Fig. 3: Characterization and electrochemical performance of catalytic GC sheet.

a Tilted (45°) SEM micrograph of a GC sheet coated with Ni nanopyramids and NiFeOOH catalyst. b XRD diffractograms of bare GC sheet and GC/Ni sheet. c LSV plots (in the dark) of various functionalized GC sheets with Ni nanopyramids and NiFeOOH (solid lines) and linear extrapolation for OER onset potential determination (dashed lines). Electrolyte is aqueous 1 M NaOH (pH 14). 50 mV s−1 scan rate. d Electrochemical overpotential stability test at 10 mA cm−2 in 1 M NaOH (pH 14) on GC/Ni/NiFeOOH catalytic sheet.