Highly stable Pt₃Ni ultralong nanowires tailored with trace Mo for the ethanol oxidation

Pt₃Ni alloy structure is an effective strategy to accelerate ethanol oxidation reaction (EOR), while the stability in acid electrolyte is the fatal weakness and the current density still needs to be enhanced. Herein, ultralong Pt₃Ni nanowires tailored by trace Mo (Mo/Pt₃Ni NWs) were successfully synthesized by surfactant free method. The specific activity of the optimized catalyst was 2.66 mA·cm^–2, which is approximately 2.16 and 4.6-fold that of Pt₃Ni NWs and commercial Pt/C catalyst, respectively. Most importantly, the Mo/Pt₃Ni NWs catalyst showed negligible structure degradation after 3,000 cycles (42 h) of durability test in 0.1 M HClO₄ and 0.5 M ethanol, as compared to severe structural collapse and Ni dissolution for the pure Pt₃Ni NWs. The density functional theory (DFT) calculation also confirmed that both the surface and subsurface Mo atom could form Pt-Mo and Ni-Mo bonds with Pt and Ni, which were stronger than Pt-Ni bonds, to pin the Ni atoms in the unstable position and suppress the dissolution of surface Ni. The findings of this study indicate a promising pathway for the design and engineering of durable alloy nanocatalysts for direct ethanol fuel cell applications.