Morphological and kinetic studies on hexagonal tungstates

Alexej Michailovski, Wolff-Ragnar Kiebach, Wolfgang Bensch, Jan-Dierk Grunwaldt, Alfons Baiker, Sridhar Komarneni, Greta R. Patzke

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Formation of nanostructured hexagonal alkali tungstates (HTBs) from ammonium metatungstate (AMT) and alkali chlorides has been investigated by a combined strategy encompassing in situ spectroscopic techniques and hydrothermal synthetic studies. They demonstrate how the morphology of the HTBs can be tuned by the straightforward hydrothermal reaction of ammonium metatungstate with the choice of appropriate alkali chlorides. The resulting particle shapes vary from highly anisotropic fibers to multilevel assemblies of hierarchically grown nanorods. Microwave-hydrothermal techniques have further expanded this morphological spectrum. Next, the growth process of alkali HTBs was explored for selected cases by combination of in situ EXAFS and EDXRD investigations. They both show that nucleation starts after a certain induction time and is strongly dependent on the concentration. Though the individual kinetics of alkali HTB formation differ slightly from each other, all alkali cations have a nucleation-controlled growth mechanism in common. © 2007 American Chemical Society.
Original languageEnglish
JournalChemistry of Materials
Volume19
Issue number2
Pages (from-to)185-197
ISSN0897-4756
DOIs
Publication statusPublished - 2007
Externally publishedYes

Cite this

Michailovski, A., Kiebach, W-R., Bensch, W., Grunwaldt, J-D., Baiker, A., Komarneni, S., & Patzke, G. R. (2007). Morphological and kinetic studies on hexagonal tungstates. Chemistry of Materials, 19(2), 185-197. https://doi.org/10.1021/cm061020o