Achieving highâefficiency and stable hydrogen evolution from water splitting is a great challenge. Herein, a facilely prepared twoâdimenssional selfâsupported catalytic electrode with excellent stability is constructed for largeâscale hydrogen production from alkaline simulated seawater. The bifunctional catalytic electrode is prepared by a fast and mild oneâstep of sodium borohydride etching on a nickel foam (NF) substrate without adding other additives (NF@NiBxâ3h). The overpotential of the hydrogen/oxygen evolution reaction (HER/OER) in alkalineâsimulated seawater at 10 mA cmâ2 is 96 mV and 261 mV. At 200 mA cmâ2, the NF@NiBxâ3h electrode shows good stability over 7 days throughout the water splitting process due to the corrosion resistance of the NF substrate, and strong adhesion between the NiâB active material and the substrate. This work demonstrates a novel strategy for fabricating catalytic electrodes with highâperformance, low cost and excellent stability.