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 H2 SO4 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 O2 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.