| 摘要 |
The present invention is to provide fine catalyst particles to which sulfate ions are less likely to be adsorbed, and a carbon-supported catalyst to which sulfate ions are less likely to be adsorbed. Disclosed is a method for producing fine catalyst particles comprising a fine palladium-containing particle and a platinum-containing outermost layer covering at least part of the fine palladium-containing particle, wherein the method comprises: a copper covering step of covering at least part of the fine palladium-containing particle with copper by preparing a second dispersion by mixing a first dispersion comprising fine palladium-containing particles being dispersed in an acid solution with a copper-containing solution, and applying a potential that is nobler than the oxidation reduction potential of copper to the fine palladium-containing particles in the second dispersion, and a platinum covering step of covering at least part of the fine palladium-containing particle with platinum by substituting the copper covering at least part of the fine palladium-containing particle with platinum by mixing the second dispersion and a platinum-containing solution after the copper covering step, with applying a constant potential that is in a range between a potential that is nobler than the oxidation reduction potential of copper and a potential that is less than the oxidation reduction potential of platinum, to the fine palladium-containing particles. |
