Sandwich-Structured Fe-Ni2P/MoSx/NF Bifunctional Electrocatalyst for Overall Water Splitting

Exploring cost-efficient, high-active bifunctional electrochemical catalysts with long-term stability are significant for green economy. Herein, a noble-metal-free sandwich-structured catalyst, prepared with facile hydrothermal method and phosphorization process, in which the amorphous MoSx serves as an intermediate layer between the Fe-doped Ni2P and Ni foam substrate (Fe-Ni2P/MoSx/NF) is reported. The obtained free-standing catalyst performs an enhanced electrochemical activity compared with Fe-Ni2P/NF and MoSx/NF. The Fe-Ni2P/MoSx/NF catalyst only requires overpotentials of 246 mV to achieve 10 mA cm(-2) and 277 mV to reach 50 mA cm(-2) for oxygen evolution reaction process with a low Tafel slope of 59.7 mV dec(-1) in alkaline solution. Meanwhile, an overpotential of 112 mV is demanded to reach 10 mA cm(-2) for hydrogen evolution reaction. When the Fe-Ni2P/MoSx/NF is used as two electrodes for overall water splitting, it requires 1.61 V to attain 10 mA cm(-2) with prominent durability. This approach provides a versatile strategy to construct excellent bifunctional catalysts for effective water electrolysis.