Iron–Nickel Nanoparticles as Bifunctional Catalysts in Water Electrolysis

Abstract

Iron−nickel nanoparticles (Fe−Ni NPs) were successfully synthesized in various stoichiometries by using the inverse micelle method followed by combustion at 500 °C for 12 h in H2. Ni-rich Fe−Ni NPs crystallize in a face-centered cubic (fcc) structure, whereas Fe-rich Fe−Ni NPs stabilize in body-centered cubic (bcc) structure. Fe−Ni NPs operate as bifunctional electrode materials at room temperature in alkaline medium and show enhanced electrocatalytic activity in the electrolysis of water to H2 evolution and O2 evolution reactions (HER and OER) at low onset potential versus Ag/AgCl as the reference electrode. A low Tafel slope was also detected for Fe2Ni NPs (ca. 470 mV/dec) in the water oxidation reaction. Bifunctional electrocatalysts are significant in renewable and clean energy processes like hydrogen–oxygen fuel cells, metal–oxygen batteries, and so forth.