Electrospun iron nanofibers

The researchers observed a series of nanoprotrusions from spikes to blocks oriented perpendicular to the fiber axis. The mechanism for this process was similar to the crystallization mechanism of CNT growth from a surface. Carbon nanostructures from electrospun carbon nanofibers with iron and palladium nanoparticles were grown, respectively. In a later work, the type of carbon dictated the morphology of the resulting nanostructure. Toluene as the carbon source yielded straight nanotubes, pyridine gave coiled and Y-shaped nanotubes, and chlorobenzene formed nanoribbons. Figure 8.4 displays a variety of carbon nanostructures from rods to Y-shaped protrusions. 

Xiao, S., Shen, M., Guo, R., Wang, S. and Shi, X. 2009. Immobilization of zerovalent iron nanoparticles into electrospun polymer nanofibers Synthesis, eharaeterization, and potential environmental applications. 

Zamani P, Higgins D, Hassan F, Jiang G, Wu J, Abureden S, Chen Z (2014) Electrospun iron-polyaniline-polyacrylonitrile derived nanofibers as non-precious oxygen reduction reaction catalysts for PEM fuel cells. Electrochim Acta 139 111-116... 

The effect of salt additives on the structure of electrospun nanofibers is dependent on the actual spiiming solution used. As discussed above, the addition of ZnClj salt in PAN solution results in smaller diameter for the electrospun nanofibers. However, the addition of iron acetylacetonate (lAA) salt to the PAN solution in DMF does not lead to apparent change in the diameter of electrospun PAN nanofibers. The lAA salt also affects the solution viscosity, surface tension and conductivity by forming intermolecular interactions with PAN chains and DMF molecules. However, the changes in these solution properties are not so significant and the resultant nanofibers do not exhibit apparent diameter change. 

The approach is illustrated hy nanocomposite fibers of nanoparticle-Fe/ carbon. Nanofihers of PAN were electrospun from DMF (6.7 wt%) solutions containing 3.3 wt% of dissolved ferric acetylacetanoate. Subsequent carbonization of the nanofihers in an inert (Ar and H2) atmosphere (Hou and Reneker 2004) at high temperatures yielded carbonized nanofihers with nanoparticles of elemental iron. These were in the size range of 10-20 nm for the most part and were embedded on the surface of the fibers. Essentially, the same approach was also used with polycarbonate (PC)-palladium acetate solutions, but on calcination of the electrospun polymer nanofihers yielded inorganic palladium oxide nanofibers (Viswanathamurthi et al. 2004a) rather than Pd-nanoparticle/PC. The oxygen in keto groups of the PC was speculated to have reacted with the metal acetate to yield the oxide. Palladium nanoparticles are of particular interest in industry because of their potential use in catalysis (Briot and Primet 1991). 

---