Anatase Form Research Articles

Preparation of Y–TiO2@MIL-53(Fe) and performance study of photocatalytic degradation of tetracycline

Y–TiO2@MIL-53(Fe) photocatalyst composites were synthesized by a facile solvothermal method and their photocatalytic activity were assessed by photodegradation of tetracycline (TC) under visible light irradiation. Comprehensive material characterization, including XRD, XPS, BET, UV–Vis, SEM, and PL techniques, were employed to analyze the properties of the composites. Experimental results revealed that the removal rates of TC from a 20 mg/L TC solution using Y–TiO2, MIL-53(Fe), and Y–TiO2@MIL-53(Fe) were 61.0%, 75.1%, and 93.2% respectively, under specific conditions of 500 W UV-Hg lamp irradiation, a 30 min dark reaction, a 60 min light reaction, a Ti:Fe molar ratio of 1:1, and a catalyst concentration of 0.6 g/L. The Y–TiO2 component in Y–TiO2@MIL-53(Fe) primarily existed in the form of anatase, while Fe3+ ions entered the lattice gap or replaced Ti4+ ions at certain lattice positions, effectively inhibiting the recombination of photoelectrons and holes and broadening the light absorption band. This modification positively influenced the photocatalytic ability of the composites. Quenching experiments and ESR characterization confirmed that •O2−, •OH, and h+ were the active species involved in the photocatalytic process, with •O2− being the main active species. This investigation of the photocatalytic properties of the composites provides valuable insights into the photocatalytic reaction mechanism, supporting the application and further development of photocatalytic technology.

In Ukrainian

The influence of the electronic subsystem of nanographene particles modified with titanium dioxide nanoparticles on the thermal destruction of the polymer matrix is analyzed. The variation in the conductivity of the modifiers made it possible to vary the effect of the metallic electronic system of graphene on thermal destruction by attenuating its effect through the transfer of energy to the electronic subsystem throughout the semiconductor film of anatase and excluding its effect on thermal destruction through a wide-band TiO2 dielectric of rutile form, which is opaque for energy transfer to the electronic subsystem. The application of such films does not affect the thermal processes in which the phonon subsystems of polymer, graphene and crystal modifiers are involved. The method of thermally programmable desorption mass spectrometry investigated the thermal destruction of hybrid composites of epoxy resin with graphene, namely the effect of surface modification of multilayer graphene particles by nanoparticles of pyrogenic titanium dioxide (anatase and rutile forms) on the thermal stability of hybrid epoxy composites in the temperature range of 40 − 800 °C. The activation energies Ed of destruction of atomic fragments of the polymer structure with the value m/z in the range of 16 ‒ 140 D were determined. It has been established that the thermal destruction of fragments of the polymer structure of epoxy resin composites with graphene modified with anatase and rutile forms of titanium dioxide is determined by the peculiarities of thermal transport at the polymer-modifier interfaces. Modification of graphene particles by the anatase form of titanium dioxide leads to increased thermal stability of polymer chains and cross-links in epoxycomposites in the entire range of m/z values of desorbed fragments. Filling the resin with graphene particles coated with the rutile form of TiO2 practically does not affect the intensity of thermal destruction of the composite matrix. The Ed values of different destruction fragments in composites with unmodified and modified graphene are in the range of 50 ‒ 130 kJ/mol. The value of Ed increases by 5 ‒ 10 kJ/mol when the resin is filled with graphene nanoparticles, while the coating of particles with titanium dioxide of the anatase and rutile phases practically does not change the value of Ed of the vast majority of fragments.

Structure, wettability and photocatalytic activity of graphene doped multi-walled carbon nanotubes/titanium dioxide hybrid coatings

This paper presents the findings of the structure, wettability and photocatalytic activity of 32 wt % graphene-doped multi-walled carbon nanotubes (G-MWCNTs) / titanium dioxide (TiO2) hybrid coatings under three different ratios. The hybrid coatings of G-MWCNTs/TiO2 were compared with the pure (undoped) TiO2 coating. Pure TiO2 and G-MWCNTs/TiO2 hybrid coatings were prepared by sol-gel method and deposited on soda-lime-silica (SLS) glass substrates using a dip coater. The samples were heat-treated in the air at 500 °C for 1 h. The nano-sized G and MWCNTs used as dopants in the resulting hybrid solution were mixed without agglomeration by the sonication method based on the DLVO theory, without any surfactants. To prevent the migration of Na+ ions contained in the structure of SLS glass to TiO2-based coatings, a SiO2-based sol-gel coating was first deposited on the SLS glass surface using the dip coating method. This was done before applying the pure TiO2 coating and G-MWCNTs/TiO2 hybrid coating process. All samples were crystallized in the anatase form and exhibited superhydrophilic behavior. The G-MWCNTs/TiO2 hybrid coated samples' photoactivity was determined using the ISO 10678 MB degradation standard. According to the ISO 10678:2010 MB degradation standard, G-MWCNTs/TiO2 hybrid coated samples exhibited photonic efficiency.

