Hydrothermal synthesis of multifunctional TiO2-ZnO oxide systems with desired antibacterial and photocatalytic properties

The aim of the study was the synthesis of multifunctional TiO2-ZnO oxide systems with desired antibacterial and photocatalytic activity. It was investigated how the TiO2:ZnO molar ratio and the time of hydrothermal treatment affected the physicochemical and structural properties (including morphology, crystalline and porous structure, as well as chemical surface composition) of the synthesized materials. For the first time this type of binary oxide systems were used as antibacterial materials against Gram-positive, Gram-negative and anaerobic bacteria. Moreover, the photocatalytic properties of the obtained materials were verified in the degradation of C.I. Basic Violet 10 dye. The SEM analysis demonstrates that binary oxide materials based on TiO2 and ZnO were found to have spherically and hexagonally shaped particles, characteristic of both oxides. The results of XRD, Raman and HRTEM analysis proved that the molar ratio of the components affects the crystalline structure of the synthesized oxide materials. Analysis of porous structure parameters showed that an increase in the ZnO content leads to a decrease in the BET surface area. Moreover, low-temperature N-2 sorption analysis demonstrates that TiO2-ZnO oxide systems have higher surface are than the pure oxides. The TiO2-ZnO oxide systems exhibited very good antibacterial activity against Gram-positive bacteria, especially Staphylococcus aureus (including methicillin-resistant Staphylococcus aureus). The photo-oxidation tests proved that the binary oxide materials (especially the T9Zn1 samples) demonstrates high photocatalytic activity in the decomposition of C.I. Basic Violet 10 (95% after 180 min irradiation) compared with the reference titania sample.