Characteristic of TiO2&Ag0 nanocomposites formed via transformation of metatitanic acid and titanium (IV) isopropoxide

Abstract

Composite nanoparticles TiO2&Ag0 were synthesized by coprecipitationin a weakly alkaline medium in the presence of various precursors - metatitanic acid and titanium (IV) isopropoxide. Comparative study of TiO2&Ag0 included analysis of morphology (SEM), phase (XRD) and chemical compositions (EDS). The formation of anatase structures was confirmed at a relatively low concentration of silver (0–8 wt% for metatitanic acid and 0–4 wt% for Ti (IV) isopropoxide). An increase in the Ag fraction to 8 wt% led to the appearance of the Ti2O3 and β-TiO2 phases in the Ti(IV) isopropoxide system. The size distribution of primary particles is 8.3–10.6 nm (Ti(IV) isopropoxide system) and 12.3–14.0 nm (metatitanic acid system). The anatase lattice parameters decrease with Ag wt% increasing in Ti(IV) isopropoxide system and do not change for the metatitanic acid system. TG-DTA study showed the effects corresponding to the removal of structural water (210 °C), destruction of isopropoxide and combustion of organic matter (300–410 °C), crystallization of anatase (510 °C) and the anatase transformation into the rutile phase (720–760 °C), but in the presence silver, the anatase structure did not change to 1000 °C. Morphological study shows high crystallinity of both kinds of structures but less aggregative stability composites formed in the metatitanic acid solution. All type nanocomposites include four chemical elements – Ti, Ag, O, and Na as well as a small number of various admixtures - S or Cl and K depending on precursor species. At the same time, a relatively high concentration of argentum in the initial solution led to obtaining chemically pure composite nanoparticlesandcore&shell type structures.