The aim of the present work is to synthesize a zeolite-based catalyst with a hollow morphology and highly dispersed metal nanoparticles (NPs) encapsulated inside the zeolite micropores. For this purpose, we have studied a treatment using tetraalkylammonium (TAA) bromides for the selective removal of a large Pt particle from the outer surface of a hollow Beta zeolite. TEM analysis reveals that we succeeded in the synthesis of a hollow beta zeolite single crystal with encapsulated particles, with a high dispersion of 50-60 %. The molecular-sieve-type mechanism of the obtained catalysts was evaluated in the model reaction of toluene and mesitylene catalytic hydrogenation. Thanks to the high dispersion. a 10-fold activity enhancement has been obtained with respect to hollow beta zeolites with encapsulated NPs recently described in the literature.
Keywords: heterogenous catalysis; metal nanoparticles; selective hydrogenation; size selectivity; zeolites.
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