Solar‐Driven Hydrogen Generation Catalyzed by g‐C ₃ N ₄ with Poly(platinaynes) as Efficient Electron Donor at Low Platinum Content

A metal‐complex‐modified graphitic carbon nitride (g‐C 3 N 4 ) 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‐C 3 N 4 . 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 H 2 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‐C 3 N 4 .