Hgn@ZnS Yolk@Shell Nanocrystals for Solar Hydrogen Production

Abstract

Design of metal/semiconductor heterostructures has become a topic of great interest in recent years due to the combined interaction between the two components that allows them to show synergistic properties and functionalities. Yolk@shell nanocrystals composed of metal and semiconductor components represent a new family of heterostructures. These structures comprise a core, mobile particle surrounded by a hollow, permeable shell, which can be employed as a robust nanoreactor for catalytic applications. In comparison with the similar counterpart, core@shell nanocrystals, yolk@shell nanocrystal have superior features, such as homogeneous reaction environment, accelerated mass transfer dynamics and incremental surface active sites. In this work, a novel hollow Au nanospheres (HGN)@ZnS yolk@shell nanocrystal have been prepared and employed as photocatalysts for hydrogen production. The samples were synthesized by conducting ion exchange reactions on HGN@Cu2O core@shell nanocrystal template, which involved a Kirkendall anion exchange process and a kinetically controlled cation exchange reaction. The microstructures, electronic interactions, band alignment and interfacial charge dynamics of the resultant HGN@ZnS were characterized. The effects of HGN as a charge separation enhancer and a plasmonic sensitizer on the photocatalytic performance of hydrogen production were explored. The results revealed the great promise of HGN@ZnS as highly efficient photocatalysts for solar hydrogen production.