Preparation, characterisation and N2O decomposition activity of honeycomb monolith-supported Rh/Ce0.9Pr0.1O2 catalysts

Rh/Ce0.9Pr0.1O2 active phases have been loaded by sequential impregnation into cordierite honeycomb monoliths following the procedure (i) Ce + Pr nitrates impregnation + calcinations and (ii) Rh nitrate impregnation + calcination. The supported catalysts have been characterised by XRD, Raman Spectroscopy, SEM–EDS, TEM–EDS and H2-TPR, and tested for N2O decomposition. Rh is selectively attached to the mixed oxide Ce0.9Pr0.1O2, being 0.2 wt.% the optimum content of Rh. The calcination procedure significantly affects the supported catalyst features. The best catalyst was prepared by flash calcination (introducing the impregnated monolith in a previously heated furnace). Flash calcination yields smaller Rh particles and lowers the temperature for surface Rh–Ce–Pr entities reduction in comparison to ramp calcination, improving both the distribution of active phases on the cordierite substrate and the catalytic activity for N2O decomposition.

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• Flash calcination (impregnated monoliths are introduced in a previously heated furnace) is better than ramp calcination.
• Flash calcination improves the distribution of active phases on the cordierite substrate.
• Flash calcination produces smaller Rh particles and better noble metal–CePr mixed oxide interaction.
• Flash calcination improves the reduction of surface Rh–Ce–Pr entities.
• Flash calcination improves the catalytic activity for N2O decomposition.