▎ 摘　　要

NOVELTY - Synthesizing metal catalysts comprises supporting a transition metal on a support by mixing the support and the transition metal, heat-treating the support and the transition metal complex supported on the support to form a carbon shell on a surface, and oxidizing the surface of the transition metal complex by supplying oxygen in a cooling process of lowering the temperature after the heat treatment. USE - The metal catalyst is useful for fuel cell. ADVANTAGE - The metal catalyst: has controlled carbon shell thickness through surface oxidation; suppress the decrease in mass transfer due to the existence of the carbon shell; secures durability; minimizes the preparation time for driving the unit battery; improves mass transfer characteristics; and reduces activation time by maintaining durability.