Metal nanoparticle@porous material composites have attracted increasing attention due to their excellent synergistic catalytic performance. However, it is a challenge to introduce metal nanoparticles into cavities of porous materials without agglomeration on the exterior. Despite the progress achieved, a universal approach that can integrate different kinds of metal nanoparticles and porous materials is still highly desirable. Here we report a facile and general approach to fabricating metal nanoparticle@porous materials by microwave-triggered selective heating. The microwave can pass through the non-polar solvent and act on the polar solvent in the porous materials, causing the polar solvent to be heated, vaporized, and away from the pores of porous materials. The local void produced by the escape of polar solvent facilitates non-polar solvent containing metallic precursor to be dragged into the narrow pores, followed by further reduction, resulting in the complete encapsulation of nanoparticles. A series of metal nanoparticles@porous materials, ranging from metal-organic frameworks (MOFs) to zeolites, are successfully prepared by this method and show excellent size selectivity in catalytic reactions.

Fabrication of multifunctional catalysts has always been the pursuit of synthetic chemists due to their efficiency, cost-effectiveness, and environmental friendliness. However, it is difficult to control multi-step reactions in one-pot, especially the spatial compartmentalization of incompatible active sites. Herein, we constructed metal-organic framework (MOF) composites which regulate the location distribution of metal nanoparticles according to the reaction path and coupled with the diffusion of substrates to achieve tandem reaction. The designed UiO-66-Pt-Au catalyst showed good activity and selectivity in hydrosilylation- hydrogenation tandem reaction, because the uniform microporous structures can control the diffusion path of reactants and intermediates, and Pt and Au nanoparticles were arranged in core-shell spatial distribution in UiO-66. By contrast, the low selectivity of catalysts with random deposition and physical mixture demonstrated the significance of artificial control to the spatial compartmentalization of active sites in tandem catalytic reactions, which provides a powerful approach for designing high- performance and multifunctional heterogeneous catalysts.

Metal-organic framework (MOF) nanosheets and covalent organic framework (COF) nanosheets as emerging porous materials nanosheets have captured increasing attention owing to their attractive properties originating from the advantages of large lateral size, ultrathin thickness, tailorable physiochemical environment, flexibility and highly accessible active sites on surface, and the applications of them have been explored in a wide range of fields. Although MOF and COF nanosheets own many similar properties, their applications in various fields show significant differences, probably due to their different compositions and bonding modes. Hence, we summarize the recent progress of MOF and COF nanosheets by comparative analysis on their advantages and limitations in synthesis and applications, providing a more profound and full-scale perspective for researchers or beginners to understand this field. Herein, the categories of preparation methods of MOF and COF nanosheets are firstly discussed, including top-down and bottom-up methods. Secondly, the applications of MOF and COF nanosheets for separation, catalysis, sensing and energy storage are summarized. Finally, based on current achievements, we put forward our personal insights into the challenges and outlooks on the synthesis, characterizations, and promising applications for future research of MOF and COF nanosheets.

The development of artificial enzyme mimics has been rapidly growing in recent years, and it is attracting increasing attention owing to their remarkable advantages over natural enzymes. Herein, we developed a general and facile method to fabricate efficient glutathione peroxidase (GPx) mimics by grafting selenium-containing molecules (phenylselenylbromide, PhSeBr) to a Zr(IV)-based UiO-66-NH₂ framework. In the presence of glutathione (GSH) serving as substrate, the fabricated UiO-66-Se catalysts can catalyze the reduction of hydroperoxides. The as-prepared UiO-66-Se systems show good catalytic activity over three cycles. These high-efficiency GPx mimic metal-organic frameworks (MOFs) are endowed with excellent thermal and structural stability, providing a promising avenue for the development of artificial enzyme mimics.

A facile encapsulation strategy for the preparation of metal layer/metal–organic framework (metal/MOF) hybrid thin films, by alternately growing MOF thin films and sputter-coating metal layers, is reported. The controlled species of the MOF thin films and metal layers, as well as the designed thickness of MOF thin films, endow the resulting hybrid thin films with improved functional and design flexibility. Importantly, the metal/MOF hybrid thin films, with well-defined sandwich structures, exhibit excellent selective catalytic activity, derived from MOFs acting as molecular sieves and the metal layers providing active sites.