A robust octahedral NiCoOxSy core-shell structure decorated with NiWO4 nanoparticles for enhanced electrocatalytic hydrogen evolution reaction

Electrocatalytic hydrogen evolution reaction by water splitting is deemed to a clean and efficient approach for greener energy. The intensive pursuit of cost-effective and stable electrocatalysts for HER is quite imperative and challenging. Herein, a typical core-shell NiWO4@NiCoOxSy/NCF nano-architecture consisted of NiCoOxSy/NCF octahedrons and NiWO4 nanoparticles on nickel-cobalt foam is synthesized, and the NiWO4@NiCoOxSy/NCF requires quite small overpotential of 85 mV to afford current density of 10 mA cm−2 for HER in 1 M KOH, respectively, while NiCoOxSy/NCF shows the overpotential of 132 mV at the current density of 10 mA cm−2 in 0.5 M H2SO4. Moreover, they still present good durability with continuous operation of 72 h in alkaline and acidic electrolytes, outperforming most of the non-noble bimetallic oxides or sulfides electrocatalysts. The prominent performance benefits from NiWO4@NiCoOxSy/NCF takes advantages of component respective strengths such as interfacial cooperative effect, strong electrical connection and fast electron transfer, the highly exposed surface area, in situ surface reconstruction. The work provides a new prospect toward the controlled design and rational fabrication of multicomponent hierarchical core-shell structure electrocatalyst in high-performance flexible electrochemical hydrogen production.