Noble metal nanoparticles or subnanometric particles confined in zeolites, that is, metal@zeolite, represent an important type of functional materials with typical core–shell structure. This type of material is known for decades and recently became a research hotspot due to their emerging applications in various fields. Remarkable achievements are made dealing with the synthesis, characterization, and applications of noble metal particles confined in zeolites. Here, the most representative research progress in metal@zeolites is briefly reviewed, aiming to boost further research on this topic. For the synthesis of metal@zeolites, various strategies, such as direct synthesis from inorganic or ligand‐assisted noble metal precursors, multistep postsynthesis encapsulation and ion‐exchange followed by reduction, are introduced and compared. For the characterization of metal@zeolites, several most useful techniques, such as electron microscopy, X‐ray based spectroscopy, infrared and fluorescence emission spectroscopy, are recommended to check the successful confinement of noble metal particles in zeolite matrix and their unique physiochemical properties. For the applications of metal@zeolites, catalysis and optics are involved with an emphasis on catalytic applications including the size‐dependent catalytic properties, the sintering‐resistance properties, the substrate shape‐selective catalysis, and catalysis modulation by zeolite microenvironment.

No abstract

No abstract

Methanol carbonylation is known as a classic reaction of homogeneous catalysis with large-scale industrial applications. The heterogenization of homogeneous catalysts is being pursued to address the issues of catalyst deactivation and separation encountered in homogeneous systems. Herein, we report the strategy of stabilizing isolated rhodium cations by MFI zeolite to construct highly active Rh@MFI zeolite catalysts for heterogeneous methanol carbonylation. The formation of a zeolite-stabilized [Rh­(CO)2I2] analogue during the reaction has been identified to catalyze methanol carbonylation. Moreover, the structure of the zeolite can significantly promote methanol carbonylation within channels through electronic confinment. As a result, a state of the art turnover frequency of 3950 molacetyl/(molRh h) is achieved with the Rh@ZSM-5 catalyst at a low reaction temperature of 423 K. This work presents a simple and general approach toward the heterogenization of homogeneous catalysts for targeted chemical transformations.

No abstract