Investigations of the electrochemical properties of activated carbon and carbon black

Potentiometric studies have been carried out on activated carbon and carbon black immersed in aqueous solutions of electrolytes. The samples studied were subjected to various modifying treatments: demineralization, oxidation in liquid and gaseous phases, saturation with hydrogen, and degassing. It was found that the potential of carbon increases during contact with the electrolyte solution; the amount of anions in the solution decreases with a simultaneous rise of the solution pH. Measurements of the potentials of the carbon samples of large specific surface area immersed in buffer solutions or solutions of established pH have shown that in the range 2.0 < pH < 7.00 the potential of the carbon material decreases with increasing pH. It was also found that the potential of the carbon powder electrode depends on the kind and concentration of the electrolyte solution as well as on the modification of the carbon surface.