A study of glassy carbon electrodes modified with azobenzene derivatives

► GC electrodes were modified with three azobenzene derivatives by diazonium reduction. ► The blocking action of aryl films for oxygen and ferricyanide reduction was studied. ► The blocking effect depends on the diazonium salt and the grafting procedure used. ► O2 reduction on modified electrodes was less inhibited than ferricyanide reduction. ► Azobenzene-modified GC electrodes showed the best barrier properties.