Highly Promoted Photocatalytic Hydrogen Generation by Multiple Electron Transfer Pathways

Abstract A facile development of highly efficient photocatalytic nanostructures for solar fuel production via controlled cocatalyst deposition is described. 2 nm-Pt nanoparticles were selectively synthesized by radiolysis on polypyrrole (PPy), TiO2 or on both PPy-TiO2 (noted respectively (Pt-PPy)-TiO2, (Pt-TiO2)-PPy and Pt-(PPy-TiO2)). The PPy nanostructures not only act a photosensitizer, but also as a connection bridge between two light-harvesting semiconductors to form a p-n heterojunction, which absorbs UV and visible light efficiently. The designed heterojunction photocatalyst nanostructures (Pt-(PPy-TiO2)) exhibit broadened absorption to the visible region, long life-time of charge carriers and high photocatalytic activity for hydrogen production. This activity is markedly enhanced compared with that of (Pt-PPy)-TiO2 and (Pt-TiO2)-PPy, and is ascribed to more efficient multiple electron transfer pathways. Such designed structures provide promising ways for selected site deposition of metal nanoparticles on heterojunction semiconductors in high efficiency conversion from solar energy to solar fuel application.