Ultra-thin wrinkled NiOOH–NiCr 2 O 4 nanosheets on Ni foam: an advanced catalytic electrode for oxygen evolution reaction

Here, we report the in situ electrochemical conversion of NiCr2O4 on Ni foam prepared using a hydrothermal strategy to give ultra-thin wrinkled NiOOH-NiCr2O4 amorphous-crystalline nanosheets on Ni foam (NiOOH-NiCr2O4/NF) via anode oxidation in 1.0 M KOH. Owing to the coordination of NiCr2O4 and NiOOH, NiOOH-NiCr2O4/NF shows superior catalytic activity toward the oxygen evolution reaction (OER) with the demand of overpotential as low as 271 mV to drive a geometrical current density of 20 mA cm-2 under alkaline conditions. Notably, it also displays strong long-term electrochemical durability for at least 30 h.