Epoxide-Mediated Synthesis of Two-Component Al2O3–TiO2 Aerogels and Their UV-Protective Characteristics

A new method was proposed to synthesize aerogels based on Al2O3–TiO2 by the hydrolysis of mixed solutions of titanium tetrachloride and aluminum nitrate in the presence of propylene oxide, followed by supercritical drying of the obtained gels. The aerogels are characterized by a high specific surface area (140–500 m2/g) and a high specific porosity (1.7–2.7 cm3/g). Heat treatment of the Al2O3–TiO2 aerogels at temperatures up to 600°C does not lead to crystallization of titanium dioxide, whereas the formation of crystalline anatase in aerogels based on individual TiO2 is observed already at a temperature of 450°C. Using the standardized ISO 24443-2016 method, the SPF value of the obtained materials was determined, which turned out to be comparable to the characteristics of a commercial inorganic UV filter based on TiO2 (Kronos 1171). At the same time, the photocatalytic activity of the Al2O3–TiO2 aerogels turned out to be more than 120 times lower than the similar characteristics of the commercial UV filter based on titanium dioxide. The results obtained demonstrated that the Al2O3–TiO2 aerogels are promising as components of sunscreens.

Modeling of sputter-based atomic layer deposition with altered parameters

Computational modeling of the sputtering process forming atomic layers of some technologically significant materials was performed based on sputter rate relation. Bismuth atomic layer deposition at different polar angles and ion fluence were shown. The atomic layers getting deposited were studied as a function of incident Argon ion energy at different pressure and a curve analogous to the Bragg curve was obtained. The sputtering parameters were varied to get different atomic layers of TiOx films and the variation of coverage with sticking coefficient was shown. The rate of change of partial sputtering yield with coverage was depicted in the sputter-based deposition of TiN films. The deposition pressure and time were varied to get films of different thicknesses. All the simulated results were correlated with experimental findings with features like variation of reactive gas pressure, electron aided momentum transfer in Bi, multilayer anatase and rutile formation in TiO2 and effect of process parameters on TiN.

Development of porous ceramic coatings via the PEO process: The key role of CuO nanoparticles in methylene blue photodegradation under visible light illumination

The TiO2/CuO coatings were applied on pure titanium via PEO, observing the photocatalytic capacity for methylene blue (MB) degradation. Additionally, the effect of the ionization process at room temperature on the photocatalytic efficiency of the coatings was studied. A coating containing CuO nanoparticles (NPs) presented a more porous morphology. Phase analysis results proved that coatings containing CuO NPs were comprised of anatase and CuO phases, while the addition of ionized-CuO NPs into the electrolyte led to the formation of anatase, rutile, CuO, and TiP2O7. The CuO-incorporated coating exhibited 76 % efficient MB photodegradation. Most importantly, the introduction of 1 g/L CuO-ionized NPs at 25 °C increased photocatalytic efficiency to 90 % after 6 h of visible light illumination. Moreover, the optimum coating satisfied photocatalytic efficiency even after 3 runs. A deep investigation into the effect of photocatalytic parameters, including concentrations (2.5, 5, 10 and 15 ppm) and pH of pollutants (3 and 9), was also performed. Furthermore, appropriate scavengers such as isopropanol (0.1 mM), ascorbic acid (0.1 mM), and potassium bromate (0.1 mM) were employed to scrutinize the role of various photogenerated reactive species and to detail the photocatalytic mechanism.

