Nanocatalysts that boost the sluggish kinetics of oxygen reduction reaction with a long-term durability are crucial for widespread use of low-temperature fuel cells. Here we report a nanoporous intermetallic compound typically composed of platinum-cobalt-aluminum intermetallic core with in-situ grown atomic-layer-thick Pt skin as a novel oxygen-reduction-reaction nanocatalyst with remarkably enhanced performance. Both Pt and Co atoms thermodynamically prefer to locate nearby Al element within face-centered cubic Pt3Al matrix via the formation of strong Pt-Al and Co-Al bonds, which not only enable synergistic ligand and compressive strain effects to moderately weaken the oxygen adsorption energy of Pt skin, but alleviate the evolution of surface Pt atoms to protect against the further dissolution of less-noble Co and Al. As a result, the nanoporous platinum cobalt aluminum nanocatalyst exhibits specific activity of 3.40 mA cm(Pt)(-2) and mass activity of 2.2 A mg(Pt)(-1), for the oxygen reduction reaction at 0.9 V versus reversible hydrogen electrode (similar to 13- and similar to 20-fold enhancement relative to commercially available platinum nanoparticles supported carbon) with an exceptional durability, showing genuine potential as cathode catalyst in next-generation electrochemical energy conversion devices. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.