Preparation And Catalytic Properties Of A Novel Metal Organic Framework And Au@Pt@ZIFs Composite

Metal-organic frameworks(MOFs)represent a class of crystalline porous material,formed by the self-assembly of metal ions and organic linkers.Because of their high specific surface area,adjustable pore size and easy modification,MOFs have attracted extensive research in areas such as catalysis,gas storage,fluorescence and magnetism.In this paper,a new MOF was firstly synthesized and used to explore its multifunctional catalytic performance.Then a variety of core-shell composite catalysts were prepared through particle encapsulation method,using zeolitic imidazo late frameworks ZIF-67 and ZIF-8 as the host materials.A new three-dimensional microporous MOF,[Zn(ATA)(bpd)]?(1Zn)was developed through liquid diffusion method by combining nitrogenous ligand(bpd),2-amino terephthalic acid(ATA)and transition metal ion Zn2+.The morphology of 1Zn crystal can be controlled by using different solvents and surfactants in the direct mixing process.Herein,1Zn microcrystals were obtained in a variety of morphologies such as microspheres,microblocks,microsheets,microplates and microrods.The synthesized 1Zn crystals were used for Knoevenagel condensation reaction and organic dye degradation.The results showed that 1Zn possessed multifunctional catalytic behavior,which not only can effectively promote Knoevenagel condensation reaction,achieving 80%conversion,but also selectively degrade methyl orange,obtaining 90%degradation efficiency.In addition,it is interesting to find that 1Zn crystals with various morphologies showed different catalytic activity.In this paper,Au nanorods(Au NRs),Au@Pt nanorods(Au@Pt NRs)and Au@Pt nanorods with unique hollow structure(Au@Pt HNRs)were preformed,and ZIFs crystals with different size were prepared,then six multi-core-shell composite materials(Au NRs@ZIF-67,Au@Pt NRs@ZIF-67,Au@Pt HNRs@ZIF-67,Au NRs@ZIF-8,Au@Pt NRs@ZIF-8 and Au@Pt HNRs@ZIF-8)were synthesized through particle encapsulation method.A series of characterizations of these composites were carried out.The results showed that both ZIF-67 and ZIF-8 could successfully encapsulate the preformed metal nanoparticles,without affecting the structure of the host materials and nanoparticles.