Scalable fabrication of ZnxCd1-xS double-shell hollow nanospheres for highly efficient hydrogen production

Hollow nanostructures are of great scientific and technological importance for extensive applications in photocatalysis, drug delivery, wastewater treatment, etc. In this study, we have developed a facile hydrothermal method for the large scale fabrication of alloyed ZnxCd1-xS double-shell (DS-ZnxCd1-xS) hollow nanospheres using hierarchically porous ZnS nanospheres as sacrificial templates and the reagent Cd(Ac)2 as a Cd source. The growth mechanism of double-shell hollow nanospheres has been studied and illustrated by investigating the morphological evolution of the inter-mediated products. Moreover, the chemical composition and void space between the double-shells of the as-obtained alloyed ZnxCd1-xS hollow nanospheres can be regulated by adding a certain amount of Cd(Ac)2. The optical properties and band structures have been investigated using UV–vis diffuse reflectance spectroscopy (DRS), Mott-Schottky analysis and valence-band (VB) X-ray photoelectron spectroscopy, respectively. When evaluated for their photocatalytic properties, the as-prepared alloyed Zn0.46Cd0.54S double-shell (DS-Zn0.46Cd0.54S) hollow nanospheres exhibit excellent hydrogen production, and a H2 evolution speed of up to 4.11 mol h−1 g−1 is reached under irradiation of visible light (λ > 420 nm).