In-situ synthesis of polynaphthylamine/graphene composites for the electrochemical sensing of benzoic acid

Polynaphthylamine/graphene composites have been synthesized by an in situ polymerization of the naphthylamine monomers and graphene. The polynaphthylamine/graphene composites were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), Raman spectrum and Fourier transform infrared spectrum (FTIR). The analytical results show that the polynaphthylamine/graphene composites possess hexagonal graphite-2H phase and are composed of irregular polynaphthylamine particles and graphene nanosheets with the wrinkles and folds. The bare glassy carbon electrode was modified with the polynaphthylamine/graphene composites for the detection of benzoic acid. The polynaphthylamine/graphene composites modified glassy carbon electrode exhibits an irreversible oxidation cyclic voltammogram (CV) peak located at +0.29 V. The significant enhancement in the current response is observed as the increase of the scan rate, benzoic acid concentration and decrease of the pH value of the electrolyte. The current response of the CV peak of the benzoic acid exhibits a linear relationship with the benzoic acid concentration ranging from 0.001-2 mM. The detection limit is 0.34 M. The polynaphthylamine/graphene composites modified glassy carbon electrode reveals great promising for the determination of benzoic acid.