The swelling transition of lepidocrocite-type protonated layered titanates into anatase under hydrothermal treatment.
The common facets of anatase crystals are the (001) and (101) planes. However, the phase transformation from lepidocrocite-type titanate into anatase by hydrothermal processing yields an anatase microstructure with high concentration of exposed (010) planes. The phase transformation of a lepidocrocite-type protonated layered titanate (HTO) into anatase was studied using XRD, TEM, FTIR, and measurement of pH and zeta potential. It was found that HTO is proton-deficient. The phase transformation process begins after uptake of a sufficient number of protons into the lepidocrocite-type structure. With the uptake of protons new hydroxyl groups form on the internal surfaces of the layered titanate and result in a bilayer state of HTO. The phase transformation reaction is a topotactic dehydration reaction in which anatase forms and water is expelled by syneresis.
MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, the Netherlands.
Huiyu
H
Yuan
MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, the Netherlands.
Rogier
R
Besselink
MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, the Netherlands.
Zhaoliang
Z
Liao
MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, the Netherlands.
Johan E
JE
Ten Elshof