Binary Fe−Co Alloy Nanoparticles Showing Significant Enhancement in Electrocatalytic Activity Compared with Bulk Alloys

Microemulsion-based synthesis of Fe−Co alloy nanoparticles has been reported for the first time. Spherical, uniform, and highly monodisperse nanoparticles of Fe 75 Co 25, Fe 67 Co 33, Fe 50 Co 50, and Fe 33 Co 67 with an average size of 20, 25, 10, and 40 nm, respectively, were synthesized. These nanoparticles crystallize in a body-centered cubic cell. A higher cobalt content led to the formation of biphasic mixtures. Energy-dispersive X-ray spectroscopy studies confirmed the Fe/Co ratios. Nanoparticles of the Fe 33 Co 67 alloy show higher hydrogen and oxygen evolution efficiencies (over 100 times) compared with other Fe−Co alloys of nanocrystalline or bulk form. The Fe−Co alloy nanoparticles also show ferromagnetism.