Electroreduction of oxygen on gold nanoparticle/PDDA-MWCNT nanocomposites in acid solution

The electrochemical reduction of oxygen has been studied on gold nanoparticle (AuNP)/poly(diallyldimethylammonium chloride) (PDDA)-multi-walled carbon nanotubes (MWCNTs) modified glassy carbon (GC) electrodes in 0.5 M H2SO4 using the rotating disk electrode (RDE) technique. The AuNP/PDDA-MWCNT catalysts were prepared using an electrostatic layer-by-layer (LBL) technique. The composite electrode was electrochemically characterized by cyclic voltammetry in an O2-free electrolyte. The oxygen reduction behaviour of these electrodes was compared with that of a PDDA-MWCNT/GC electrode. The AuNP/PDDA-MWCNT catalysts showed a remarkable electrocatalytic activity towards O2 reduction in acid media. The half-wave potential of O2 reduction on the AuNP/PDDA-MWCNT catalyst shifted more than 200 mV to more positive potentials as compared to that of a PDDA-MWCNT/GC electrode. The kinetic parameters of O2 reduction were determined and the specific activity of the hybrid electrodes was higher than that of bulk gold.