Method of making a catalytic lead-based oxygen evolving anode

A method of making a catalytic lead-based, oxygen evolving anode comprising catalytic titanium particles activated with a minor amount of a ruthenium-based electrocatalyst, which particles are uniformly distributed on and partly embedded in the surface of an anode base of lead or lead alloy, whereby they are electrically connected to said base and present a large exposed active surface projecting from said base for evolving oxygen at a reduced potential at which the underlying lead or lead alloy at the surface of the anode base remains electrochemically inactive, comprising the steps of:

• (a) producing said catalytic titanium particles by impregnating titanium sponge particles having a size greater than 300 microns with an activating solution containing thermally decomposable manganese and ruthenium compounds in proportions corresponding to molar ratios of Mn/Ru of between about 7/3 and about 9/1, then drying and heat treating said particles to convert said compounds into oxides of ruthenium and manganese and repeating this impregnating, drying and heat treating sequence at least once to provide an effective concentration of ruthenium amounting to less than 6% by weight of the titanium sponge particles;
• (b) applying to the surface of said anode base a uniform distribution of said catalytic titanium sponge particles in an amount corresponding to at least 400 grams of titanium sponge per square meter of said surface;
• and
• (c) pressing said particles against said surface until they are partially embedded therein and firmly anchored to said anode base in good electrical contact therewith.