From Average to Local Structure: A Rietveld and an Atomic Pair Distribution Function (PDF) Study of Selenium Clusters in Zeolite-NdY

摘要

Synthesis of metal/semiconductor nanoparticles with narrow size distributions is a significant challenge in nanoscience. One promising approach to achieve such narrow distributions is to employ a crystalline host framework, such as a zeolite, to constrain the size and the shape of the nanoparticles. Several examples of this method have been reported, and the advantages relative to other techniques used to fabricate semiconductor nanoclusters discussed. In guest-host methods, short-range ordering of the guest molecules and distortions of the zeolite framework in the vicinity of these molecules, which can be observed in the form of diffuse X-ray scattering, makes the structural analysis nontrivial. Here, we describe the structure and short-range ordering of Se clusters in a zeolite Nd-Y and show how a detailed structure can be obtained by combining Rietveld and pair distribution function analysis.