Well-designed cobalt-nickel sulfide microspheres with unique peapod-like structure for overall water splitting.

Achieving sustainable energy technology with outstanding performance and clean materials for overall water splitting, while fascinating, still include many challenges. Herein, the masterly CoNi2S4@CoS2/NF 3D microspheres assembled by peapod-like nanorods with a mass of CoS2 particles are successfully prepared on nickel foam. The well-preserved 3D porous materials with unique heterostructure have various merits including more electronic channels, small electrons transfer resistance and open interior space. Besides, the unique peapod-like structure endows the catalyst plentiful, dispersive and exposed reactive sites, which is vital important to significantly increase the electrochemical performance. Notably, the as-prepared CoNi2S4@CoS2/NF catalysts achieve optimized electrocatalytic activity for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) at low overpotentials of 259 mV and 173 mV while deliver 10 mA cm-2 current density, respectively. It can be anticipated that it is a potential alternative catalyst for rational utilization in electrolytic water splitting fields.