Fabrication Of Metal-Organic Framewok@Fibers Composite By The Spray Technique And Their Catalytic Performance

Metal-organic frameworks(MOFs)have received a great deal of attention since synthesized in the 1990s,which consisting of metal ions or clusters joined together by organic ligands through strong coordination bonds.MOFs are wildly applied to gas adsorption and separation,catalysis,drug transport and sensor due to their high specific surface area,adjustable pore sizes and unsaturated metal sites.Compared with 3D bulk MOFs,2D MOFs nanosheets have unique physical and chemical properties originated from their large lateral dimension and ultrathin thickness.However,the majority of MOFs are prepared in powder state needing reprocessing for further application.So far,many efforts have been made in integrating MOFs into different substrates.As a flexible substrate,fibers have drawn much attention due to the fact that it can be folded into various shapes in conformity to practical requirements.Till now,a series of synthesis methods have been developed to grow MOFs on the surface of fibers,such as in situ growth?seeding and secondary growth and supramolecular assembly,many of which require long processing time and high temperature.In this article,2D MOFs nanosheets were directly attached to the surface of fibers by spray technique.We have successfully prepared CuBDC@carbon fibers,CuBDC@cotton fibers,CuBDC@nylon fibers,Cu(1,4-NDC)@carbon fibers,Cu(2,6-NDC)@carbon fibers and Cu(2-atp)@carbon fibers.A metal ion solution underwent ultrasonic atomization fells on the surface of fibers which adsorb a large amount of organic ligand solution,then the metal ions diffuse along the fiber's direction and react with organic ligands.Finally the resulting MOFs nanosheets are pretty dense and evenly wrapped around fibers,which like build 2D MOFs "armor" on fibers.The morphology,crystal structure and chemical structure of MOFs@fibers were studied by SEM,EDS,XRD and FT-IR.The MOFs nanosheets in CuBDC@carbon fibers,Cu(1,4-NDC)@carbon fibers,Cu(2,6-NDC)@carbon fibers and Cu(2-atp)@carbon fibers are stacked on top of each other due to interlayer force and completely wrapped around the carbon fibers along the direction of carbon fibers.The CuBDC nanosheets in CuBDC@cotton fibers and CuBDC@nylon fibers were in agglomeration and they show poor dispersion on the surface of cotton fibers and nylon fibers.CuBDC@carbon fibers were used as a filter for catalytic reduction of 4-nitrophenol.When 4-nitrophenol solution in the presence of NaBH4 permeated through CuBDC@carbon fibers,the 4-nitrophenol was reduced to 4-aminophenol.The same concentration of the 4-nitrophenol solution in the presence of NaBH4 had different conversion rate when they permeated through different layers of CuBDC@carbon(1,3,5).The more layers of CuBDC@carbon fiber are stacked,the better effect of catalytic reduction of 4-nitrophenol is achieved.