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 (Ni₂P) nanosheet arrays supported on nickel foam (Ni1.85Fe0.15P NSAs/NF) are fabricated through a facile hydrothermal method, followed by phosphorization. The electrochemical analysis demonstrates that the Ni1.85Fe0.15P NSAs/NF electrode possesses high electrocatalytic activity for water splitting. In 1.0 M KOH, the Ni1.85Fe0.15P NSAs/NF electrode only needs overpotentials of 106 mV at 10 mA cm⁻² and 270 mV at 20 mA cm⁻² to drive the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Furthermore, the assembled two-electrode (Ni1.85Fe0.15P NSAs/NF∥Ni1.85Fe0.15P NSAs/NF) alkaline water electrolyzer can produce a current density of 10 mA cm⁻² at 1.61 V. Remarkably, it can maintain stable electrolysis over 20 h. Thus, this work undoubtedly offers a promising electrocatalyst for water splitting.