Cathode catalyst layer structure for membrane electrode of fuel cell and method for preparing same

A method for preparing a cathode catalyst layer structure for a membrane electrode assembly of a fuel cell, the method comprising:

• forming a cathode catalyst layer structure having at least a first catalyst layer formed from a first slurry and a second catalyst layer formed from a second slurry, the second catalyst layer configured to be positioned closer to a proton exchange membrane of the membrane electrode assembly than the first catalyst layer, wherein:
• a first average particle diameter of a first platinum catalyst in the first slurry is less than a second average particle diameter of a second platinum catalyst in the second slurry;
• a first specific surface area of a first carbon support in the first slurry is greater than or equal to 200 m2/g, and a second specific surface area of a second carbon support in the second slurry is less than or equal to 200 m2/g;
• a first ionomer to carbon (“I/C”) ratio in the first slurry is greater than 0.9, and a second I/C ratio in the second slurry is less than or equal to 0.9;
• and
• a first weight percentage of the first platinum catalyst in the first slurry is 40% or more by weight, based on a first total weight of the first carbon support and the first platinum catalyst, and a second weight percentage of the second platinum catalyst in the second slurry is 40% or less by weight, based on a second total weight of the second carbon support and the second platinum catalyst.