Architectural Engineering of Ru-NiCoP@CoSe ₂ via Bridge-Linking Strategy for Universal Water Splitting Electrocatalysis

As global energy resources become increasingly depleted, countries worldwide are exploring clean-energy alternatives to traditional fossil fuels. Hydrogen combustion produces only water vapor and heat, which makes it an ideal clean energy source. Consequently, electrocatalytic hydrogen production has garnered significant attention for its potential applications in the clean-energy sector. However, traditional precious-metal catalysts currently used commercially are prohibitively expensive, severely limiting hydrogen energy development. Thus, designing highly efficient and stable non-precious-metal catalysts has become critically important. In this study, a ruthenium-doped core–shell bifunctional electrode catalyst, denoted as Ru-NCP@CoSe 2 -150, was designed. This material consists of a nickel–cobalt-phosphorus composite as the core and cobalt diselenide (CoSe 2 ) as the shell; NCP represents a composite phosphide of NiP 2 and CoP 2, and 150 denotes a RuCl 3 doping level of 150 mg. The bridge-linking strategy involves constructing a continuous electronic transport pathway at the NCP/CoSe 2 interface using Ru heteroatoms to achieve continuous control over the electronic structure of the core–shell architecture. This catalyst exhibits remarkable bifunctional water splitting activity across multiple electrolytes. Specifically, in acidic conditions, the overpotentials for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were 245 and 318 mV at 100 and 50 mA cm –2, respectively; in KOH solution, the values were 241.7 mV at 150 mA cm –2 and 1431.3 mV at 200 mA cm –2 . In seawater electrolyte, at a current density of 200 mA cm –2, the overpotentials for HER and OER were 322.7 and 1457.3 mV, respectively. The excellent pH universality of Ru-NCP@CoSe 2 -150 stems from a ternary synergistic mechanism: the NCP core provides highly conductive electron transport pathways, the CoSe 2 shell offers abundant active sites and can be in situ restructured into a hydroxyl oxide active phase, while Ru doping optimizes H 2 O/H + adsorption behavior by regulating the interfacial electronic structure and stabilizes high-valent active species. The synergy of these three components enables highly efficient bifunctional catalysis across a wide pH range. Finally, the catalyst underwent 30 h cyclic stability testing in various electrolytes, demonstrating excellent stability, with the current density remaining essentially unchanged.