The E-DAX spectrum of pure TiO2 nano particles is given in
Fig. 4(a). The spectrum has prominent peaks of titanium (Ti) and
oxygen (O). From the peaks, it is confirmed that the nano particles
synthesized by sol–gel technique using optimal growth parameters
belong to pure TiO2. The weight contributions of titanium and
oxygen are 61.45% and 33.83%, respectively and they contribute
96.56% of the total weight. It confirms the purity of TiO2 nano particles
synthesized by sol–gel technique is good. The E-DAX spectrum
of dyed TiO2 nano particles is shown in Fig. 4(b). The dyed TiO2
shows another prominent peak of dye’s functional group (COOH)
in addition to the prominent peaks of Ti and O. The weight contributions
of titanium, oxygen and dye’s functional group are 30.51%,
30.50% and 29.84%, respectively and they contribute 90.85% of the total weight. The chemical composition of pure TiO2 and dyed TiO2
nano particles estimated by E-DAX spectrum is given in Table 1.