Coordination‐Mediated Heterogeneous Nucleation Enables Self‐Supported Ni(OH) ₂ /NiFe‐LDH Electrodes for AEM Water Electrolysis

ABSTRACT Self‐supported electrodes represent a promising anode architecture for anion exchange membrane water electrolyzers; however, their practical implementation is hindered by an insufficient understanding of their formation mechanisms and the consequently limited catalytic efficiency and stability. In this work, we developed a self‐supported electrode comprising a composite catalyst of β‐Ni(OH) ₂ and NiFe layered double hydroxide (LDH), grown on nickel felt (denoted as Ni(OH) ₂ /NiFe‐LDH/NFt) via a one‐step hydrothermal process. We systematically investigated and clarified the role of NH ₄ F in governing the synthesis of self‐supported Ni(OH) ₂ /NiFe‐LDH/NFt. The coordination effect of F ⁻ with Fe ³⁺ and etching effect of NH ₄ ⁺ on the surface oxide layer of nickel felt leads to favorable heterogeneous nucleation. Moreover, the etching effect provides an additional Ni source that favors the deposition of Ni(OH) ₂ on NiFe‐LDH. However, excess NH ₄ ⁺ leads to the formation of Ni‐based complex compounds in solution during the hydrothermal process and suppresses the deposition of Ni(OH) _2. When applying as the Ni(OH) ₂ /NiFe‐LDH/NFt anode catalyst in practical anion exchange membrane water electrolysis, it requires only 1.81 V to deliver 1.0 A cm ⁻² and exhibits outstanding durability, with no noticeable performance decay after 750 h of continuous operation at 0.5 A cm ⁻² .