Highly active and durable cauliflower-like NiCo2O4 film for oxygen evolution with electrodeposited SiO2 as template

The sluggish kinetics of oxygen evolution reaction (OER) is the most challenging technical problem in water splitting. Here, we reported a new type of cauliflower-like NiCo₂O₄ (CF-NiCo₂O₄) film which was co-electrodeposited with silica for oxygen evolution reaction. Structure and morphology of the obtained films were characterized using X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Electrochemical properties of the CF-NiCo₂O₄ film were evaluated by quasi-steady state polarization curve, cyclic voltammetry and electrochemical impedance spectroscopy. Results show that the enhanced electrocatalytic activity of the CF-NiCo₂O₄ film toward OER is a synergistic effect of improved intrinsic catalytic activity and increased surface area.