抄録
Both the carbon oxidation (COR) and oxygen evolution reactions (OER) for Ketjen black, natural graphite, and vapor grown carbon fibers (VGCF) are investigated in a KOH aqueous solution by using a rotating disk ring electrode. The onset potentials for COR and OER are determined and the reaction kinetics, especially the weight loss rate ascribed to COR, are also evaluated. For instance, the onset potentials of VGCF are determined to be 0.38 V against Hg|HgO for COR and as 0.68 V for OER. In addition, the weight loss rate of VGCF is estimated as 0.002∼0.007% h−1 at 0.6 V vs. a reference electrode, which is the much lower than that for Ketjen black. Thus, the results of this study give guidance for carbonaceous materials to use as the positive electrode of a rechargeable air battery where an alkaline medium is used as electrolyte.
