Electrogenerated chemiluminescence of luminol at a polyaniline/graphene modified electrode in neutral solution

Abstract

Polyaniline (PANI) was in situ electrochemical polymerized on an electrochemical reduced graphene oxide (GO) modified glassy carbon electrode (GCE) to prepare PANI-graphene (GR) composite modified GCE (PANI-GR-GCE). The modified electrode was characterized by atomic force microscopy, IR and electrochemical techniques. The results showed that the multi-layer of PANI and graphene could be formed on a bare electrode. The electrochemical signal was improved greatly compared with the PANI or the GR modified electrodes, respectively. Electrogenerated chemiluminescence (ECL) of luminol was comparatively investigated at the PANI-GCE, the GR-GCE, and the PANI-GR-GCE in neutral phosphate buffer solution (PBS). The anodic luminol ECL was inhibited greatly and the cathodic luminol ECL was enhanced at the GR-GCE. Extremely weak luminol ECL peaks were obtained at the PANI-GCE except one strong ECL obtained at high potential range. The PANI-GR composite exhibited apparent electrocatalytical effect on luminol oxidation, and as a result, the intensity of anodic ECL located at 0.50V was enhanced two magnitudes compared with other two modified electrodes. Several impact factors, such as the supporting electrolytes, the pH, the potential scan rate, and the different atmosphere, were studied. The mechanism of luminol ECL was also proposed.