TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preparation (Claimed): Preparation of the electrocatalyst comprises either deposition of the electrocatalyst using a reductant, or thermal treatment of a precursor comprising a rhenium compound with hydrogen. Preferred Components: The ruthenium alloy comprises 0.01-50 atom% of at least one or two metals comprising 0.1-25 (preferably 1-5) atom% of palladium, 0.1-25 (preferably 1-5) atom% iridium, 0.1-25 (preferably 0.1-5) atom% of rhenium, 0.1-25 atom% of platinum, 0.1-25 atom% of osmium and/or balance ruthenium. The reductant is an alkali borohydride. The rhenium compound is ammonium perrhenate. The electrocatalyst is a quaternary alloy of ruthenium-palladium-iridium-rhenium, where the alloy comprises 90 atom% of ruthenium and 1.5 atom% of palladium, iridium and rhenium. The catholyte further comprises a Bronsted acid comprising sulfuric acid, sodium hydrogen sulfate, potassium hydrogen sulfate, and ammonium hydrogen sulfate, and a carboxylic acid, preferably acetic acid, malonic acid, benzoic acid, and phthalic acid. Preferred Method: The ruthenium electroplating bath is obtained from an aqueous solution of ruthenium(III)-chloride and sulfamic acid by heating at the boil. The electroplating bath for metals of the platinum group is obtained from an aqueous solution of sulfamic acid, and a metal salt or metal complex comprising palladium chloride, potassium hexachloroiridate(IV), potassium hexachloroosmate(IV), rhodium sulfate, and diamino dinitrito platinum by heating. The electroplating bath for ruthenium alloys further comprises a rhenium electroplating bath comprising an alkali perrhenate or ammonium perrhenate, and sulfuric acid. EXAMPLE - Ruthenium(III) chloride (314.5 mg) was dissolved in deionized water (70 ml). A solution prepared by dissolving palladium(II) chloride (5.8 mg) in deionized water (3.42 ml) and 25% ammonia solution (0.1 ml) by stirring and heating and a solution of potassium hexachloroiridate(IV) (14.1 mg) in deionized water (6.19 ml) were added. The solution was cooled with an ice bath to 5 degrees C. Sodium borohydride (0.23 g) was dissolved in deionized water (9.04 ml) and the solution was added dropwise by a dropping funnel under stirring within 30 minutes while the temperature of the ruthenium-palladium-iridium salt solution was kept at 6-8 degrees C. Hydrogen was evolved and ruthenium-palladium-iridium black was formed. The solution was stirred for 12 hours, filtered through a sintered glass disc filter funnel and the resulting electro catalyst was washed with deionized water, absolute ethanol and absolute ether.