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

Fast preparation of Fe precisely regulated 3D dandelion spore-like Fe1-Ni1P@GF self-supported electrode by one-step mild electroless plating for efficient ultra-stable overall water splitting at ultra-high current density in harsh environments such as quasi-industrial conditions (6.0 M KOH + 0.5 M NaCl), high salt (1.0 M KOH + 3.0 M NaCl) and simulated domestic wastewater (1.0 M KOH + 0.5 M urea). [Display omitted] •Successful preparation of large-size, robust and stable Fe1-Ni1P@GF bifunctional catalytic electrodes with Fe element precisely regulated by one-step mild electroless plating on corrosion-resistant glass fiber surface.•The precise regulation of Fe improves the electronic conductivity and charge transfer capability, significantly reduces the overpotential, and promotes the generation of OER active materials.•Fe1-Ni1P@GF not only has excellent electrocatalytic activity, but also has long-term stability in extreme environments such as quasi-industrial conditions, simulated domestic wastewater and high salt. 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 (Fe1-Ni1P@GF) by growing loose and porous spore-like Fe1-Ni1P 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. Fe1-Ni1P@GF exhibits remarkable catalytic performance in hydrogen and oxygen evolution reaction (HER and OER), providing current densities of 10 mA cm−2 for HER and 100 mA cm−2 for OER at overpotentials of 51 and 216 mV, respectively. Moreover, it achieves 10 mA cm−2 at 1.42 V for OWS, and exhibits stable operation for over 1440 h at 1000 mA cm−2 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.