Smart Assembly of Sulfide Heterojunction Photocatalysts with Well-Defined Interfaces for Direct Z-Scheme Water Splitting under Visible Light.

A Z-scheme photocatalytic water-splitting system is an effective approach to integrate the advantages both hydrogen- and oxygen-evolution photocatalysts. The interfacial properties of the heterojunctions have a great influence on the efficiency through the crystal orientation and the charge kinetics. In this study, a general chemical vapor deposition process and a gentle cation-exchange method were combined to assemble Z-scheme photocatalysts between CdS and MnS. As a result of the well-defined heterojunction interfaces and distinctive structural benefits, without cocatalysts, the 1 D CdS/MnS hybrid photocatalyst exhibited a significantly increased photocatalytic H2 evolution rate of 1595 μmol h-1  g-1 (apparent quantum efficiency of 22.6 % at λ=420 nm), which is over 10.5 times higher than that of CdS. Moreover, a better photocatalytic stability is demonstrated over particulate (42 h cycling measurement) and photoelectrochemical (3000 min continuous measurement) systems. Overall, this work provides a unique experimental insight into high-quality heterojunction interface design and new Z-scheme photocatalyst synthesis.