Abstract: A supported catalyst useful in the preparation of an electrode for an electrochemical cell which comprises the residue remaining after heating at about 500.degree. to about 800.degree. C. a transition metal and a polymer such as polyvinylpyridine all adsorbed on a support material. Useful electrodes are prepared by combining the supported catalyst with a current collector.

Abstract: A membrane-electrode structure for use in an electrochemical cell comprising an ion exchange membrane with a cathode layer and an intermediate layer between the cathode and the membrane. The intermediate layer comprises about 5 to 80% by weight of inorganic solid particles and about 95 to 20% by weight of an ionic conductive polymeric binder.

Abstract: A supported catalyst useful in the preparation of an electrode for an electrochemical cell which comprises the residue remaining after heating at about 500.degree. to about 700.degree. C. a transition metal and a polymer such as polyvinylpyridine all adsorbed on a support material. Useful electrodes are prepared by combining the supported catalyst with a current collector.

Abstract: Methods are disclosed to control reverse current flow in stacks of membrane electrolytic cells during off-line periods. One method includes the introduction of a stripping gas flow to the anolyte solution of the cells during an interruption of normal positive current flow. In another embodiment, reverse current flow is controlled by introducing at least one soluble reducing agent to the anolyte solution during an interruption of normal positive current flow. Also disclosed is a porous sparging apparatus useful in introducing a stripping gas flow to a stack of membrane electrolytic cells.