Controllable Synthesis And Catalytic Properties On ZIF-8 And Its Composites

Owing to metal-organic frameworks (MOFs) with unique porosity, corresponding to adjustable pore size and ahigh specific surface, it exhibits potential applications in gas storage, catalysis, sensing and other fields. The introduction of functional guest-materials into MOFs can improve their properties, as well as further broaden their application fields; moreover, MOFs with different morphologies or sizes generally exhibit different properties. Thus it has significant importance of controllable systhesis of functional MOF materials.We successfully systhesized various inorganic NPs/ZIF-8 nanocomposites, including Au NPs (15 nm,50 nm)@ ZIF-8 single-/mLuti core-shell structures, Au NRs@ZIF-8, Au@ SiO2 @ZIF-8heterostructures via an optimized the solution phase synthetic method by control of reaction temperature and time, and choice of surfactant type, size and morphology of NPs. Combination of pore size selectivity of ZIF-8 and the localized surface plasmon resonance effect of Au NPs, Au@ ZIF-8 composties were used as visible light photocatalysts for selective oxidation of benzyl alcohol with a conversion of 25.8% for single core-shell structures, and 51.6% for multi core-shell structures.In order to undersand the effect of catalytic sites located at external surface of MOFs, we selected the rhombic dodecahedron (RD) and nano-cube (NC) ZIF-8 as model catalysts for Knoevenagel condensation. On the basis of the difference of the density of unsaturated coordination of Zn2+ on the ter minal external surface planes, ZIF-8 NCs exhibited ahigher catalytic activity compared with ZIF-8 RDs.