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

Abstract 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‐Ni x PO 4 ) 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‐Ni x PO 4 into Fe‐doped NiOOH decorated with PO 4 3− . The collaborative interplay between Ni 2+ and Fe 3+ , along with the decoration of PO 4 3− , can effectively modulate the electronic environment of the electrocatalyst. Consequently, the optimized Fe‐Ni x PO 4 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‐Ni x PO 4 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.