Synergistic Effect of TP-Ru Complex with Optimized Ru-NP-Loaded Exfoliated g-C₃N₄ for Photocatalytic Green Hydrogen Production

Engineering semiconductors with sensitizers and metals is a recognized strategy for enhancing solar-driven photocatalytic hydrogen production. This study delves into the synergistic impact of utilizing exfoliated g-C₃N₄ (EC₃N₄) loaded with ruthenium metal (Ru) and sensitized with a triphenylphosphine ruthenium (TP-Ru) complex to elevate solar-driven H₂ evolution. By altering the morphology of g-C₃N₄ to exfoliate nanosheets, a 1.30-fold increase in H₂ production was achieved, attributed to defect formation, facilitating higher charge separation efficiency. Bimetallic Ru and TP-Ru-based cocatalysts exhibit distinct photocatalytic efficiencies, functioning as polymer sensitizers and charge-trapping agents, respectively. Sensitizing EC₃N₄ with the TP-Ru complex resulted in enhanced visible light absorbance, leading to a significantly higher H₂ production. Notably, the performance of Ru was 1.88-fold higher than that of the TP-Ru complex, owing to the efficient separation of charge carriers by Ru. The highest H₂ production of 2562.5 μmol g^-1 h^-1 was achieved when the bimetallic Ru/TP-Ru was attached to EC₃N₄, surpassing production with 3% Ru/EC₃N₄, 3% TP-Ru/EC₃N₄, EC₃N₄, and g-C₃N₄ samples by factors of 1.62, 3.04, 38.68, and 48.81, respectively. The optimized Ru/TP-Ru/EC₃N₄ composite also reveals a quantum yield of 3.745% with continuous hydrogen production in multiple cycles. Ru effectively traps electrons, while the TP-Ru complex maximizes the light absorbance efficiency of g-C₃N₄ in addition to charge separation. This synergistic interplay of the TP-Ru complex with Ru enhances the hydrogen production efficiency of the EC₃N₄ nanotexture under solar energy. This innovative approach presents a promising pathway for constructing highly efficient composites for visible light-driven H₂ evolution and holds potential for various solar energy applications.