A Unique Ru-N₄-P Coordinated Structure Synergistically Waking Up the Nonmetal P Active Site for Hydrogen Production

Numerous experiments have demonstrated that the metal atom is the active center of monoatomic catalysts for hydrogen evolution reaction (HER), while the active sites of nonmetal doped atoms are often neglected. By combining theoretical prediction and experimental verification, we designed a unique ternary Ru-N₄-P coordination structure constructed by monodispersed Ru atoms supported on N,P dual-doped graphene for highly efficient hydrogen evolution in acid solution. The density functional theory calculations indicate that the charge polarization will lead to the most charge accumulation at P atoms, which results in a distinct nonmetallic P active sites with the moderate H∗ adsorption energy. Notably, these P atoms mainly supply highly efficient catalytic sites with ultrasmall absorption energy of 0.007 eV. Correspondingly, the Ru-N₄-P demonstrated outstanding HER performance not only in an acidic condition but also in alkaline environment. Notably, the performance of Ru-NPC catalyst at high current is even superior to the commercial Pt/C catalysts, whether in acidic or alkaline medium. Our in situ synchrotron radiation infrared spectra demonstrate that a P-H_ads intermediate is continually emerging on the Ru-NPC catalyst, actively proving the nonmetallic P catalytically active site in HER that is very different with previously reported metallic sites.