Ni0.85Se@CoFe LDH heterostructure nanosheet arrays on Ni foam as efficient electrocatalysts for enhanced oxygen evolution

Exploring high-efficient, earth-abundant and stable electrocatalyst for oxygen evolution reaction (OER) is of vital importance for large-scale implementation of energy converting and storing. Thus, we fabricated a free-standing hierarchical heterostructure electrode of Ni 0.85 Se@CoFe LDH/NF via a rational combination of hydrothermal, selenization and electrodeposition process, among which the ultrathin CoFe LDH nanosheets intimately assembled onto the vertical aligned Ni 0.85 Se nanosheets supported on Ni foam. The constructed core-shell nanosheet arrays hold the plentiful hetero-interfaces and intimate interactions through metal-oxygen bonds between two individuals, which guarantee the fast OER kinetic processes. Additionally, CoFe LDH with crystalline/amorphous hybrid structure favors providing more reaction sites. Remarkably, the optimal Ni 0.85 Se@CoFe LDH/NF binary composites possess outstanding OER activity with a low overpotential of ∼223 and 280 mV at 10 mA cm −2 and 100 mA cm −2 in alkaline solution as well as good durability. This research offers an alternative approach for improving electrocatalytic water splitting through constructing 3D hierarchical heterostructures.