Green synthesis of blue titania nanoparticles by pulsed laser ablation in water

This work aimed at using pulsed laser ablation in water (PLAW) for the production of titanium dioxide nanoparticles in water from a commercially pure titanium target. There is great commercial interest in nanotitania, which can be found in products including paints, coatings, textiles, cosmetics, solar panels, and catalysts. Nevertheless, nanotitania is usually obtained through chemical routes, which are cost-intensive and cause a negative environmental impact. PLAW comes as a cleaner option for obtaining nano-TiO2 since it uses only solid titanium and deionized water as raw materials. After the process, an optical micrography of the Ti targets was carried out to assess the interaction of the laser with the metallic surface. The nanoparticles were characterized by DLS, TEM, Raman, XRD, and UV–Vis. Nano-TiO2 activity as a photocatalyst was tested for the degradation of the dye RR141. TEM images point to two populations of produced nanoparticles: one spherical with average sizes between 8 and 13 nm, and one spindle-like with the major axis average ranging between 17 and 35 nm. Composition analyses with XRD and Raman indicate the formation of anatase, rutile, and amorphous titania. The color of the solution produced was bluish, which may indicate the presence of surface defects that extend the light absorption band to the visible range. The catalysis experiments showed suitable results for the UV spectrum, and the calculated bandgaps were close to that of anatase, around 3.2 eV.

Highly efficient oxidative C–H/C–H cross coupling of xanthines over bimetallic Ni/Ag@titania: The key role of surface polymorphism and mechanism by surface-enhanced Raman scattering

A new effiecient protocol for the cross dehydrogenative coupling (CDC) of C8(sp2)-H/C(sp2)-H of xanthines and aromatic compounds over nanosized bimetallic Ni/Ag@titania catalyst is presented. The notable properties of Ni/Ag bimetallic nanoparticles (NPs) facilitate the 2-fold activation of classically inert C(sp2)-H bonds. Molecular level study for the catalyst efficiency was determined, by performing the model reaction between caffeine and vanillin, on different catalysts, synthesised by varying the loading of two component metals, on four polymorphic forms of titania, brookite, rutile, anatase and mesoporous. Among the 63 catalyst systems, 5:1 Ni/Ag@anatase showed excellent catalytic activity in dry DMSO with 88% product formation. Tert-butyl hydroperoxide (TBHP) and H2O2 were used as oxidant. The regioselectivity of the CDC reaction depends on the nature of peroxide used. Non-covalent surface π-stacking interaction occurring between peroxide modified titania (PMT) and aromatic ring(s) is the key for the observed regioselectivity. Catalysts were characterised by UV–Vis, FT-IR, powder XRD, XPS, SEM, TEM, etc. The catalytic system showed good operational stability, functional group tolerance, robustness and recyclability. We identified the intermediate(s) through real time monitoring of SERS and proposed the most plausible catalytic cycle as well. Further, a possible energy profile diagram involving the transition states was obtained computationally by DFTB calculations. Almost all the products were afforded in good to excellent yields. Thus, the present process constitutes one straightforward and clean approach to a class of much sought organic transformation.

Selective Photocatalytic Reduction of 3‐Nitrophenol to 3‐Aminophenol by Anatase and Rutile TiO2 – What Stands Behind the Photoactivity?

AbstractThe photocatalytic selective reduction of 3‐nitrophenol to 3‐aminophenol was studied in the presence of titanium dioxide in the form of various anatase and rutile compositions. The reaction progress is altered by various parameters, which can be classified as intrinsic (depending on the chemical, structural, and electronic features) and extrinsic (depending on the reaction and conditions). The goal of the studies was to understand the influence of intrinsic factors and to compare the performance of anatase and rutile materials. The (photo)electrochemical analysis revealed unequivocally the differences in interfacial electron transfer, charge recombination, reduction driving force, and methanol photooxidation efficiency for titania polymorphs. It appeared that all mentioned processes were phase‐dependent, and they contributed unequally to overall photocatalytic activity. In particular, methanol oxidation was the most efficient at the rutile phase, which overcame the critical limitation of the oxidation pathway and facilitated the reduction of 3‐nitrophenol. On the other hand, the dark electron transfer efficiency was highest at the anatase phase, despite the lower driving force in this case. The presented thorough and systematic analysis of the discussed photocatalytic system (the photocatalyst and the reaction) should allow the rational design of efficient and selective photocatalysts.

Synergy of Cu2+-Cu(OH)2-CuO with TiO2 coatings, fabricated via plasma electrolytic Oxidation: Insights into the multifaceted mechanism governing visible light-driven photodegradation of tetracycline

