Characterization of anodically oxidized carbon black
Horita Kiyoshi; Li Xu
Abstract:Characterization of anodically oxidized carbon black (CB) has been investigated from the discussion of its surface properties, such as wettability, electric conductivity, rate constant of H2O2 decomposition. This work also describes the relationship between the surface properties and the electrochemical behavior of the electrodes with anodically modified CB in an aqueous KOH solution. The results are as follows: the CB surface changes hydrophobic to hydrophilic; the conductance of CB decreases with the oxidation; and the oxidation enhances the H2O2 decomposition ability of CB. The polarization behavior of an oxygen electrode has been significantly improved by the oxidation. From experiment using a rotating disk electrode, the electrochemical reduction of oxygen on CB surface is mainly a two-electron pathway forming an intermediate, H2O2, and no change in the number of electrons per mole of oxygen has been observed between the untreated CB electrode and the oxidized one. The electrode reaction rate of the oxidized CB electrode has been higher than that of the untreated CB electrode. The diffusion rate of the active material in the oxidized CB electrode was higher than that of the untreated CB electrode. Key Words:carbon black, anodic oxidation, surface modification, oxygen electrode, rotating disk electrode