Bimetallic chloride in situ etching of NiFe alloy substrate to synthesize porous coral structure catalyst for efficient oxygen evolution reaction

Through morphological and valence control, a superhydrophilic/superaerophobic nanoporous coral-like catalytic material was grown on NiFe foam via in-situ etching of bimetallic chloride. The material exhibits excellent oxygen evolution reaction (OER) performance and stability during water splitting. • Porous coral structure offers abundant active sites & excellent superhydrophilic/ superaerophobic props. • Bimetallic chloride etching grew a stable catalyst in-situ. • Excellent catalytic activity with only 236 mV overpotential required at a current density of 10 mA cm −2 . • Excellent catalytic stability, operating stably for 100 h at 150 mA cm −2 without decay. • Crystal-amorphous synergy boosts OER catalytic efficiency. The development of efficient and energy-saving preparation processes for electrocatalytic water-splitting catalysts is crucial to advancing industrial hydrogen production. Among these, the research and development of anode oxygen evolution materials play an indispensable role. This study addresses the critical technical bottlenecks of oxygen evolution reaction (OER) materials in industrial water electrolysis by proposing a breakthrough solution. We innovatively designed a room-temperature dual-metal ion (NaCl-CrCl 3 ) dynamic etching strategy to construct chromium-doped nickel–iron hydroxide precursors on nickel–iron foam (NIF) in a single step. Through a low-temperature sulfurization process, we successfully synthesized a coral-like three-dimensional hierarchical porous Cr-Ni 3 S 2 @Fe x S y /NIF heterojunction catalyst. The material demonstrates record-low overpotential (236 mV@10 mA cm −2 ) and exceptional long-term stability (100 h@150 mA cm −2 ) in 1 M KOH electrolyte. Morphological and structural characterization reveals that the unique nano-coral architecture and electronic synergy endow the material with superhydrophilic/superaerophobic surface properties and highly efficient electrocatalytic OER performance. This work overcomes the limitations of traditional high-temperature preparation processes, offering a novel design paradigm for developing electrolysis catalysts that combine high activity with industrial-grade stability.