Polyaniline nanoconical array on carbon nanofiber for supersensitive determination of nitrophenol

The polyaniline nanoconical array coated carbon nanofibers (PANI-array@CNF) were successfully fabricated by the polymerization of aniline monomers on the surface of the carbonized electrospun polyacrylonitrile fibers at low temperature. The morphology and electrochemical activity of the PANI-array@CNF are much dependent on the polymerization time and feeding speed of ammonium persulfate. In contrast with CNFs, the specific surface area and pore volume of the PANI-array@CNF become larger. Compared to commercial PANI powder, the oxidation/reduction response of PANI-array@CNF is dramatically enhanced due to the abundant active sites of the PANI nanoconical array perpendicular to the CNF surface. The PANI-array@CNF modified-glassy carbon electrode (PANI-array@CNF/GCE) exhibits outstanding electrochemical response to the reduction of o-ni-trophenol (o-NP), m-nitrophenol (m-NP) and p-nitrophenol (p-NP). The PANI-array@CNF/GCE delivers a superhigh detection sensitivity for individual analysis of nitrophenol isomers, with the limit of detection down to 0.5 nM for o-NP, 1.0 nM for m-NP and 1.5 nM for p-NP. In addition, the fabricated sensor has been successfully applied for the simultaneous determination of o-NP and p-NP in lake and tap water samples. The PANI-array@CNF based sensor has good repeatability, high stability and excellent selectivity. It demonstrates a great potential for highly sensitive determination of nitrophenols in environmental pollution system.