Pd-based structurally ordered phase nanoparticles (NPs)/carbon black (CB) were successfully prepared by reduction of precursors of Pd and secondary materials using ethylene glycol as a reducing agent and an annealing procedure. In one of our studies, we developed structurally ordered intermetallic PdCu₃ which has Cu3Au type structure electrocatalysts with excellent ORR activity in acidic media. High electrocatalytic activity of ordered intermetallic PdCu₃ was inspired by electrochemically dealloy process. This electrochemical phenomenon on high catalytic activity was discussed by both density functional theory calculations and X-ray photoelectron spectroscopy. In this poster session, we have summarized our recent results.