Electrochemical Oxidation Mechanism of Highly Oriented Pyrolytic Graphite in Sulfuric Acid Solution

Degradation of the electrode materials is one of the most important issues for commercialization of polymer electrolyte fuel cells (PEFCs). Among the reasons for the degradation, carbon corrosion is a major concern for the deterioration of the activity of Pt supported carbon (Pt/C) catalyst as well as “ flooding ” in the electrode layer [1]. Unfortunately, the details of stability and reaction mechanism of carbon materials in PEFCs have not been well clarified so far. To clarify the oxidation mechanism, electrochemical oxidation mechanism of HOPG (highly oriented pyrolytic graphite) with regard to formation of surface functional groups was studied. [2, 3]. Freshly cleaved HOPG (Advance Ceramics, STM-1 grade) was used as a model electrode. A three-electrode cell equipped with Ag|AgCl as a reference electrode an