Plasma-enabled synthesis of ordered PtFe alloy nanoparticles encapsulated with ultrathin N-doped carbon shells for efficient methanol electrooxidation

Methanol oxidation reaction(MOR),the key reaction for clean energy generation in fuel cells,is kinetically sluggish and short-lasting because of insufficient catalytic activity and stability of the common Pt-based electrocatalysts.Ordered Pt alloy structures which promise to surmount these issues,are challenging and impractical to fabricate using common high-temperature annealing.To address the urgent need for simple and rapid synthesis methods for such alloys,here we report the versatile plasma-assisted thermal annealing synthesis of a robust electrocatalyst with PtFe alloys supported on N-doped carbon nanotubes(denoted as PtFe@NCNT-P).Benefiting from the reactive plasma-specific effects,the PtFe@NCNT-P electrocatalyst features ultrafine PtFe alloy nanoparticles(mean size~2.88 nm,ordered degree~87.07%)and ultrathin N-doped carbon(NC)shells(0.3–0.7 nm),leading to the excellent catalytic activity and stability toward MOR.The catalyst shows the specific and mass activities of 3.99 mA/cm^(2)and 2,148.5 mA/mg,which are 7.82 and 7.41 times higher than those for commercial Pt/C(0.51 mA/cm^(2),290 mA/mg),and 2.18 and 2.59 times higher compared to the plasma-untreated PtFe@NCNT(1.83 mA/cm2,829.5 mA/mg),respectively.The PtFe@NCNT-P further exhibits extraordinary stability during the long-term chronoamperometry test and 1,000-cycle cyclic voltammetry scanning,much better compared to PtFe@NCNT samples even after the longer thermal annealing.These findings show great potential of the plasma-enabled synthesis of high-performance carbon-supported metallic electrocatalysts for the emerging clean energy technologies.