Influence of precursor type on structural, morphological, dielectric and magnetic properties of TiO₂ nanoparticles

Influência do tipo precursor nas propriedades estruturais, morfológicas, dielétricas e magnéticas das nanopartículas de TiO₂

Abstract

TiO₂ nanoparticles (NPs) were synthesized by sol-gel methods using two different precursors, titanium tetraisopropoxide and potassium titanium oxalate (KTO). The precursors had a profound influence on the structural, morphological, dielectric and magnetic properties of synthesized TiO₂ NPs, as evidenced by the XRD, FE-SEM, TEM, LCR and VSM studies in the synthesized samples. Alkoxide-derived TiO₂ NPs contained mostly mixed phases of anatase and rutile, whereas KTO-derived TiO₂ NPs contained anatase and Magnéli phases (Ti_nO_2n-1). After heat treatment at 550 °C, the crystallite size of KTO-derived NPs was lower than alkoxide-derived TiO₂ NPs. The synthesized nanoparticles were spherical and agglomerated having anatase and rutile phases with different proportions in the microstructure of the alkoxide sample. Dielectric constant of the KTO-derived NPs was higher than the alkoxide-derived NPs. Diamagnetic behavior of KTO-derived NPs was also higher than the alkoxide-derived TiO₂ NPs.

Keywords:
TiO₂ nanoparticles; sol-gel; dielectric constant; grain size; anatase