Bimetallic Iron and Nickel Nanoparticles for the Electrocatalytic Oxidation of Methanol and Ethanol for Fuel Cells

The electrochemical oxidation of alternative fuels, such as methanol and ethanol, for alkaline fuel cells often relies on the use of precious metal catalysts. However, the scarcity and high cost of these Pt group metals (Pt, Pd, Au, etc.) leads to the search for earth-abundant alternatives with similar electrocatalytic properties. Among these, iron emerges as a promising candidate as it has already been shown to have high activity for a variety of reactions. However, the rapid formation of oxides severely limits the stability of the iron nanoparticles. The addition of a second metal, such as nickel, slows this oxidation and can also enhance catalytic activity of the nanoparticles. In this work, bimetallic iron-nickel nanoparticles are synthesized in aqueous conditions at room temperature and pressure. Slight changes in the synthesis leads to significant differences in the size, stability, and lifetime of the nanoparticles. Possible explanations for these differences are characterized through both ex situ and in situ experiments. During electrochemical measurements, these materials show two distinct regions where redox reactions are taking place, which may correspond to nickel and iron reacting separately. The effects of various testing parameters on the electrochemical behavior are also explored.