Noble metal-free oxidative electrocatalysts: Polyaniline and Co(II)-polyaniline nanostructures hosted in nanoporous silica

An efficient nanocomposite electrocatalyst composed of mesoporous silica (SBA-15) with polyaniline (PANI) nanostructures within its channel pores (PANI/SBA-15) is synthesized and characterized. The resulting PANI/SBA-15 is capable of chelating Co(II) ions, presumably via its nitrogen atoms on PANI/diamine groups. Both the metal-free (SBA-15/PANI) and the Co(II)-doped SBA-15/PANI nanocomposite materials showed high electrocatalytic activity for oxidation of L-ascorbic acid, with very low overpotential and high current density. The activity of PANI/SBA-15 toward oxidation of L-ascorbic acid is comparable to that obtained from a conventional Pt/C electrocatalyst.