The rational design of metal-organic frameworks (MOFs) with hollow features and tunable porosity at the nanoscale can enhance their intrinsic properties and stimulates increasing attentions. In this Communication, we demonstrate that methanol can affect the coordination mode of ZIF-67 in the presence of Co(2+) and induces a mild phase transformation under solvothermal conditions. By applying this transformation process to the ZIF-67@ZIF-8 core-shell structures, a well-defined hollow Zn/Co ZIF rhombic dodecahedron can be obtained. The manufacturing of hollow MOFs enables us to prepare a noble metal@MOF yolk-shell composite with controlled spatial distribution and morphology. The enhanced gas storage and porous confinement that originate from the hollow interior and coating of ZIF-8 confers this unique catalyst with superior activity and selectivity toward the semi-hydrogenation of acetylene.

Herein, a series of porous nano-structured carbocatalysts have been fused and decorated by Mo-based composites, such as Mo2 C, MoN, and MoP, to form a hybrid structures. Using the open porosity derived from the pyrolysis of metal-organic frameworks (MOFs), the highly dispersive MoO2 small nanoparticles can be deposited in porous carbon by chemical vapor deposition (CVD). Undergoing different treatments of carbonization, nitridation, and phosphorization, the Mo2 C-, MoN-, and MoP-decorated carbocatalysts can be selectively prepared with un-changed morphology. Among these Mo-based composites, the MoP@Porous carbon (MoP@PC) composites exhibited remarkable catalytic activity for the hydrogen evolution reaction (HER) in 0.5 m H2 SO4 aqueous solution versus MoO2 @PC, Mo2 C@PC, and MoN@PC. This study gives a promising family of multifunctional lab-on-a-particle architectures which shed light on energy conversion and fuel-cell catalysis.

The rational design of metal-organic frameworks (MOFs) with hollowf eatures and tunable porosity at the nanoscale can enhance their intrinsic properties and stimulates increasing attentions.I nt his Communication, we demonstrate that methanol can affect the coordination mode of ZIF-67 in the presence of Co 2+ and induces amild phase transformation under solvothermal conditions.B ya pplying this transformation process to the ZIF-67@ZIF-8 core-shell structures,awelldefined hollowZ n/Co ZIF rhombic dodecahedron can be obtained. The manufacturing of hollowM OFs enables us to prepare an oble metal@MOF yolk-shell composite with controlled spatial distribution and morphology.The enhanced gas storage and porous confinement that originate from the hollow interior and coating of ZIF-8 confers this unique catalyst with superior activity and selectivity towardthe semi-hydrogenation of acetylene.Toimpart new functionalities and properties,e normous efforts have been made to build metal-based composites such as metal/metal and metal/metal oxide composites. [1] Recently, the metal nanoparticles (NPs)@MOFs composite has shown alot of advantages as anew type of catalyst and thus became arising star. [2] Forexample,encapsulation of metal NPs within MOFs can prevent agglomeration and effectively enhance the thermodynamic stability. [3] Organic functional groups of MOFs could serve as Lewis base or acid to implement the metal sites in certain Lewis base-/acid-catalyzed processes. [4] Moreover,t he well-defined porous structure of MOFs can confer the shape-or size-selectivity properties if the dimension of reactants and products were carefully modulated. [5] However,w hen the catalytic process occurs inside the pores, the diffusion control by reactants or products should be taken into account. To this end, the hollow interior of MOFs would facilitate the diffusion of substrates onto the internal metal surface as well as the desorption of products. [6] To date,t he construction of hybrid metal@hollow MOFs,s imultaneously controlling their composition, morphology,a nd spatial distribution, are highly desired, but yet challenging. [7] Zeolite imidazolate frameworks (ZIF) are promising and widely used MOFs for heterogeneous catalysis due to their uniform pore size,w ell-defined morphology,a nd excellent chemical stability. [8] Thes trong coordination between metal ions and imidazolate enables the use of ZIFs in commonly used solvents and the structural integrity can survive even in water which is usually problematic for MOFs.H owever,t he construction of ah ollow interior in ZIFs,w hich will destroy the stable coordination bond, is facing tremendous challenges. Recent efforts in creating ZIF-based hollow or yolk-shell structures used at emplate such as ap olymer or oxides. [9] However,t he drastic process for template removal will damage the uniform ordered porous structure and distort the original rhombic dodecahedron morphology.Asaconsequence,t he as-prepared hollow ZIFs usually exhibit ap olycrystalline nature and problems like chan...