Nickel iron oxide electrocatalysts for electrochemical OER activity.

Nickel iron oxides with different molar ratios were successfully prepared by facile hydrothermal method. Prepared NiFeO, with ratios of Ni:Fe as [3:1], [1:1] and [1:3], samples are further analyzed by basic characterizations like X-ray diffraction, UV–Vis absorption photoluminescence and FT-IR spectra investigations. The bandgap of the NiFeO [3:1], NiFeO [1:1] and NiFeO [1:3] samples were calculated to be 2.96 eV, 2.74 eV and 2.22 eV correspondingly. The morphology exhibited by the NiFeO [3:1], NiFeO [1:1] samples is the combined nanoparticles and nanosheets with thick and thin layers. The reduced in size explored Fe ions incorporation and NiFeO [1:3] sample revealed small nanoparticles. The electrochemical activity was studied. CV, LSV, EIS and CA spectra were analyzed. The specific capacitance of NiFeO [3:1], NiFeO [1:1] and NiFeO [1:3] is 232, 264 and 290 F/g. The overpotential calculated is 240 mV, 200 mV and 174 mV @ 10 mA/ cm² for NiFeO [3:1], NiFeO [1:1] and NiFeO [1:3] with 232 mA/g, 320 mA/g and 352 mA/g current densities. Lower overpotential of NiFeO [1:3] helped to attain higher current density which gives the smaller resistance. This unique behavior is enhanced by addition of Fe ions in higher concentration. The NiFeO [1:3] electrocatalysts were subjected to run for 12 h and there is no decrease in its performance. The better morphology and higher active sites enabled by indulging of Fe ions in NiFeO [1:3] electrode will be the best candidate for upcoming future use with no deduction in its performance. [ABSTRACT FROM AUTHOR]