A nanohybrid of CdTe@CdS nanocrystals and titania nanosheets with p-n nanojunctions for improved visible light-driven hydrogen production

A nanohybrid photocatalyst composed of CdTe@CdS nanocrystals and single-layered exfoliated titania nanosheets was synthesized through a well-defined restacking approach. The nanohybrid possessed an expanded layered structure, with ultrathin titania nanosheets randomly restacked upon each other and CdTe@CdS nanocrystals sandwiched between the nanosheets. The introduction of CdTe@CdS nanocrystals not only extended the light absorption of the photocatalyst to the visible range, but also formed p–n nanojunctions in the nanohybrid. The resultant materials containing same amount of CdTe@CdS nanocrystals exhibited over 43 times higher activity than pure CdTe@CdS nanocrystals for hydrogen production under visible light irradiation (λ > 420 nm) while titania nanosheets alone were not capable of producing any hydrogen under the same conditions. The superior photocatalytic efficiency of the nanohybrid can be attributed to the effective charge separation, which is achieved by the synergetic effect of proper energy bands alignment and p–n nanojunctions