Room‐Temperature Synthesis of Amorphous Fe‐Doped Nickel Phosphate for High‐Efficiency Alkaline Seawater Oxidation

The construction of an efficient and durable oxygen evolution reaction (OER) electrocatalyst through a simple synthesis strategy is crucial for the hydrogen produced from seawater splitting. However, achieving this goal remains a great challenge. Herein, the synthesis of amorphous Fe-doped nickel phosphate (Fe-NixPO4) as a high-performance OER electrocatalysts for alkaline freshwater/seawater splitting is presented using a straightforward co-precipitation method at room-temperature. Experimental results reveal the structural reconstruction of Fe-NixPO4 into Fe-doped NiOOH decorated with PO4 3-. The collaborative interplay between Ni2+ and Fe3+, along with the decoration of PO4 3-, can effectively modulate the electronic environment of the electrocatalyst. Consequently, the optimized Fe-NixPO4 exhibits exceptional OER activity, requiring overpotentials of 359 and 422 mV to generate 1000 mA cm-2 in alkaline freshwater and alkaline seawater, respectively. Moreover, Fe-NixPO4 also displays outstanding stability for 100 h at 100 mA cm-2 in alkaline seawater. This research presents a viable approach for fabricating OER electrocatalysts with exceptional efficiency for seawater electrolysis.