Method for producing fine catalyst particles, method for producing carbon-supported fine catalyst particles, method for producing catalyst mix and method for producing electrode

A method for producing carbon-supported fine catalyst particles each comprising a core particle and an outermost layer, the core particle containing palladium and the outermost layer containing platinum and covering the core particle,

• the method comprising the steps of:
• preparing palladium-containing particles each supported by a carbon carrier;
• preparing an acid solution configured to dissolve palladium more preferentially than platinum;
• covering each palladium-containing particle supported by the carbon carrier with an outermost layer containing platinum;
• and
• bringing the palladium-containing particles each supported by the carbon carrier and covered with the outermost layer into contact with the acid solution.

A method for producing an electrode comprising an electrocatalyst layer and a gas diffusion layer, the electrocatalyst layer comprising carbon-supported fine catalyst particles each comprising a core particle and an outermost layer, the core particle containing palladium and the outermost layer containing platinum and covering the core particle,

• the method comprising the steps of:
• preparing palladium-containing particles each supported by a carbon carrier;
• preparing an acid solution configured to dissolve palladium more preferentially than platinum;
• preparing a gas diffusion sheet;
• covering each palladium-containing particle supported by the carbon carrier with an outermost layer containing platinum;
• forming an electrocatalyst layer on the gas diffusion sheet, the electrocatalyst layer comprising the palladium-containing particles each supported by the carbon carrier and covered with the outermost layer;
• and
• bringing at least the electrocatalyst layer into contact with the acid solution.