SURFACE MODIFICATION OF ACETYLENE BLACK B Y OXYGEN PLASMA PROCESSING AND APPLICATION TO GAS-DIFFUSION ELECTRODE

The authors have investigated the surface properties which are electri c conductivity, wettability, surface functional groups, and rate const ant of H2O2 decomposition of surface modified acetylene black (AB) by low temperature oxygen plasma of dc glow discharge. This work also des cribes the relations between the surface properties and the electroche mical behavior in an aqueous KOH solution of the gas diffusion electro des with oxygen plasma processed AB. The results are as follows; i) th e conductivity of AB decreasing with processing time. ii) the AB surfa ce changing from hydrophobic to hydrophilic. iii) making it possible t o get AB high H2O2 decomposition ability by the plasma processing. The se facts would be illustrated by the increase of oxygen functionalitie s such as aromatic -OH, >C=O, -COOH etc. of AB surface. The polarizati on and discharge behaviors of oxygen electrode with AB have been much improved by the plasma processing. These can be regarded as forming th e stable three phase zone owing to adapt wettability, high H2O2 decomp osition ability, and developed fine pore of the AB electrode.