Journal Article

FZJ-2014-03896

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Periodic Cation Segregation in Cs$_{0.44}$[Nb$_{2.54}$W$_{2.46}$O$_{14}$] Quantified by High-Resolution Scanning Transmission Electron Microscopy

Heidelmann, M. (Corresponding Author)FZJ* ; Barthel, J.FZJ* ; Cox, G. ; Weirich, T.FZJ*

2014
Cambridge University Press New York, NY

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Please use a persistent id in citations: doi:10.1017/S1431927614001330

Abstract: The atomic structure of Cs0.44[Nb2.54W2.46O14] closely resembles the structure of the most active catalyst for the synthesis of acrylic acid, the M1 phase of . Consistently with observations made for the latter compound, the high-angle electron scattering signal recorded by scanning transmission electron microscopy shows a significant intensity variation, which repeats periodically with the projected crystallographic unit cell. The occupation factors for the individual mixed Nb/W atomic columns are extracted from the observed intensity variations. For this purpose, experimental images and simulated images are compared on an identical intensity scale, which enables a quantification of the cation distribution. According to our analysis specific sites possess low tungsten concentrations of 25%, whereas other sites have tungsten concentrations above 70%. These findings allow us to refine the existing structure model of the target compound, which has until now described a uniform distribution of the niobium and tungsten atoms in the unit cell, showing that the similarity between Cs0.44[Nb2.54W2.46O14] and the related catalytic compounds also extends to the level of the cation segregation.

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Contributing Institute(s):

1. Mikrostrukturforschung (PGI-5)

Research Program(s):

1. 424 - Exploratory materials and phenomena (POF2-424) (POF2-424)

Appears in the scientific report 2014

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Database coverage:
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