Ruthenium phosphide electrocatalysts for the hydrogen evolution reaction (HER) still face challenges such as insufficient active site utilization and limited durability. This work addresses these challenges via a synergistic strategy that integrates heterojunction engineering with a hollow confinement structure, resulting in RuP₂-Ni₂P nanoparticles embedded within N,P-codoped hollow carbon spheres (RuP₂-Ni₂P/NPC). The interfacial coupling between RuP₂ and Ni₂P optimizes the electronic structure toward a near-ideal hydrogen adsorption energy, while the unique embedded architecture ensures abundant accessible active sites and exceptional structural robustness. As a result, the RuP₂-Ni₂P/NPC catalyst exhibits superior HER performance across a wide pH range, achieving ultralow overpotentials of 3 mV in 1 M KOH and 17.3 mV in 0.5 M H₂SO₄ at 10 mA·cm⁻², ranking among the best of reported RuP₂-based catalysts. It also demonstrates excellent long-term durability in both alkaline and acidic electrolytes. This work provides a feasible design strategy toward efficient and robust electrocatalysts for hydrogen production.

The industrial implementation of water electrolysis for hydrogen production is significantly hindered by the sluggish kinetics of the oxygen evolution reaction, while the high cost of state-of-the-art iridium-based catalysts remains a critical challenge. This work demonstrates an innovative heterojunction-doping synergy strategy through rational design of SrPd_3−xRu_xO₄/SrRuO₃ composite electrocatalysts. The strategy combines the structural advantages of cubic-phase SrPd₃O₄ and perovskite-type SrRuO₃, where their inherent compatibility facilitates atomic-level interface formation through oxygen-bridge coordination. Simultaneously, controlled Ru substitution in the SrPd₃O₄ lattice induces beneficial structural strain and precisely modulates the electronic environment to optimize intermediate adsorption energetics. The optimized catalyst exhibits exceptional electrocatalytic performance in 1 M KOH, delivering an overpotential as low as 227.6 mV at 10 mA·cm⁻² and notably retaining stability for 300 h at 50 mA·cm⁻². In situ Raman spectroscopy confirms the dominance of the adsorbate evolution mechanism, while theoretical calculations reveal that the synergistic effects diminish the activation energy barrier governing the rate-determining step. This work not only provides fundamental insights into the design of Pd-based oxide catalysts but also establishes a generalizable approach for developing high-performance electrocatalysts through synergistic structural engineering.