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

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.