Highly efficient H₂ evolution over ZnO-ZnS-CdS heterostructures from an aqueous solution containing SO₃^2- and S^2- ions

ZnO-ZnS-CdS heterostructure photocatalysts for water splitting were designed and prepared by a wet chemistry method. It was found that ZnO-ZnS-CdS heterostructures are highly active photocatalysts for H₂ evolution under simulated solar light irradiation in an aqueous solution containing SO₃^2- and S^2- ions as sacrificial reagents. H₂ evolution with (ZnO)₂-(ZnS)₁-(CdS)₁ heterostructure reaches up to 2790 μmol h⁻¹ g⁻¹. The photoexcited electrons in the ZnO-ZnS-CdS heterostructures have a much longer lifetime (>225 ns) than that of the sole ZnO, ZnS, and CdS (<65 ns). The favorable interface processes of the heterostructures make a significant contribution to high photocatalytic H₂ evolution rate.