Fig. 5

Electrocatalytic OER performance in 1.0 M KOH electrolyte. a Voltammetry (scan rate 10 mV s⁻¹) of NiCeO _x H _y , Ni(OH)₂, CeO₂, and RuO₂ supported on rotational disk electrode with mass loading of 0.2 mg cm⁻². b Mass and specific activities derived from (a) at 1.5 V. The data of CeO₂/G are multiplied by 5 for clear display. c Polarization curves (scan rate 10 mV s⁻¹) of NiCeO _x H _y /G, Ni(OH)₂/G, and RuO₂/CP electrodes with mass loading of 10, 10, and 6 mg cm⁻², respectively. d Tafel plots derived from the curves in (c). e Chronopotentiometry of RuO₂/CP and NiCeO _x H _y /G at a current density of 1000 mA cm⁻². Inset shows the SEM images (scale bar: left 20 μm, right 200 nm) of the NiCeO _x H _y /G electrode after OER test at 1000 mA cm⁻² for 300 h