TY - JOUR
T1 - Morphological and kinetic studies on hexagonal tungstates
AU - Michailovski, Alexej
AU - Kiebach, Wolff-Ragnar
AU - Bensch, Wolfgang
AU - Grunwaldt, Jan-Dierk
AU - Baiker, Alfons
AU - Komarneni, Sridhar
AU - Patzke, Greta R.
PY - 2007
Y1 - 2007
N2 - 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.
AB - 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.
U2 - 10.1021/cm061020o
DO - 10.1021/cm061020o
M3 - Journal article
SN - 0897-4756
VL - 19
SP - 185
EP - 197
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 2
ER -