Synthesis of intermetallic L10-Fe40Ni5M5Pt50 (M = Mn, Co, Cu) nanoparticles for electrocatalytic methanol oxidation†

Developing a highly efficient methanol oxidation electrocatalyst is crucial for enhancing the performance of direct methanol fuel cells. In this study, intermetallic L1₀-Fe₄₀Ni₅M₅Pt₅₀ (M = Mn, Co, Cu) nanoparticles with sizes ranging from 4 to 8 nm were synthesized by a facile solid-state reaction method. Replacing Fe with Mn, Co or Cu in L1₀-Fe₄₅Ni₅Pt₅₀ nanoparticles could increase grain size, facilitate the disorder-order transition, enhance electron transfer between Pt and Fe, and regulate the d-band centre. Notably, the L1₀-Fe₄₀Ni₅Co₅Pt₅₀ nanoparticles presented a higher ordering degree and a closer d-band centre to Pt, which contributed to superior electrocatalytic methanol oxidation properties. In comparison to commercial Pt/C catalysts, the L1₀-Fe₄₀Ni₅M₅Pt₅₀ nanoparticles demonstrated a 2.70-fold enhancement in mass activity, a 3.94-fold enhancement in area activity, and significantly improved stability. This study presents a promising strategy for synthesizing multicomponent, small-sized and highly ordered Pt-based intermetallic nanoparticle electrocatalysts.