engleski

Application of electrospinning in the synthesis of selected metal oxide nanofibres

One-dimensional (1D) metal oxide nanostructures are promising materials for different advanced applications in electronics, energy conversion and storage, gas-sensing, catalysis and photocatalysis. To produce these nanostructures various synthesis approaches can be applaied. Among them, electrospinning method has received a remarkable interest. It allows the synthesis of very long fibres having diameter of tens to hundreds nanometers. The electrospinning is based on the effect that high voltage has on viscous, conductive polymer solution. When an applied electrostatic charge overcomes the surface tensions of the polymer solution an electrically charged polymer jet is formed. The electrospun nanofibres are then collected on the oposite charged electrode. Finally, the electrospun metal oxide nanofibres are produced by calcination of as-spun fibres. Their properties will depend on the chemical and physical parameters of electrospinning proces as well as the parameters of heating treatment. In this presentation the formation of Zn-, Ni-, Ru- and Fe-oxide nanofibers by electrospinning will be presented. The corresponding metal salts Zn(NO3)2, Zn(ac)2, Ni(NO3)2, Fe(NO3)3 or Ru(NO) (NO3)3 were dissolved into C2H5OH solvent already containing polyvinilpyrrolidone (Mw = 1300000). Electrospinning of viscous solution in the system PVP-C2H5OH-H2O-Zn(ac)2 produced fibres which were additionally heated at 400 and 600 oC producing the fibres network consisting of primary ZnO particles with maximum width between ~20 and 80 -100 nm. 1D ZnO nanoparticles were grown perpendicularly onto electrospun ZnO fibres at 160 oC in aqueous medium containing zinc(II)- acetylacetonate. In the system PVP- C2H5OH-H2O- Ni(NO3)2 at lower concentrations of Ni(NO3)2 a porous microstructure consisted of interconnected fibres was obtained, whereas at a high Ni(NO3)2 concentrations a laminar microstructure was produced. Electrospinning of viscous PVP-C2H5OH- H2O-Ru(NO)(NO3)3 solution folloed by heating of the precursor fibres at 400 oC yielded the ribbon- like RuO2/Ru nanofibers. In addition, the influence of metallic dopants on the formation and properties of a-Fe2O3 nanofibers will be also presented. The differences obtained in the synthesis of these metal oxides by electrospinning method will be shortly discussed.

electrospining ; metal oxides ; fibers

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