Excellent visible-light photocatalytic hydrogen production efficiency: hollow-structured TiO2/CdS/Au or hollow-structured TiO2/Au/CdS ternary heterojunction nanocomposites?

Abstract

Two ternary heterojunction composites, namely hollow-structured TiO2/CdS/Au and hollow-structured TiO2/Au/CdS, were successfully synthesized by preparing hollow-structured TiO2 first, followed by the deposition of Au and CdS (with different deposition sequences), respectively. In these two composites, hollow-structured TiO2 nanotubes provide 1D structure with large specific area, which facilitate the immobilization of CdS and Au nanoparticles and the transfer of electrons. CdS is visible-light responsive and Au nanoparticles can improve photocatalytic efficiency by the formation of schottky barrier and surface plasmon resonance effect (SPR). The structures and phases, morphologies, surface and optical properties of the two composites were systematically characterized. TiO2/CdS/Au ternary heterojunction composite has efficient light absorption ability and excellent performances in photocatalytic hydrogen generation (up to 3600 μmol h−1 g−1), which is more than 4 times higher than that of TiO2/Au/CdS (800 μmol h−1 g−1). Therefore, in this way, we present a promising strategy to construct hybrid photocatalysts for hydrogen production.