Bimetallic RuPc-La modified n-C₃N₄ nanosheets with the synergistic effect of oxidative/reductive active sites for stimulating photocatalytic green H₂ production

Hydrogen is a potential energy vector that substitutes for carbon fuels and can be effectively produced through photocatalytic water splitting. One of the most important technological advancements to raise the efficiency of H₂ production using solar energy is the synthesis of Pt-free co-catalysts. In this study, bimetallic ruthenium triphenylphosphine complex (RuPc) and lanthanum (La) were used with nanotextured graphitic carbon nitride to construct RuPc-La/n-C₃N₄ composite to produce hydrogen through photocatalytic water splitting. The synergistic effects of RuPc/La with n-C₃N₄ were systematically investigated in an internally illuminated photoreactor to maximize the hydrogen yield. The highest rate at which hydrogen evolves was 2833 μmol g⁻¹ h⁻¹ over 3RuPc-1La/n-C₃N₄ with methanol sacrificial reagent, which is 21.22 and 26.89 times higher than it was produced over n-C₃N₄ and g-C₃N₄, respectively. La was beneficial in providing oxidative reactive sites with enhanced lifetime of charges, whereas, the ruthenium complex promotes reductive reactions and increases light utilization. Thus, the synergistic interaction of RuPc/La enhances hydrogen evolution, which can be attributed to the providing oxidative/reductive active sites, speeding up charge transfer efficiency by inhabiting their recombination rate and enabling higher visible light utilization. The interaction of the RuPc/La metals ratio with the sacrificial reagents was further investigated and a significantly higher H₂ yield was observed with optimized parameters. This work offers a viable strategy for developing bimetallic metals-based cocatalysts that can aid in the photocatalytic hydrogen evolution process by combining with the nanostructured g-C₃N₄ nanosheets.