The　commercialization　of　proton　exchange　membrane　fuel　cells　(PEMFCs)　relies　on　highly　active　and　stable　electrocatalysts　for　oxygen　reduction　reaction　(ORR)　in　acid　media.　The　most　successful　catalysts　for　this　reaction　are　nanostructured　Pt-alloy　with　a　Pt-skin.　The　synthesis　of　ultrasmall　and　ordered　L1(0)-PtCo　nanoparticle　ORR　catalysts　further　doped　with　a　few　percent　of　metals　(W,　Ga,　Zn)　is　reported.　Compared　to　commercial　Pt/C　catalyst,　the　L1(0)-W-PtCo/C　catalyst　shows　significant　improvement　in　both　initial　activity　and　high-temperature　stability.　The　L1(0)-W-PtCo/C　catalyst　achieves　high　activity　and　stability　in　the　PEMFC　after　50　000　voltage　cycles　at　80　degrees　C,　which　is　superior　to　the　DOE　2020　targets.　EXAFS　analysis　and　density　functional　theory　calculations　reveal　that　W　doping　not　only　stabilizes　the　ordered　intermetallic　structure,　but　also　tunes　the　Pt-Pt　distances　in　such　a　way　to　optimize　the　binding　energy　between　Pt　and　O　intermediates　on　the　surface.