Multimetallic AuPd@Pd@Pt core-interlayer-shell icosahedral electrocatalysts for highly efficient oxygen reduction reaction

Incorporating Pt with core metals into Pt-based core-shell catalysts is regarded as a promising strategy to substantially enhance the catalytic properties towards oxygen reduction reaction（ORR） in fuel cells due to the synergetic effect between distinct metals. In this wok, ultrathin Pt skins with two atomic layers were epitaxially coated on as-prepared icosahedral Au50Pd50, Au60Pd40 and Au66Pd34 nanocrystal seeds,which are constructed with alloyed cores and Pd shells with different thickness. Through electron microscopic characterizations, Pd interlayers with tunable thickness of 3, 6, and 12 atomic layers can be found in the Au66Pd34@Pt, Au60 Pd40@Pt and Au50Pd50@Pt icosahedra, respectively. These icosahedral Au Pd@Pd@Pt nanocrystals show substantially enhanced activities and durabilities in electrocatalytic measurements towards ORR compared to Au75Pd25@Pt icosahedra without Pd interlayer and commercial Pt/C catalysts. Specifically, Au60Pd40@Pt icosahedra with 6 atomically thick Pd interlayer display the best electrocatalytic performances, whose mass activities before and after durability tests of 50,000 cycles are11.6 and 30.2 times, respectively, as high as that of the commercial Pt/C.