Electrochemically controlling oxygen functional groups in graphene oxide for the optimization in the electro-catalytic oxidation of dihydroxybenzene isomers and L-methionine

In order to control the conductivity and oxygen functional groups in GO, GO modified glassy carbon (GC) electrodes were pretreated by electrochemical reduction at different potential and were investigated by Raman spectroscopy. The resulting GO/GC electrodes were presented for the electroanalysis of catechol (CC), hydroquinone (HQ), and L-methionine (L-Met). It was found that simultaneous determination of the dihydroxybenzene isomers could be achieved and the over-potential of L-Met was significantly decreased at the as-prepared GO/GC electrodes. In addition, GO/GC electrodes pretreated at different potential exhibited various electro-catalytic activities. The role of conductivity and residual oxygen-containing functional groups on the electro-catalytic activity was discussed. The results shows that sometimes neither GO nor completely reduced GO demonstrates the best properties in electroanalysis. The optimal conditions can be obtained by electro-reduction at different potential.