The proposed electrons transfer mechanism for graphene well-wrapped UiO-66-NH2 octahedrons.

Ship-in-bottle" strategy used for encapsulating small metal clusters into metal−organic frameworks (MOFs) has been well established in the past decades, whereas immobilizing shape-controllable metal nanocrystals' (MNCs) which was expected to show "shape effects" in catalysis remains as a challenging work. Herein, by the new developed pore-expanding pattern of digging holes in the central of MOFs crystals to create mesopores-concentrated structure, a successful metal nanocrystal shapes manipulation (cubes, rods, triangular bipyramids, icosahedrons, truncated octahedrons, and concave cubes) in the cavities was accomplished. Meanwhile, the tight relations among MOFs internal space types, sizes, and the reduced MNCs' location and shape evolutions in the encapsulation process were revealed for the first time. In catalyzing the reaction of hydrogenation of ochloronitrobenzene to produce o-chloroaniline, the as-prepared shape-controllable MNCs@MOFs exhibited excellent synergistic effects on both raw materials conversion and byproducts inhabitation efficiencies.

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Inhibiting the recombination of electron and holes plays an essential role in photocatalytic process, particularly for metal-organic frameworks (MOFs), which had long been anticipated as high-efficient photocatalysts. Herein, we introduce a new strategy to make efficient separation of electrons and holes for the MOF-based photocatalyst, UiO-66-NH . At first, encapsulation of Pt nanoparticles (NPs) into UiO-66-NH (Pt@U6N) to shorten the electrons transport distance inside of MOF crystals, then using graphene oxide to wrap the external surface of Pt@U6N to facilitate the electrons transfer on the surface. The designed structure was found to possess superior H -generation ability compared to only inside or outside decorated samples, highlighting that the enhanced property strongly correlates with the inhibited recombination of electrons and holes by the inside/outside modification strategy. These findings suggest a synergistic effect of Pt NPs and graphene oxide on UiO-66-NH and reveal a new modification strategy to enhance the catalytic activity of the photocatalysts.

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