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All Roads Lead to TiO2: TiO2-Rich Surfaces of Barium and Strontium Titanate Prepared by Hydrothermal Synthesis

Authors :
Michael J. Bedzyk
Laurence D. Marks
Robert M. Kennedy
Jianguo Wen
Lawrence A. Crosby
Bor-Rong Chen
Kenneth R. Poeppelmeier
Source :
Chemistry of Materials. 30:841-846
Publication Year :
2018
Publisher :
American Chemical Society (ACS), 2018.

Abstract

Through high-resolution electron microscopy, the surface structure of barium titanate and strontium titanate nanoparticles are found to be terminated by a TiO2 double layer. These results confirm prior observations of TiO2-rich surface reconstructions on strontium titanate nanoparticles made hydrothermally at high pH and single crystals prepared with wet chemical etching. Of all the reconstructions observed on single crystals for these two materials, we report for first time the √13 × √13R33.7° structure on the {001} facets of hydrothermally prepared barium titanate and strontium titanate nanocrystals. The aqueous environment common to the two preparation methods preferentially leaves strontium and barium depleted from the A-sites near the surface and leads to TiO2-terminated surfaces for both materials. Analysis indicates that the observed structures are the thermodynamic lowest energy structures in aqueous conditions.

Details

ISSN :
15205002 and 08974756
Volume :
30
Database :
OpenAIRE
Journal :
Chemistry of Materials
Accession number :
edsair.doi...........aa2a66ad2fa8bc5071f906bc28498e7f
Full Text :
https://doi.org/10.1021/acs.chemmater.7b04404