CARBONIZED MICROCELLULAR FOAM-BASED POROUS FLOW-THROUGH ELECTRODES WITH UNIT COULOMETRIC EFFICIENCY

The carbon foam used was pyrolyzed from PAN at 1100-degrees-C. Its spe cific surface area is 21 000 cm-1 and its porosity is 0.97; thus, it i s ideally suited for coulometric cells. Although the material is fragi le, it can be bored with steel or glass tubing. The most effective cel ls consisted of cylindrical segments of foam which were from 0.5 to 3. 0 mm long inside of a 1.0 mm in diameter glass tube. In the smallest c ell, 0.5 mm long, the electrode volume was 0.4 muL, yet it yielded uni t coulometric efficiency at 1.0 mL/min. The pressure required for high er flow rates caused electrode failure. Longer electrodes yielded cell s with unit coulometric efficiency up to the system limits near 3 mL/m in.