“Ship-in-Bottle” Strategy to Encapsulate Shape-Controllable Metal Nanocrystals into Metal–Organic Frameworks: Internal Space Matters

“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 o-chloronitrobenzene to produce o-chloroaniline, the as-prepared shape-controllable MNCs@MOFs exhibited excellent synergistic effects on both raw materials conversion and byproducts inhabitation efficiencies.