Hierarchical Nickel Cobalt Sulfide Nanosheet Arrays Supported on CuO/Cu Hybrid Foam as a Rational-Designed Core-Shell Dendrite Electrocatalyst for Efficient Oxygen Evolution Reaction

Designing highly efficient, stable and low-cost electrocatalysts for the oxygen evolution reaction (OER) plays a key role to produce hydrogen via the electrolytic water method. Herein, we report a facile and manageable approach to fabricate a 3D steady core-shell dendrite electrocatalysts with nickel cobalt sulfide porous nanosheet as an outer layer and CuO nanowire as inner core supported by Cu foam for OER. Benefiting from the advantages of this unique 3D core-shell structure that endows affluent active sites, abundant interfacial heterostructures, high-speed electron transport network and short diffusion path for releasing O2 bubbles, the electrocatalyst displays outstanding OER performance with low overpotential of only 240, 289, 309 mV at the current density of 10, 50, 100 mA cm-2, respectively, and high durability over 48 h at a current density of 50 mA cm-2 in alkaline media. The high properties of the synthesized 3D dendrite-like catalyst for OER pave the way for large-scale practical water electrolysis.