Phase-Controlled Synthesis of Ru Supported on Carbon Nitride and the Application in Photocatalytic H Evolution.

This work aims to explore the influence of crystal phase engineering on the photocatalytic hydrogen evolution activity of Ru/CN systems. By precisely tuning the combination of Ru precursors and reducing solvents, we successfully synthesized Ru co-catalysts with distinct crystal phases (hcp and fcc) and integrated them with CN. The photocatalytic hydrogen evolution experiments demonstrated that hcp-Ru/CN achieved a significantly higher hydrogen evolution rate (24.23 μmol h) compared to fcc-Ru/CN (7.44 μmol h), with activity reaching approximately 42% of Pt/CN under the same conditions. Photocurrent and electrochemical impedance spectroscopy analyses revealed that hcp-Ru/CN exhibited superior charge separation and transfer efficiency. Moreover, Gibbs free energy calculations indicated that the hydrogen adsorption energy of hcp-Ru (ΔG = -0.14 eV) was closer to optimal compared to fcc-Ru (-0.32 eV), enhancing the hydrogen generation process. These findings highlight that crystal-phase engineering plays a critical role in tuning the electronic structure and catalytic properties of Ru-based systems, offering insights for the design of highly efficient noble metal catalysts for photocatalysis.