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 specific surface area is 21,000 cm-1 and its porosity is 0.97; thus, it is ideally suited for coulometric cells. Although the material is fragile, it can be bored with steel or glass tubing. The most effective cells 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 cell, 0.5 mm long, the electrode volume was 0.4 microL, yet it yielded unit coulometric efficiency at 1.0 mL/min. The pressure required for higher flow rates caused electrode failure. Longer electrodes yielded cells with unit coulometric efficiency up to the system limits near 3 mL/min.