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

Abstract 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 MoS x serves as an intermediate layer between the Fe‐doped Ni 2 P and Ni foam substrate (Fe‐Ni 2 P/MoS x /NF) is reported. The obtained free‐standing catalyst performs an enhanced electrochemical activity compared with Fe‐Ni 2 P/NF and MoS x /NF. The Fe‐Ni 2 P/MoS x /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‐Ni 2 P/MoS x /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.