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.

Rhodium (Rh)-based catalysts have shown superior potential over platinum for the alkaline electrocatalytic hydrogen evolution reaction (HER). However, achieving high catalytic activity while minimizing Rh usage remains a significant challenge. Herein, we anchored 1.48 wt.% Rh clusters onto nickel-iron layered double hydroxides with cationic defects. The Rh clusters exhibit multiple highly reactive crystallographic facets, providing numerous active sites for catalytic reactions. The cationic vacancies facilitate efficient charge transfer between the Rh clusters and the support through Rh–O bonds, lowering the d-band center of Rh and optimizing hydrogen adsorption strength. Consequently, the synthesized catalyst demonstrates exceptional performance, achieving an ultra-low overpotential of 4 mV at 10 mA·cm⁻², surpassing all previously reported Rh-based catalysts. This work presents a promising strategy for designing cost-effective and highly efficient alkaline HER catalysts.

The fabrication of heterointerface materials with hierarchical morphologies more than two levels is a challenging yet promising approach to achieve optimal electrocatalyst for hydrogen evolution reaction (HER). Here, using a facile two-step method, we are able to prepare the Ni₂P/(Co,Ni)OOH heterointerface with a three-level hierarchy morphology. The multiple levels of hierarchy structures not only offer considerable area for active sites loading, but also facilitate the substance transportation, both beneficial for HER. Meanwhile, the strong charge transfer at the Ni₂P/(Co,Ni)OOH heterointerface eliminates the spin asymmetry and achieves the thermos-neutral adsorption of active H species. Moreover, the resulted Coulomb attraction stacks the two materials firmly, facilitating the stability. Density functional theory (DFT) and in-situ Raman measurements reveal the sufficient Ni atoms acting as the active sites. With these merits, the Ni₂P/(Co,Ni)OOH exhibits much better HER activity than the separate Ni₂P or (Co,Ni)OOH, affording a current density of 100 mA/cm² at an overpotential of 169 mV and a Tafel slope of 41 mV/dec, when tested in alkaline electrolyte. This work provides inspiration for optimizing the intrinsic HER activity utilizing multiple-level hierarchy structures.