Characterization of CdS quantum dots encapsulated within zeolite Y

摘要

We prepared CdS quantum dots (QDs) within zeolite Y by exposing rigorously dried Cd~(2+)-exchanged zeolite Y to H_2S under the dry condition. Contrary to the previous reports [1, 2], our results unambiguously showed that the generated CdS QDs exist within the supercages of zeolite Y regardless of the loaded amount. We also found that while the moisture adsorption into the dry CdS-QD-incorporating zeolite Y leads to the formation of large pseudo spherical QDs with the diameter of 3-7 nm within the host by breaking the framework, coating of the surface of the dry CdS-QD-incorporating zeolite Y with octadecyltrimethoxysilane (ODM) leads to direct interconnection of the initially formed intrasupercage QDs into 'interconnected QDs' without breaking the framework. Interestingly, the degree of CdS QD interconnection increases with increasing the size of the zeolite for a given loaded amount of CdS.