Ag nanoparticles decorated polyaniline nanofibers: synthesis, characterization, and applications toward catalytic reduction of 4-nitrophenol and electrochemical detection of H2O2 and glucose

Polyaniline nanofibers (PANINFs) have been facilely prepared by electrochemical polymerization of aniline monomers in acidic aqueous media without using any templates and surfactants. The subsequent treatment of such nanofibers with a AgNO3 aqueous solution leads to in situ chemical reduction of Ag+ on them to form Ag nanoparticles decorated PANINFs (AgNPs/PANINFs) nanocomposites. We investigated the catalytic activity and electrochemical properties of these nanocomposites. It is found that such nanocomposites exhibit excellent catalytic activity toward reduction of 4-nitrophenol to 4-aminophenol by NaBH4 and exhibit remarkable catalytic performance for H2O2 reduction. The enzymeless H2O2 sensor constructed using the nanocomposites shows a fast amperometric response time of less than 3 s. The linear range and detection limit are estimated to be from 0.1 mM to 60 mM (r = 0.998) and 1.7 mu M at a signal-to-noise ratio of 3, respectively. We have fabricated a glucose biosensor by immobilizing glucose oxidase into the AgNPs/PANINFs-modified glassy carbon electrode for glucose detection. This sensor exhibits good response to glucose. The linear response range is estimated to be from 1 mM to 12 mM (r = 0.997) at -0.58 V. The detection limit is estimated to be 0.25 mM at a signal-to-noise ratio of 3.