Electronic structure modulation of Ru-NiCu bimetallic phosphide for highly efficient and stable overall water splitting in alkaline and seawater conditions.

To meet the urgent demand for low-cost and highly active electrocatalysts in water electrolysis for hydrogen production, a ruthenium-doped nickel-copper bimetallic phosphide electrocatalyst (Ru-NiCuP@NF) was successfully prepared. Electrochemical measurements reveal that in 1.0 M KOH electrolyte, the as-prepared Ru-NiCuP@NF catalyst requires only 108 mV for the hydrogen evolution reaction (HER) and 243 mV for the oxygen evolution reaction (OER) at a current density of 10 mA cm-2. This performance is attributed to the metal doping, which effectively modulates the electronic structure and provides robust water dissociation capability. In alkaline seawater, the overpotentials required to achieve 10 mA cm-2 are 120 mV for HER and 278 mV for OER. Furthermore, when assembled into a two-electrode overall water splitting system, a cell voltage of only 1.28 V is required to deliver a current density of 10 mA cm-2 in 1.0 M KOH.