Carbon gas diffusion electrodes promoted with silver and operating on air or oxygen in alkaline medium. Physical parameters of electrodes and their components

From the ratio of hydrophobic to hydrophilic pore volumes determined after a long-term exposure of the gas or active layer to water, the strong hydrophobic nature of the teflonized carbon black contained in carbon-based gas diffusion electrodes was confirmed. This material proves better than Teflon in Teflon-bonded active carbon electrodes, whose hydrophobicity is adversely affected on heating and the mechanical strength of the layer decreases. Measurement of the penetration of water and rate of flow of oxygen revealed that the teflonized carbon black ensures two essential functions of the gas diffusion electrode: feeding the active layer with oxygen and prevention of flooding of the gas pores.