Novel properties of polyaniline nanofibers coated with polycatechol

Polyaniline nanofibers coated with polycatechol, FcPAn/polycatechol, have been prepared with two steps by using repeated potential cycling. First, aniline in a solution containing ferrocenesulfonic acid (Fc) was polymerized on a platinum electrode to form polyaniline nanofibers (FcPAn); second, catechol was polymerized on the polyaniline nanofibers to form FcPAn/polycatechol. The scanning electron microscopy (SEM) images show that the diameters of FcPAn and FcPAn/polycatechol fibers are in the range of 40–60 and 70–90 nm, respectively. The IR and XPS spectra of FcPAn/polycatechol indicate that OH groups and ferrocenesulfonic acid are contained in FcPAn/polycatechol. FcPAn/polycatechol has a good electrochemical activity in the wide pH range. The cyclic voltammogram identifies that FcPAn/polycatechol in the Na2SO4 solution with pH 11.0 still has the electrochemical activity at the scan rate of 60 mV s−1. The conductivity of FcPAn/polycatechol is 0.48 S cm−1, which is slightly affected by water. FcPAn/polycatechol nanofibers with the diameter of 70–90 nm have a higher catalytic activity to the electrochemical oxidation of ascorbic acid, compared with FcPAn/polycatechol fibers with the diameter of 140–210 nm.