Isolating Clusters of Light Elements in Molecular Sieves with Atom Probe Tomography.

ABSTRACT: Understanding the 3-D distribution and nature of active sites in heterogeneous catalysts is critical to developing structure-function relationships. However, this is difficult to achieve in microporous materials as there is little relative z-contrast between active and inactive framework elements (e.g., Al, O, P, and Si), making them difficult to differentiate with electron microscopies. We have applied atom probe tomography (APT), currently the only nanometer-scale 3-D microscopy to offer routine light element contrast, to the methanol-to-hydrocarbons (MTH) catalyst SAPO-34, with Si as the active site, which may be present in the framework as either isolated Si species or clusters (islands) of Si atoms. ²⁹Si solid-state NMR data on isotopically enriched and natural abundance ma

SUBMITTER: Schmidt JE 

PROVIDER: S-EPMC6065070 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature