Visible-light-induced generation of H2 by nanocomposites of few-layer TiS2 and TaS2 with CdS nanoparticles.

Graphene analogues of TaS2 and TiS2 (3-4 layers), prepared by Li intercalation followed by exfoliation in water, were characterized. Nanocomposites of CdS with few-layer TiS2 and TaS2 were employed for the visible-light-induced H2 evolution reaction (HER). Benzyl alcohol was used as the sacrificial electron donor, which was oxidized to benzaldehyde during the reaction. Few-layer TiS2 is a semiconductor with a band gap of 0.7 eV, and its nanocomposite with CdS showed an activity of 1000 μmol h(-1)  g(-1). The nanocomposite of few-layer TaS2, in contrast, gave rise to higher activity of 2320 μmol h(-1)  g(-1), which was attributed to the metallic nature of few-layer TaS2. The amount of hydrogen evolved after 20 and 16 h for the CdS/TiS2 and CdS/TaS2 nanocomposites was 14,833 and 28,132 μmol, respectively, with turnover frequencies of 0.24 and 0.57 h(-1), respectively.