g-C3N4-Mediated Synthesis of Ru Crystalline/Amorphous Heterostructures on N-Doped Carbon for Efficient and Chloride-Resistant Alkaline HER

초록

Developing Pt-alternative electrocatalysts for the hydrogen evolution reaction (HER) requires balancing activity, stability, and corrosion resistance. Herein, a g-C3N4-mediated pyrolysis strategy is reported to construct nitrogen-doped carbon-anchored Ru nanoparticles with a crystalline/amorphous heterostructure (a/c-Ru@NC). During pyrolysis, g-C3N4 coordinates Ru3+ ions via N-sites and releases reductive gases for in situ reduction. Strong Ru─N bonding disrupts the atomic ordering in the core, forming amorphous Ru (a-Ru). Under the reductive atmosphere, the outer region further crystallizes into the crystalline phase (c-Ru) while the amorphous core remains preserved, thereby creating a phase-junction structure. The resulting catalyst exhibits ultrahigh dispersion (≈2.27 nm particles, 1 wt.% Ru loading) with optimized electronic properties. In 1.0 m KOH, a/c-Ru@NC achieves a low overpotential of 15 mV at 10 mA cm−2, a highly competitive mass activity of 24.312 A mgRu−1 (37 × higher than Pt/C), and negligible decay after 250 h operation. Crucially, it demonstrates exceptional chloride-corrosion resistance, showing only 8 mV overpotential increase from 0 m to saturated NaCl in electrolyte, much lower than that of commercial Ru/C (44 mV) and Pt/C (23 mV). This work provides a heterostructure design paradigm for sustainable hydrogen production in saline environments.

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