Electrochemical Behaviour of HOPG and CVD‐Grown Graphene Electrodes Modified with Thick Anthraquinone Films by Diazonium Reduction

Highly oriented pyrolytic graphite (HOPG) and graphene grown on Ni (Ni-Gra) or Cu (Cu-Gra) by chemical vapour deposition were modified with thick anthraquinone (AQ) films (7−60 nm) by redox grafting of the pertinent diazonium salt. Glassy carbon (GC) electrodes were used for comparison. The AQ-modified GC electrodes showed excellent blocking properties towards the Fe(CN)63−/4− redox probe, although it was noted that in the case of Ni-Gra and Cu-Gra, the blocking ability depended strongly on the underlying substrate. Oxygen reduction studies revealed good electrocatalytic activity of AQ-modified HOPG, Ni-Gra, and Cu-Gra, compared with the bare electrodes.