Study on Oxidation State Dependent Electrocatalytic Ability for I/I3 Redox Reaction of Reduced Graphene Oxides



The influence of oxidation states on electrocatalytic abilities for I3 reduction is discussed for reduced graphene oxide (rGO), which is a promising catalyst of counter electrodes for dye-sensitized solar cells (DSSCs). The oxidation states of rGO can be controlled via a photothermal reduction process by varying exposure times. The results reveal that the rGO with lower oxidation state shows smaller charge transfer resistance at the electrode/electrolyte interface and better electrocatalytic ability attributed to higher standard heterogeneous rate constant (k0) and reasonable electrochemical surface area (Ae) for I3 reduction, both are quantitatively determined by a rotating disk electrode system using the Koutecký[BOND]Levich equation.