Self-assembly of hollow spherical nanocatalysts with encapsulated Pt NPs and the effect of Ce-dipping on catalytic activity

This article reports a facile and controllable one-step method to construct Pt@hollow mesoporous SiO2 (Pt@HMSiO2) nanoparticles (NPs). To enhance the catalytic activity, cerium species were impregnated into Pt@HMSiO2 NPs, fabricating highly reactive Pt–CeO2@HMSiO2 NPs. To verify the successful synthesis of the Pt@HMSiO2 and Pt–CeO2@HMSiO2 NPs, and study the influence of CeO2 species on the catalytic performance, the as-prepared NPs were characterized by several techniques, including SEM, TEM, EDX, FTIR, XRD, BET and UV-vis analyses. In this work, the reduction of 4-NP was employed as a model reaction to test the catalytic performance. Compared to Pt@HMSiO2, the Pt–CeO2@HMSiO2 NPs show higher catalytic activity, because of the co-catalysis of CeO2 NPs. However, the excess amount of CeO2 NPs would lead to a lower catalytic activity, due to the blocking of the catalyst pore. In addition, the Pt–CeO2@HMSiO2 NPs show a high thermal stability due to the protection of the SiO2 shell. Meanwhile, we have also used the reaction of propane dehydrogenation to further verify the excellent catalytic stability of Pt–CeO2@HMSiO2 NPs. This strategy is novel, albeit efficient, and can be extended to the preparation of other nanocatalysts.