Low Ni-doped Co₃O₄ porous nanoplates for enhanced hydrogen and oxygen evolution reaction

In this paper, low Ni-doped Co₃O₄ (Ni: 2 wt%, 4 wt%, 6 wt% and 8 wt%) porous nanoplates are synthesized by hydrothermal method and annealing treatment. For the low Ni-doped Co₃O₄, X-ray diffraction (XRD) and Raman data show that the Ni ions are successfully incorporated into the Co₃O₄ lattices. Electrochemical measurements indicate that Co₃O₄ with low amount of Ni doping possesses remarkably enhanced activity for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media. And especially, 4 wt% Ni-doped Co₃O₄ possesses the most efficient activity with an overpotential of 240 mV at the current density of 10 mA cm⁻² for OER and 120 mV for HER in 1 M KOH than the pure Co₃O₄ and other Ni-doped Co₃O₄ samples. Our study suggests that the low doping would have a great potential in rational design of spinel oxides toward highly efficient electrocatalysis.