Interfacial charge relay and dynamic electronic replenishment by a graphdiyne armor for stable RuO ₂ -based water electrolyser

Conventional powdery RuO₂ anodes for proton exchange membrane water electrolysis (PEMWE) suffer from sluggish interfacial charge transport and severe structural degradation. We propose porous graphdiyne (GDY) as a multifunctional coating on the self-supporting RuO₂-based electrode, creating a GDY@RuO₂ heterostructure to address the above interfacial issues and activity-stability trade-offs. Simulations study reveals that GDY induces interfacial directional charge transfer through sp-C-Ru bonds, modifying electronic structure, impeding O/Ru vacancy formation, and shifting OER pathway to the adsorbate evolution mechanism (AEM). Guided by these, RuO_2-x nanoparticles were deposited on titanium mesh, followed by controlled in-situ GDY growth. The optimized medium-thickness coating (GDY_M@RuO_2-x) exhibits exceptional performance: an overpotential of 196 mV at 10 mA cm^-2 in 0.5 M H₂SO₄, negligible voltage decay (0.046 mV h^-1) over 500 h operation, and a remarkable S-number. Due to the improved interfacial ohmic and charge transfer resistance between electrode-plate/PEM, the PEMWE using GDY armored anode can achieve 1 A cm^-2 at 1.55 V and stable operation at 0.5 A cm^-2 for 500 h (0.17 mV h^-1). Comprehensive analyses confirm the GDY efficacy of robust physical protection and its dynamic electron replenishment, optimizing Ru/O electronic structure to direct OER following AEM, reinforcing the RuO_2-x structure integrity.