Fabrication of ultra-stable and high-efficient CoP-based electrode toward seawater splitting at industrial-grade current density

A novel strategy by one-step mild electroless plating is proposed to fabricate a Co–P@NN self-supporting electrode with high catalytic activity, conductivity, ultrastability for overall water splitting and catalyzing durability for over 2880h at an ultrahigh current density (>500 mA cm−2) in simulated seawater (1.0 M KOH + 0.5 M NaCl), high salt (1.0 M KOH + 3.0 M NaCl) and other harsh environments. [Display omitted] •Bifunctional ultra-stable Co–P self-supporting catalytic electrode is constructed by one-step mild electroless plating.•The synergism between Co–P@Co-O effectively adjusts the electron density to improve the intrinsic activity.•Co–P@NN shows excellent activity and ultra-stable in seawater or other harsh systems at industrial-grade current density. The mild and rapid construction of economical, efficient and ultrastable electrodes for hydrogen production via water splitting at industrial-grade current density remains extremely challenging. Herein, a one-step mild electroless plating method is proposed to deposit cobalt phosphorus (CoP)-based species on robust nickel net (NN, denoted as Co–P@NN). The tight interfacial contact, corrosion-proof self-supporting substrate and synergistic effect of Co–P@Co-O contribute greatly to the rapid electron transport, high intrinsic activity and long-term durability in the alkaline simulated seawater (1.0 M KOH + 0.5 M NaCl). Attractively, Co–P@Co-O also achieves ultrastable catalysis for over 2880 h with negligible activity attenuation under various alkaline extreme conditions (simulated seawater, high-salt environment, domestic sewage and so on). Furthermore, this work successfully constructs a series of ternary elemental doped (Ni, S, B, Fe and so on) CoP-based catalytic electrodes for highly efficient overall seawater splitting (OSWS). This work demonstrates not only an ideal platform for the versatile strategy of mildly obtaining CoP-based electrocatalysts but also the pioneering philosophy of large-scale hydrogen production.