In the present work, we have accomplished morphology-controlled synthesis of ternary Pt-Pd-Cu alloy nanoparticles, particularly for efficient electrocatalytic oxygen reduction reactions. By controlling over the degree of galvanic displacement at room temperature, we selectively introduced porous and hollow architectures into Pt-decorated Pd-Cu alloy nanoparticles. Porous morphology was accompanied with partially facilitated Pt substitution reaction while hollow shape was exclusively achieved when the galvanic reaction was coupled with additional pre-treatment process which could eventually make the following displacement reaction more facile. Not only the both porous and hollow Pt@PdCu/C catalysts exhibited enhanced ORR performances compared to commercial Pt/C, but also they displayed outstanding durability. In addition, we investigated the alloying effects between Pt and Pd-Cu composite and the presumable influences of lattice strain through preliminary theoretical calculation to account for the enhanced ORR efficiency and durability of the present catalysts. (C) 2015 Elsevier B.V. All rights reserved.