Nadezda Alexeyeva

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.

Electrochemical Reduction of Oxygen on Multiwalled Carbon Nanotube Modified Glassy Carbon Electrodes in Acid Media

The electrocatalytic reduction of oxygen has been studied on multiwalled carbon nanotube (MWCNT) modified glassy carbon (GC) electrodes in 0.5 M H 2 SO 4 solution using the rotating disk electrode technique. The oxygen reduction behavior of oxidatively pretreated and untreated MWCNT modified GC electrodes was compared. The results obtained indicate that the electrocatalytic properties of untreated MWCNTs toward O 2 reduction in acid media are noticeably better than that of pretreated MWCNTs. This effect is caused by catalyst impurities which remain in the nanotubes prepared by chemical vapor deposition and can be largely removed by treatment in acids.