Electrodeposition-initiated, self-catalyzed growth of 2D amorphous Fe-group metal–boron alloy mesoporous films

Two-dimensional mesoporous amorphous metallic films, particularly those based on earth-abundant Fe-group metals (Ni, Co, Fe), are highly promising for various applications due to their high surface area, structural isotropy, and abundant undercoordinated sites. However, synthesizing continuous Fe-group amorphous metallic films with well-defined mesoporosity under mild conditions remains a challenge. Here, we develop an electrodeposition-initiated, self-catalyzed electroless growth strategy, enabling the synthesis of composition-tunable (from binary to quaternary) amorphous Fe-group metal–boron (M–B) mesoporous films (MFs) on various conductive substrates. This approach decouples the nucleation and growth stages, allowing precise control over film thickness, composition, and mesostructure. Thickness-time measurements suggest a self-accelerating growth process, whereas finite-element simulations indicate that substrate-dependent electric-field distributions modulate the nucleation and growth morphology. The synthesized multimetallic amorphous Ni–Co–Fe–B MF demonstrates high oxygen evolution performance and durability in alkaline simulated seawater, making them promising candidates for practical applications. Theoretical insights reveal preferential OH− adsorption over Cl− in the amorphous architecture, which may help mitigate chloride adsorption and facilitate the key reaction step. This study provides a method for synthesizing noble-metal-free amorphous M–B MFs. The authors developed a novel electrodeposition-initiated, self-catalyzed strategy to synthesize 2D amorphous metal-boron mesoporous films. This provides highly efficient and durable catalysts for the oxygen evolution reaction.