Fabrication of conducting polymer-gold nanoparticles film on electrodes using monolayer protected gold nanoparticles and its electrocatalytic application

We wish to report a simple and new strategy for the fabrication of gold nanoparticles-conducting polymer film on glassy carbon (GC) and indium tin oxide (ITO) surfaces using 5-amino-2-mercapto-1,3,4-thiadiazole capped gold nanoparticles (AMT-AuNPs) in 0.01 M H2SO4 by electropolymerization. The presence of amine groups on the surface of the AuNPs was responsible for the deposition of the AMT-AuNPs film on the electrode surface. The atomic force microscopy (AFM) studies reveal that the fabricated p-AMT-AuNPs film showed homogeneously distributed AuNPs with a spherical shape of ∼8 nm diameter. The XPS spectrum shows the binding energies at 83.8 and 87.5 eV in the Au 4f region corresponding to 4f7/2 and 4f5/2, respectively. The position and difference between these two peaks (3.7 eV) exactly match the value reported for Au0. The N1s XPS showed three binding energies at 396.7, 399.6 and 403.3 eV, corresponding to the NH, –NH– and –N+H–, respectively, confirming that the electropolymerization proceeded through the oxidation of –NH2 groups present on the periphery of the AMT-AuNPs. The application of the present p-AMT-AuNPs modified electrode was demonstrated by studying the electro reduction of oxygen at pH 7.2. The p-AMT-AuNPs film enhanced the oxygen reduction current more than three times than that of p-AMT film prepared under identical conditions.