Core-shell Ni3Fe-based nanocomposites for the oxygen evolution reaction

To deal with energy and environmental issues, it is necessary to exploit efficient and stable electrocatalysts for the generation of clean hydrogen. Herein, we describe the synthesis of bimetallic Fe/Ni alloy encapsulated by amorphous carbon shells via a facile annealing strategy for electrocatalytic oxygen evolution reaction (OER). The ferric nickel tartrate annealed at 800 °C (Ni 3 Fe 1 O x @C-800) exhibits a low OER overpotential of 264 mV at 10 mA cm −2 and good stability in alkaline media. Compared with monometallic counterpart, bimetallic Ni 3 Fe-based nanocomposites show lower OER barrier (ca. 324 kJ mol −1 ) due to a cooperation mechanism between Ni and Fe sites in promoting electrocatalytic water oxidation. Compared with those annealed at other temperatures, the enhanced OER performance of Ni 3 Fe 1 O x @C-800 can be ascribed to the large electrochemical surface area for exposing more active sites, smaller charge transfer, and better intrinsic activity of Ni 3 Fe-based sites. • Core-shell Ni 3 Fe 1 O x @C catalysts are fabricated by an annealing method. • Ni 3 Fe 1 O x @C-800 exhibits an overpotential of only 264 mV at 10 mA cm −2 . • Bimetallic Ni 3 Fe 1 O x @C-800 show lower OER barrier than monometallic counterpart. • The charge transfer ability can be enhanced by the core-shell structure. • The large ECSA of Ni 3 Fe 1 O x @C-800 favors exposing more active sites.