Inhibition of Crystallite Growth in the Sol-Gel Synthesis of Nanocrystalline Metal Oxides
Nae-Lih Wu,
1*
Sze-Yen Wang,
1
I. A. Rusakova
2
Crystal growth upon firing of hydrous transition metal
oxide gels can be effectively inhibited by replacing the surface
hydroxyl group before firing with another functional group that does
not condense and that can produce small, secondary-phase particles that
restrict advancing of grain boundaries at elevated temperatures. Accordingly, fully crystallized SnO2, TiO2, and
ZrO2 materials with mean crystallite sizes of ~20, 50, and 15 angstroms, respectively, were synthesized by replacing the
hydroxyl group with methyl siloxyl before firing at 500°C. An
ultrasensitive SnO2-based chemical sensor resulting from
the microstructural miniaturization was demonstrated.
1 Department of Chemical Engineering, National
Taiwan University, Taipei, Taiwan 106, Republic of China.
2 Texas Center for Superconductivity at the
University of Houston, Houston, TX 77204-5932, USA.
*
To whom correspondence should be addressed. E-mail:
nlw001{at}coms.ntu.edu.tw
