Catalyst, a method of manufacturing a catalyst, a membrane electrode assembly and a fuel cell

A catalyst is provided and includes fine catalyst particles of a composition represented by formula (1): PtuRuxTayTz, in which T is at least one element selected from the group consisting of Hf, W, Ni, and V; u, x, y, and z are 10 to 98.9 atm %, 0.1 to 50 atm %, 0.5 to 35 atm %, and 0.5 to 35 atm %, respectively, or formula (2): PtuRuxTayTz, in which T is at least one element selected from the group consisting of Ct, Mo, Nb, Zr, and T; u, x, y, and z are 40 to 70 atm %, 0.1 to 50 atm %, 0.5 to 15 atm %, and 0.5 to 15 atm %, respectively.