Sol-Gel Synthesis of SrTiO3 Nanoparticles Using
Acetic Acid as a Chelating Agent
Patama Visuttipitukul1 and Niti Yongvanich2,*
1
Department of Metallurgical Engineering, Faculty of Engineering, Chulalongkorn
University, Bangkok 10320, Thailand
2
Materials Science and Engineering, Faculty of Engineering and Industrial
Technology, Silpakorn University, Nakornpathom 73000, Thailand
SrTiO3 nanoparticles were synthesized by sol-gel method using acetic acid as a
chelating agent. The molar ratios between Ti and acetic acid for the chelated system
were 4:1 and 4:8. Thermal degradation of the gels was characterized by
thermogravimetric analysis (TGA). Complete decomposition of organic and
inorganic residues occurred at 650°C. For the chelated system, chelation or
complexation of the titanium cation is believed to occur. The –OH ligand should be
gradually replaced by the acetyl group, slowing down the reactivity between the Ti
and Sr cations. Fourier Transformed Infrared Spectroscopy (FTIR) revealed various
peaks whose position and appearance changed with calcination temperature. The SrO and Ti-O peaks were focused as the main indications of structural alterations
during phase transformation. X-rays diffraction (XRD) demonstrated only SrC2O4
(JCPDS#22-1437) with a small trace of anatase TiO2 (JCPDS#78-2486) between
400°C and 500°C. Dominant perovskite peaks were observed starting at 600°C and
could be indexed as cubic SrTiO3 (JCPDS#35-0734). Using the Scherrer’s formula,
the calculated sizes (19 – 42 nm) were systematically smaller at higher amount of
acetic acid when compared at the same calcination temperature. Such size reduction
could be explained by retardation in the hydrolysis reaction, resulting in a smaller
amount of the Ti-O-containing species readily available for formation of SrTiO3.
These unbalanced amounts of both Sr- and Ti-containing species were evidenced by
the presence of Sr3Ti2O7 impurity. The obtained nanoparticles were mostly isotropic
in shape with agglomeration due to partial sintering during calcination. Sinterability
was slightly improved in the chelated system, possibly due to the higher surface area
or the aid of liquid phase induced by the remaining unreacted Ti-species.
*Presenting author’s email: niti.yongvanich@gmail.com