Large-area, flexible bimetallic phosphorus-based electrodes for prolong-stable industrial grade overall seawater splitting

Series of large-area, flexible and highly efficient bifunctional electrodes were constructed in situ on hydrophilic filter paper by a one-step mild electroless plating method. The bifunctional NiCoP@HP electrode enabled ultra-stable overall water splitting in harsh environment (seawater and urea) for over 1440h at 0.5 A cm−2. [Display omitted] •Mildly constructed of large-area, flexible bimetallic phosphorus-based electrodes.•The Ni-Co alloying and the electronegative phosphorus-based material combine to enhanced intrinsic activity of NiCoP@HP.•NiCoP@HP achieved durable OWS over 1440 h at 500 mA cm-2 in 1.0M KOH+0.5M NaCl and 1.0M KOH+Seawater respectively. The economical and efficient preparation of highly stable electrodes for hydrogen from water splitting is one of the current challenges. Herein, a flexible and durable bifunctional nickel–cobalt-phosphide electrode is constructed in situ on hydrophilicity filter paper (NiCoP@HP) via a one-step mild electroless plating method for industrial-scale water splitting. The bimetallic synergy of Ni-Co facilitates efficient electron transfer, while the electronegativity of phosphide contributes to high intrinsic activity, and the flexible paper substrate allow the electrode to be folded and bent. The NiCoP@HP electrodes exhibit outstanding performance for the hydrogen/oxygen evolution reaction (HER/OER), with low overpotentials only 43 mV and 164 mV at a current density of 10 mA cm−2 in simulated seawater (1.0 M KOH + 0.5 M NaCl). Importantly, the NiCoP@HP electrode demonstrates long-term stability, operating for over 1440 h at a current density of 500 mA cm−2 in 1.0 M KOH + 0.5 M NaCl and 1.0 M KOH + Seawater, respectively. This universally applicable method allows the preparation of a range of highly efficient catalytic electrodes (Fe, Mo, W, etc.). This work provides a simple, scalable, and versatile approach for the in situ construction of noble metal-free, highly efficient, and cost-effective bifunctional electrocatalysts, opening new possibilities for industrial-scale water splitting.