Electrosynthesis of polyfluorene in an ionic liquid and characterization of its stable electrocatalytic activity for formic acid oxidation

An air and moisture stable ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6) was utilized as an electrolyte for the direct anodic oxidation electropolymerization of fluorene. The corresponding electroactive polyfluorene films showed good redox activity and structural stability. 1H NMR and FTIR spectra together with density functional theory calculations indicated that the polymerization of fluorene occurred at the C2 and C7 positions. Scanning electron microscopy results demonstrated that smooth and compact polyfluorene films were obtained, due to the use of bmimPF6 as both the growth medium and the electrolyte. Doped polyfluorene films were examined to oxidize formic acid in 0.5 mol/L sulfuric acid by cyclic voltammetry and demonstrated stable electrocatalytic activity, showing their potential use in fuel oxidation.