The Ni Heteroatom‐Induced Electronic Structure Tailoring of Ultrastable Fe₃N@NCPs Nanosheets Electrocatalyst for Boosting Alkaline Seawater Electrolysis

Abstract The exploration of high‐efficiency electrocatalysts is becoming indispensable for the production of H₂ from electrochemcial seawater splitting. Herein, a feasible strategy is developed to realize the in situ encapsulation of Ni‐decorated Fe₃N into porous N‐doped carbon nanolayer, abbreviated as Ni_x‐Fe₃N@NCPs, by an association of wet‐impregnation treatment and thermal annealing. More concretely, the doping of Ni can initiate the synergistic effect to optimize the internal electronic structure, which strengthen the adsorption of intermediates and interface charge transfer. Meantime, the architecture of NCPs encapsulation nanolayer not only enhances the conductivity and the structural stability, but also effectively prevents Cl⁻ ions transport from poisoning of electrocatalytic active sites. On these grounds, the preferred Ni_0.10‐Fe₃N@NCPs electrocatalyst delivers the exceptional bifunctional electrocatalytic performance in electrolytic seawater. The corresponding HER and OER overpotentials to attain the current densities of 10, 100, and 500 mA cm⁻² are only required 47, 147, and 291 mV as well as 152, 249, and 312 mV, respectively. In addition, the Ni_0.10‐Fe₃N@NCPs electrocatalysts achieves an ultra‐low voltage of 1.80 V at 500 mA cm⁻² with ultralong lifespan of 1200 h in zero‐gap alkaline electrolyzer. This work provides a cutting‐edge scientific research exploration for the development of electrocatalyst for seawater electrolysis.