Three-Dimensional Strawlike MoSe₂-Ni(Fe)Se Electrocatalysts for Overall Water Splitting

The development of efficient and low-cost transition-metal electrocatalysts is of great significance for hydrogen production from water splitting. Herein, we synthesized three-dimensional strawlike MoSe₂-NiSe composed of microrods on nickel foam (NF) by a one-step hydrothermal reaction. The as-prepared MoSe₂-NiSe/NF exhibited effective hydrogen evolution reaction (HER) activity (low overpotential of 79 mV at 10 mA cm^-2 and stability of 21 h in 1 M KOH), benefiting from the large electrochemically active area provided by strawlike structures, proper Se content, and synergistic effect of active phases. The enhanced oxygen evolution reaction (OER) activity (the low overpotential of 217 mV at 10 mA cm^-2 and maintaining stability for 47 h in 1 M KOH) was further observed for Fe-doped MoSe₂-NiSe/NF (MoSe₂-NiFeSe/NF) prepared by facile soaking, which can be mainly ascribed to optimized active phases formed on the OER process after Fe doping. The two-electrode system (MoSe₂-NiSe/NF||MoSe₂-NiFeSe/NF) requires a low cell voltage of 1.54 V to obtain a current density of 10 mA cm^-2 in 1 M KOH, which provides an interesting idea for constructing an effective overall water splitting system.