Novel, efficient hollow zeolitically microcapsulized noble metal catalysts

Hollow zeolitically microcapsulized (HZMC) catalysts with encapsulated noble metal nanoparticles, such as Pt and Ag, have been successfully fabricated through a hydrothermal transformation process. A series of catalytic oxidation reactions of alcohols were performed both on HZMC catalysts and on commercial catalysts, such as Pt/SiO2 and Pt/Al2O3. The HZMC catalysts exhibit good reactant selectivity due to the existence of a zeolitic shell. More interestingly, the HZMC catalysts retained most of their reactivity even in the presence of a significant amount of poison contaminants (>5 vol%), whereas the reactivity on commercial catalysts was quickly quenched under the same conditions. Furthermore, the HZMC catalysts could be recycled for at least 6 runs without losing their activity, whereas the commercial catalysts deactivated rapidly with the recycling. The unique reactant-selectivity, poison-resistance, and reusability of the HZMC catalysts demonstrate that the strategy of zeolitic encapsulation for noble metal catalysts is effective and applicable in practice.