Electrode catalyst for fuel cell, electrode catalyst layer for fuel cell, method for producing the same, and membrane electrode assembly and fuel cell using the catalyst layer

An electrode catalyst for fuel cell comprising a catalyst carrier containing carbon as a main component and a catalytic metal carried on the catalyst carrier,

• wherein the catalyst has a ratio R′ (D′/G intensity ratio) of a peak intensity of D′ band (D′ intensity) measured in the vicinity of 1620 cm−1 to a peak intensity of G band (G intensity) measured in the vicinity of 1580 cm−1 by Raman spectroscopy of more than 0.6 and 0.8 or less, and satisfies at least one of the following (a) to (d):
• (a) the catalyst has pores with a radius of less than 1 nm and pores with a radius of 1 nm or more, a pore volume of the pores with a radius of less than 1 nm of 0.3 cc/g carrier or more, and the catalytic metal carried inside the pores with a radius of 1 nm or more;
• (b) the catalyst has pores with a radius of 1 nm or more and less than 5 nm, a pore volume of the pores of 0.8 cc/g carrier or more, a specific surface area of the catalytic metal of 60 m2/g carrier or less and the catalytic metal carried inside the pores with a radius of 1 nm or more;
• (c) the catalyst has pores with a radius of less than 1 nm and pores with a radius of 1 nm or more, a mode radius of pore distribution of the pores with a radius of less than 1 nm is 0.3 nm or more and less than 1 nm, and the catalytic metal is carried inside the pores with a radius of 1 nm or more;
• and
• (d) a mode radius of pore distribution of pores with a radius of 1 nm or more is 1 nm or more and less than 5 nm, the catalytic metal is carried inside the pores with a radius of 1 nm or more, the mode radius is half or less of an average particle size of the catalytic metal, and a pore volume of the pores with a radius of 1 nm or more is 0.4 cc/g carrier or more.