Au@TiO2-CdS ternary nanostructures for efficient visible-light-driven hydrogen generation.

We report a new type of Au@TiO2-CdS ternary nanostructure by decorating CdS nanoparticles onto Au@TiO2 core-shell structures. In comparison to that of binary structures such as CdS-TiO2 and Au@TiO2, these ternary nanostructures exhibit a remarkably high photocatalytic H2-generation rate under visible-light irradiation. The enhanced photocatalytic activity is attributed to the unique ternary design, which builds up a transfer path for the photoexcited electrons of CdS to the core Au particles via the TiO2 nanocrystal bridge and thus effectively suppresses the electron-hole recombination on the CdS photocatalyst. This internal electron-transfer pathway (CdS → TiO2 → Au) eliminates the need for the postdeposition of the metal cocatalyst because the core Au nanoparticles can act as the interior active catalyst for proton reduction toward hydrogen evolution. We believe that our work demonstrates a promising way for the rational design of metal-semiconductor hybrid photocatalysts that can achieve a high photocatalytic efficiency for use in solar fuels production.