Aqueous UV–VIS spectroelectrochemical study of the voltammetric reduction of graphene oxide on screen-printed carbon electrodes

• Voltammetric reduction of graphene oxide is easily accomplished on the surface of screen-printed electrodes.
• UV–VIS absorption spectroelectrochemistry in reflection mode is used for the very first time on screen-printed electrodes to monitor in real time the electrochemical reduction of graphene oxide.
• Raman spectroelectrochemistry in combination with miniaturised screen-printed electrodes provides useful information to monitor the voltammetric reduction of graphene oxide.

Two graphene oxide (GO) materials with different layer size and proportion of functional groups in the basal planes (hydroxyl and epoxy) and in the edges (carbonyl and carboxyl) were used to modify the surface of commercially available screen-printed electrodes. Cyclic voltammetry in 0.1 M KNO3 was evaluated as an easy to use electrochemical methodology to reduce GO attached to the surface of screen-printed electrodes (SPEs). A cathodic peak related to the reduction of GO was identified, and the peak potential was correlated to the difficulty to reduce GO to electrochemically reduced graphene oxide (ERGO) depending on the functional groups present in the basal plane and in the edges of the original GO monolayers. Time-resolved UV–VIS absorption spectroelectrochemistry in near-normal reflection mode on a screen-printed electrode is used for the very first time as an in situ characterization technique for real-time monitoring unambiguously the electrochemical reduction of graphene oxide.