3D V–Ni3S2@CoFe-LDH core-shell electrocatalysts for efficient water oxidation

Abstract

Studying cheap and efficient electrocatalysts is of great significance to promote the sluggish kinetics of oxygen evolution reaction (OER). Here, we adopted a simple two-step method to successfully prepare the 3D V–Ni3S2@CoFe-LDH core-shell electrocatalyst. The V–Ni3S2@CoFe-LDH/NF shows excellent OER performance with low overpotential (190 mV at 10 mA/cm2 and 240 mV at 50 mA/cm2), small Tafel slope (26.8 mV/dec) and good long-term durability. Excitingly, to reach the same current density, V–Ni3S2@CoFe-LDH/NF electrode even needs much smaller overpotential than RuO2. Furthermore, the outstanding OER activity of V–Ni3S2@CoFe-LDH/NF is ascribed to the following reasons: (1) V–Ni3S2 nanorod cores improve the conductivity and ensure the fast charge transfer; (2) CoFe-LDH nanosheets interconnected with each other provide more exposed active sites; (3) the unique 3D core-shell structures are favorable for electrolyte diffusion and gas releasing. Our work indicates that building 3D core-shell heterostructure will be a useful way to design good electrocatalysts.