Facile synthesis of NiS2–MoS2 heterostructured nanoflowers for enhanced overall water splitting performance

Although MoS 2 materials are known as the efficient catalysts in acidic solution toward hydrogen evolution reaction, it remains a challenging issue for improving catalytic activity of MoS 2 materials toward electrochemical splitting of water in alkaline solution. Herein, we developed NiS 2 –MoS 2 heterostructured nanoflowers with 430–810 nm in diameter using a simple one-pot hydrothermal method. The resultant catalysts required the potential of 1.5 V to afford 10 mA/cm 2 toward the oxygen evolution reaction, lower than that of MoS 2 nanoflowers. Hydrogen evolution reaction was enhanced by the introduction of Ni into MoS 2 nanoflowers with 194 mV at the current density of 10 mA/cm 2 . Moreover, the cell assembled by the NiS 2 –MoS 2 heterostructured nanoflowers could drive the voltage of 1.67 V at 10 mA/cm 2 using two-electrode system in 1.0 mol/L KOH solution toward overall water splitting. Structure-controlled synthesis of NiS 2 –MoS 2 nanoflowers, directing the construction of heterointerfaces with the exposure of the abundant active sites, greatly altered the electron distribution due to synergistic effect between Ni–S and Mo–S. Due to the unique structure, NiS 2 –MoS 2 heterostructured nanoflowers could effectively catalyze overall water splitting. Graphic abstract NiS 2 –MoS 2 heterostructured nanoflowers exhibited the enhanced overall water splitting activity in alkaline media due to more positive charges for Ni atoms and more surplus electrons for S.