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.