Solar‐Driven Hydrogen Generation Catalyzed by g‐C₃N₄ with Poly(platinaynes) as Efficient Electron Donor at Low Platinum Content

Abstract A metal‐complex‐modified graphitic carbon nitride (g‐C₃N₄) bulk heterostructure is presented here as a promising alternative to high‐cost noble metals as artificial photocatalysts. Theoretical and experimental studies of the spectral and physicochemical properties of three structurally similar molecules Fo–D, Pt–D, and Pt–P confirm that the Pt(II) acetylide group effectively expands the electron delocalization and adjusts the molecular orbital levels to form a relatively narrow bandgap. Using these molecules, the donor–acceptor assemblies Fo–D@CN, Pt–D@CN, and Pt–P@CN are formed with g‐C₃N₄. Among these assemblies, the Pt(II) acetylide‐based composite materials Pt–D@CN and Pt–P@CN with bulk heterojunction morphologies and extremely low Pt weight ratios of 0.19% and 0.24%, respectively, exhibit the fastest charge transfer and best light‐harvesting efficiencies. Among the tested assemblies, 10 mg Pt–P@CN without any Pt metal additives exhibits a significantly improved photocatalytic H₂ generation rate of 1.38 µmol h⁻¹ under simulated sunlight irradiation (AM1.5G, filter), which is sixfold higher than that of the pristine g‐C₃N₄.