TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The method comprises (a) synthesizing catalyst precursor of metal carbonyl cluster by weighing compound containing platinum or weighing a compound containing platinum and compound containing ruthenium, dissolving the compound in at least one of the following solvents: methanol, ethanol or acetone, and obtaining a solution containing metal ion, then adding an alkaline substance into the solution containing metal ion, and controlling the pH of the solution to 7.5-14 to obtain an alkaline solution system, then passing inert gas and/or carbon monoxide gas to remove the air in the alkaline solution system, and reacting for 20 minutes to 36 hours at room temperature of 80 degrees C in presence of inert gas and/or carbon monoxide gas to obtain the metal carbonyl cluster compound solution A; (b) injecting into magnesium oxide carrier by adding magnesium oxide into the metal carbonyl cluster compound solution A in presence of inert gas and/or carbon monoxide gas, stirring for a certain period of time at 0-80 degrees C, and then removing the solvent at 30-100 degrees C in presence of inert gas and/or carbon monoxide gas, and obtaining component B; (iii) subjecting the intermediate catalyst to heating treatment by treating the component B for 1-10 hours at 30-300 degrees C in presence of hydrogen gas and/or inert gas, washing with water, and drying to obtain component C; (d) dissolving magnesium oxide by adding a suitable amount of 0.05-2 M acid solution into the component C, stirring for 1-10 hours, washing with water, and drying to obtain platinum black nano electro-catalyst component D or platinum ruthenium black nano electro-catalyst component D; and (e) carrying out post-treatment of the catalyst by heat treating the component D at 50-300 degrees C in presence of inert gas, hydrogen gas and/or carbon monoxide gas, and obtaining the product whose particle size is 2-20 nm. Preferred Components: In the step (a), the compound containing platinum is chosen from a group containing chlorides and nitrates, and the compound containing ruthenium is chosen from a group containing chloride. The chloride containing platinum is sodium hexachloroplatinate(IV) hexahydrate. The nitrate containing platinum is platinum(II) nitrate, and the chloride containing ruthenium is ruthenium(III) chloride. In the step (a) the molar ratio of the platinum in the compound containing platinum to the ruthenium in the compound containing ruthenium is 1:0.1-1.5, when weighing a suitable amount of compound containing platinum and compound containing ruthenium. In the step (a), the alkaline substance is sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium acetate or an organic amine. In the step (b), the mass of magnetism oxide is 0.5-10 times the mass of platinum in the compound containing platinum. In the step (d), the molar ratio of acid solution added to magnetism oxide is 1-3:1. In the steps (a), (b), (c) and (e), the inert gas is nitrogen or argon. In the step (d), the acid is sulfuric acid, hydrochloric acid, nitric acid or acetic acid. In the step (e), the particle size of the obtained platinum black nano electro-catalyst and platinum ruthenium black nano electro-catalyst is 2-5 nm.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: In the step (a), the organic amine is ethylenediamine or pyridine.