Effect of B(2)O(3) on the Structure, Properties and Antibacterial Abilities of Sol-Gel-Derived TiO(2)/TeO(2)/B(2)O(3) Powders

This paper studies the influence of B(2)O(3) on the structure, properties and antibacterial abilities of sol-gel-derived TiO(2)/TeO(2)/B(2)O(3) powders. Titanium(IV) butoxide, telluric(VI) acid and boric acid were used as precursors. Differences were observed in the degree of decomposition of Ti butoxide in the presence of H(3)BO(3) and H(6)TeO(6) acids. The phase transformations of the obtained gels in the temperature range of 200–700 °C were investigated by XRD. Composite materials containing an amorphous phase and different crystalline phases (metallic Te, α-TeO(2), anatase, rutile and TiTe(3)O(8)) were prepared. Heating at 400 °C indicated a crystalline-to-amorphous-phase ratio of approximately 3:1. The scanning electron microscopy (SEM) analysis showed the preparation of plate-like TiO(2) nanoparticles. The IR results showed that the short-range order of the amorphous phases that are part of the composite materials consists of TiO(6), BO(3), BO(4) and TeO(4) structural units. Free B(2)O(3) was not detected in the investigated compositions which could be related to the better connectivity between the building units as compared to binary TiO(2)/B(2)O(3) compositions. The UV-Vis spectra of the investigated gels exhibited a red shift of the cut-off due to the presence of boron and tellurium units. The binary sample achieved the maximum photodegradation efficiency (94%) toward Malachite green dye under UV irradiation, whereas the ternary sample photoactivity was very low. The compositions exhibited promising antibacterial activity against E. coli NBIMCC K12 407.