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. Poly(platinaynes) are used for the first time as an efficient donor for graphitic carbon nitride (g‐C3N4) to form a bulk heterojunction (BHJ) photocatalyst. This BHJ produces a sixfold higher hydrogen generation rate than that of pristine g‐C3N4. This indicates that poly(platinaynes) are a promising alternative to Pt metal cocatalysts for photocatalytic hydrogen generation at a much reduced Pt content.