In situ fabrication of sporoid-like flexible electrodes via Fe-regulated electron density for highly efficient and ultra-stable overall seawater splitting.

Construction of ultra-stable, flexible, efficient and economical catalytic electrodes is of great significance for the seawater electrolysis for hydrogen production. This work is grounded in a one-step mild electroless plating method to construct industrial-grade super-stable overall water splitting (OWS) catalytic electrodes (Fe-NiP@GF) by growing loose and porous spore-like Fe-NiP conductive catalysts in situ on flexible glass fibre (GF) insulating substrates with precise elemental regulation. Cost-effective Fe regulation boosts the electronic conductivity and charge transfer ability to achieve the construction of high intrinsic activity and strong electron density electrodes. Fe-NiP@GF exhibits remarkable catalytic performance in hydrogen and oxygen evolution reaction (HER and OER), providing current densities of 10 mA cm for HER and 100 mA cm for OER at overpotentials of 51 and 216 mV, respectively. Moreover, it achieves 10 mA cm at 1.42 V for OWS, and exhibits stable operation for over 1440 h at 1000 mA cm in quasi-industrial environment of 6.0 M KOH + 0.5 M NaCl, without any performance degradation. This strategy enables the preparation of universally applicable P-based electrodes (ternary, quaternary, etc.) and large-area flexible electrodes (paper or cotton), significantly expands the practicality of the electrodes and demonstrating promising potential for industrial applications.