Reatividade das nanopartículas de dióxido de titânio com a superfície modificada por grupos peróxo
Abstract
The welfare of the human population depends of the
technological and scientific development. However, this model of economic
growth has generated a huge ecological impact. For this reason, it is necessary
new and more efficient processes and methods of synthesis to sage energy. This
study employed a new approach of the "The Oxidant PeroxoMethod" (OPM) to
obtain highly reactive nanoparticles of titanium dioxide (TiO2) with the surface
modified with peroxide groups (TiO2 -OPM). We synthesized these TiO2-OPM
using titanium metal and titanium isopropoxide as titanium source and to
evaluate the reactivity of these precursors, two different composition of bismuth
titanates (the selenita Bi12TiO20 and the perovskite Bi4Ti3O12 phases) were
synthesized by means of the conventional solid-state reaction. These materials
were characterized using differential scanning calorimetry (DSC),
thermogravimetric analysis (TG), X-ray diffraction (XRD), Raman spectroscopy
and scanning eléctron (SEM) and transmission eléctron (TEM) microscopies.
We observed that both TiO2-OPM precursors are identical reagarding their
reactivity and structure, with the advantage that the material synthesized from
the alcooxide is easier, cheaper and faster that the material obtained from
titanium metal. Moreover, we could observe that the peroxide groups on the
surface of the nanoparticles were resposable by the reactivity of these
nanoparticles, as observed by the lower temperatures used to obtain single phase
bismuth titanates with different composition.