Effect of B2O3 on the Structure, Properties and Antibacterial Abilities of Sol-Gel-Derived TiO2/TeO2/B2O3 Powders

Albena Bachvarova-Nedelcheva; Reni Iordanova; Angelina Stoyanova; Nelly Georgieva; Veronica Nemska; Tsvetelina Foteva

doi:10.3390/ma16196400

Effect of B₂O₃ on the Structure, Properties and Antibacterial Abilities of Sol-Gel-Derived TiO₂/TeO₂/B₂O₃ Powders

Materials (Basel). 2023 Sep 25;16(19):6400. doi: 10.3390/ma16196400.

Authors

Albena Bachvarova-Nedelcheva¹, Reni Iordanova¹, Angelina Stoyanova², Nelly Georgieva³, Veronica Nemska³, Tsvetelina Foteva³

Affiliations

¹ Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bld. 11, 1113 Sofia, Bulgaria.
² Department Chemistry and Biochemistry, Faculty of Pharmacy, Medical University-Pleven, Kl. Ohridski Str., 1, 5800 Pleven, Bulgaria.
³ Department Biotechnology, Faculty of Chemical and Systems Engineering, University of Chemical Technology and Metallurgy, Kl. Ohridski Blvd, 8, 1756 Sofia, Bulgaria.

Abstract

This paper studies the influence of B₂O₃ on the structure, properties and antibacterial abilities of sol-gel-derived TiO₂/TeO₂/B₂O₃ 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 H₃BO₃ and H₆TeO₆ 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-TeO₂, anatase, rutile and TiTe₃O₈) 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 TiO₂ nanoparticles. The IR results showed that the short-range order of the amorphous phases that are part of the composite materials consists of TiO₆, BO₃, BO₄ and TeO₄ structural units. Free B₂O₃ was not detected in the investigated compositions which could be related to the better connectivity between the building units as compared to binary TiO₂/B₂O₃ 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.

Keywords: IR; UV-Vis spectra; antibacterial properties; photocatalysis; sol-gel.

Grants and funding

The authors acknowledge the project Д01-272-“European Network on Materials for Clean Technologies” for providing the opportunity to present the results at the SizeMat4 conference as well as for the financial publication support.