Iron-Doped Nickel Phosphide Nanosheet Arrays: An Efficient Bifunctional Electrocatalyst for Water Splitting.

Exploring efficient and earth-abundant electrocatalysts for water splitting is crucial for various renewable energy technologies. In this work, iron (Fe)-doped nickel phosphide (NiP) nanosheet arrays supported on nickel foam (NiFeP NSAs/NF) are fabricated through a facile hydrothermal method, followed by phosphorization. The electrochemical analysis demonstrates that the NiFeP NSAs/NF electrode possesses high electrocatalytic activity for water splitting. In 1.0 M KOH, the NiFeP NSAs/NF electrode only needs overpotentials of 106 mV at 10 mA cm and 270 mV at 20 mA cm to drive the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Furthermore, the assembled two-electrode (NiFeP NSAs/NF∥NiFeP NSAs/NF) alkaline water electrolyzer can produce a current density of 10 mA cm at 1.61 V. Remarkably, it can maintain stable electrolysis over 20 h. Thus, this work undoubtedly offers a promising electrocatalyst for water splitting.