization of labelled hexanes were performed as tests of the final reduced forms of the catalysts. Only the raw EXAFS data are reported here. But, even at this stage of our investigations, it is clear that the time resolved technique we used gives a large enough signal-to-noise ratio and energy band pass to describe various catalytic processes in full detail. Such new possibilities of looking at structural and electronic evolutions will undoubtly provide interesting insights in the kinetic aspects of a catalytic reaction. With Irx Cuy catalysts it has been observed that (i) both Ir and Cu are fully reduced at 150°C under H2, flow, (ii) the Ir Cu catalyst reduced at 150°C keeps the intrinsic properties of iridium, and (iii) after reduction at 300°C the properties of iridium seem to be lost. From a carbon-13 experiment we can suggest an Ir Cu interaction.