Radical scavenger, method for preparing same, and membrane-electrode assembly containing same

A radical scavenger capable of removing hydroxyl radicals generated during an operation of a fuel cell, the radical scavenger comprising:

• a radical-scavenging particle;
• and
• a porous protective film over a surface of the radical-scavenging particle,
• wherein the porous protective film comprises at least one material of high oxidative stability selected from the group consisting of silica, carbon nitride, heteroatom-doped graphene, a porphyrin-based compound, a phenazine-based compound and derivatives thereof,
• wherein the heteroatom is selected from the group consisting of N, S, P, B and F,
• wherein the radical-scavenging particle comprises Ce, a salt thereof, an oxide thereof, a nitride thereof, or a complex thereof,
• wherein the porous protective film has a thickness of 0.5 to 50 nm, and
• wherein an average pore diameter of the porous protective film is larger than 0.22 nm and smaller than 0.45 nm such that the porous protective film allows the hydroxyl radicals to pass therethrough but prevents Ce ions from passing therethrough.