Core–shell NiSe2/NiFe PBA enables chloride-tolerant seawater electrolysis via surface reconstruction

The development of efficient and stable catalysts is key for alkaline water/seawater electrolysis. Herein, we report a cubic-structured NiFePBA@NiSe 2 catalyst. In 1 M KOH, it requires an overpotential of only 278 mV to reach 300 mA cm −2 with a Tafel slope of 33.5 mV dec −1 . It also shows outstanding oxygen evolution reaction (OER) performance in alkaline simulated seawater (1 M KOH + 0.5 M NaCl) and natural seawater (1 M KOH + seawater). Experimental and characterization results reveal that highly active Ni(Fe)OOH species form in situ on the catalyst surface during OER. The introduction of NiSe 2 not only facilitates electron transfer and phase transformation, but the resulting selenate (SeO 4 2− ) species effectively repel chloride ions, which is particularly beneficial for stable seawater electrolysis. Benefiting from these structural advantages, the catalyst exhibits remarkable stability of 1000 h at 500 mA cm −2 in alkaline seawater. Furthermore, two-electrode electrolyzer and membrane electrode assembly tests using this material as the anode in alkaline seawater confirm its practical application potential. This work provides a new route for designing high-performance bifunctional electrocatalysts based on interface engineering and surface reconstruction.