Fig. 3: Cation clustering in the RT-NiFe-LDH.

ABF and HAADF images (same scale bar) of the RT-NiFe-LDH (a) and HT-NiFe-LDH (b) samples. The insets of the HAADF images show the diffractogram (fast Fourier transform), showing spots derived from the local degree of crystallinity. (Bottom) EELS maps showing the Fe and Ni spatial distribution obtained from EEL spectrum imaging, along with a color overlay of the Fe and Ni maps of the respective samples. DFT structure calculations. RT-NiFe-LDH (110) surface (c) HT-NiFe-LDH (110) surface (d). Gibbs free energy diagram of OER steps in HT and RT NiFe-LDH (110) surface (U = 0 V, pH = 0, T = 273.15 K) (e). Linear sweep voltammetry at 5 mV s−1 in 1 M KOH over glassy carbon rotating disk electrode at RT and 1200 rpm in after 30 activation cycles (50 mV s−1) (f). In situ Raman spectra of NiFe LDHs on carbon paper under different applied potentials. RT-NiFe-LDH (g) HT-NiFe-LDH (h).