Palladium Nanoparticles Encapsulated in a Silicalite‐1 Zeolite Shell for Size‐Selective Catalysis in Liquid‐Phase Solution

Abstract

Size‐selective catalysis is of great significance in both fundamental research and industrial applications. One well‐known example is zeolite‐based catalysts, which show remarkable size selectivity in gas‐phase reactions. However, very few of these catalysts are realized in liquid‐phase solution. Herein, we report an efficient route to produce a composite composed of Pd nanoparticles encapsulated in a silicalite‐1 zeolite shell. This composite shows sharp size‐selective catalysis in the hydrogenation of olefin aldehydes in aqueous solution. Owing to the pore‐size limitation of the silicalite‐1 zeolite shell (0.53×0.56 nm), the catalyst shows high activity in the hydrogenation of 3‐methyl‐2‐butenal (0.38×0.62 nm) and cinnamaldehyde (0.54×0.92 nm) but no activity for the hydrogenation of 3,3‐diphenylacrylaldehyde (0.81×1.0 nm). A catalyst with this type of structure can be applied to load other metal nanoparticles and can serve as a useful platform to study heterogeneous size‐selective catalysis in liquid solution.

Selective steam reforming of n‐dodecane over stable subnanometric NiPt clusters encapsulated in Silicalite‐1 zeolite

“…The chemical states of Ni nanoparticles encapsulated in zeolites were evaluated by XPS analysis. No obvious signals were observed in 2Ni@S‐1 and 2Ni0.5Pt@S‐1 samples as shown in Figures S8 and S9, indicating almost all Ni and Pt nanoparticles are fixed inside the S‐1 zeolite., which was coincident with TEM observations. After ball milling treatment in zirconia balls for 24 hr (Figures S10–S12).…”

Surfactant‐Free Palladium Nanoparticles Encapsulated in ZIF‐8 Hollow Nanospheres for Size‐Selective Catalysis in Liquid‐Phase Solution

“…Furthermore, combining the functions of MOFs with metal cores to create multifunctional core@shell nanocomposites has been extensively investigated . Unlike other porous materials, MOFs can be used as an ideal shell material for confined catalysis and size‐selective catalysis, which is of great significance for both fundamental research and industrial applications …”

Recent developments in the control of selectivity in hydrogenation reactions by confined metal functionalities

“…Owing to the limited size of the zeolite apertures, 3-methyl-2-butenal (0.38 × 0.62 nm) and cinnamaldehyde (0.54 × 0.92 nm) could diffuse into the NPs but not the larger 3,3-di-phenylacrylaldehyde (0.81 × 1.0 nm). 59 The transformation of 2D zeolites into 3D ones also promotes a high intermolecular selectivity as demonstrated by several studies. For example, 3-nitrotoluene was hydrogenated over Pd@MCM-22, 56 but not 1-nitronaphthalene, whose dimensions (0.73 × 0.66 nm) are larger than the zeolite pores (0.41 × 0.51 nm).…”