NiFe2O4–Ni3S2 nanorod array/Ni foam composite catalyst indirectly controlled by Fe3+ immersion for an efficient oxygen evolution reaction

A NiFe alloy was designed on nickel foam (NF) as a precursor using cathodic electrodeposition . NiFe 2 O 4 –Ni 3 S 2 nanorods (NRs) composite catalysts were prepared by Fe 3+ impregnation and further hydrothermal sulfuration methods. NiFe 2 O 4 –Ni 3 S 2 nanosheets (NSs) were also prepared by direct hydrothermal sulfuration of the NiFe alloy for comparison. Compared to the dense NS structure of the NiFe 2 O 4 –Ni 3 S 2 NSs/NF, the NiFe 2 O 4 –Ni 3 S 2 NRs/NF showed better oxygen evolution performance due to its unique weed-like NR array structure composed of additional oxygen evolution reaction (OER) active sites, with a strong electron interaction for Ni and Fe and the active sulfide synergistic effect with oxides . Therefore, Driving a current density of 10 mA cm −2 only requires an overpotential of 189 mV and the catalyst could provide 100 mA cm −2 continuously and be constant for more than 80 h in 1.0 M KOH. This experiment indicated that Fe 3+ immersion had an indirect regulating effect on the morphological growth of the catalyst, which provided a novel concept for designing better OER catalysts.