Fig. 1. (a) CV of NiFe LDH loaded on nickel foam in 1 M KOH, and (b) resulting overpotential values (±7 mV) for OER as a function of cycle number, through 200 cycles. (c) Corresponding ex situ Raman spectra in the selected wavenumber range 200–800 cm⁻¹ for NiFe LDH on Ni foam, (from bottom) for the as-prepared catalyst, and after 5, 50 and 200 CV cycles between 1–1.6 V vs. RHE at 5 mV s⁻¹.