In this study, copper oxide-embedded TiO2 coatings were introduced on pure titanium via plasma electrolytic oxidation (PEO), which exhibited photocatalytic capacity for tetracycline (TC) degradation. Moreover, the impact of the ionization process and its temperature on the photocatalytic efficiency were investigated. All coatings containing CuO nanoparticles (NPs) exhibited finer micropores, higher specific areas, and higher wettability. The phase analysis results prove that coatings containing CuO NPs are composed of anatase and CuO phases, whereas the addition of ionized CuO NPs into the electrolyte leads to the formation of anatase, rutile, CuO, TiP2O7, and Cu(OH)2. All the CuO-incorporated coatings resulted in highly efficient TC photodegradation, the highest of which was 70 % for the coating containing 1 g/L CuO NPs. Most importantly, the introduction of1 g/L CuO-ionized NPs at 25 °C increased the photocatalytic efficiency to 92 %, whereas increasing the ionization process to 60 °C significantly decreased the photocatalytic activity to 60 % after 6 h of visible light illumination. Moreover, the optimum coating satisfied the photocatalytic efficiency requirement even after five cycles. An in-depth investigation of the effect of photocatalytic parameters, including the concentration and pH of pollutants, as well as the light intensity, was also performed. Appropriate scavenger tests were employed to examine the impact of different reactive oxygen species and photocatalytic mechanisms. Finally, based on the intermediate products, a probable TC photodegradation pathway was suggested.

Magnetic heterostructures of NiFe2O4 and TiO2: Pechini synthesis, characterization and photocatalytic performance in arsenite oxidation

In this work, the aim was to synthesize photocatalysts containing NiFe2O4 and TiO2, forming heterostructures applied in the decontamination of As (III) in an aqueous medium. The photocatalysts were prepared using the polymeric precursor method and calcined at three temperatures (500, 700 and 900 °C). The synthesized samples presented different crystalline phases: NiFe2O4, α-Fe2O3, NiO, and the allotropic forms of TiO2 anatase and rutile. The band gap values for all the samples were lower than those reported in the literature for TiO2. The sample calcined at 700 °C showed the best performance in the photocatalytic removal of As (III), resulting in the removal of 97.5 % of its concentration after 80 min. Additionally, it was possible to achieve a magnetic recovery of the catalyst after each cycle, with a recovery rate exceeding 80 %. This can be associated with a higher nickel ferrite content in relation to α-Fe2O3 and NiO simple oxides, the presence of both TiO2 polymorphs (anatase and rutile) in considerable amounts, and a lower band gap energy value.

Extensive function of green synthesized titania nanoparticles: Photodegradation of Congo red

Several extensive research studies have explored the advantages of green templates in the synthesis of structure and morphology-controlled photocatalytic nanomaterials. This paper compares the abilities of zingiber rhizome extract (ZE) and tapioca starch extracts (TS) in modifying the surface and optical properties of titania nanoparticles (TNP) synthesized by solgel technique. The synthesized nanocatalysts were characterized using various physicochemical techniques. While zingiber (ginger) extract effectively promotes the formation of dual anatase and rutile phases, tapioca extract supports formation of the single anatase phase of titania. These two extracts were examined for the degradation of Congo red in the presence of sunlight. The photomineralization and recyclability of catalysts were evaluated through total organic content analysis. The easy recovery and reusability of zingiber and tapioca biomasses, along with good control over the growth of nanoparticles, enable them to be implicit novel green templates in the successful synthesis of photoactive mesoporous nanotitania.

Environmental aspects of using artificial photosynthesis technology for environmental decarbonization

The increasing levels of carbon dioxide (CO2) in the atmosphere have been recognized as a major contributor to global climate change. As a result, there is a pressing need to develop sustainable and eco-friendly methods for mitigating CO2 emissions. CO2 recycling has emerged as a promising solution, aiming to convert CO2 into valuable products while reducing its impact on the environment. This work uses the CO2 recycling approach, which involves the conversion of CO2 emissions into useful organic compounds. An experiment with artificial photosynthesis is carried out with the help of a special installation, where CO2 undergoes photochemical reactions that contribute to the formation of organic compounds. Photocatalytic conversion of CO2 is environmentally friendly as it uses light energy and renewable raw materials to produce valuable chemicals without producing harmful by-products or waste. It has been established that TiO2 in the form of anatase and rutile is the most common CO2 photocatalyst. As a result of the experiment, the main output products were methanol, acetate aldehyde and acetone. The use of ultraviolet radiation and an electric field significantly affected the synthesis of organic substances and their quantity. It can be used in various industries such as fuel, chemical and pharmaceutical industries. In particular, methanol, acetate aldehyde and acetone are promising substances for the use and production of biofuels.

Development of TiO2-Based nanocomposite film for colorimetric detection of glucose

This study proposes the development of a colorimetric non-enzymatic glucose sensor based on TiO2/I2/CMC (TIC) nanocomposite film. A solution-cast approach was employed for the synthesis of nanocomposite film. The structural and morphological study of the nanocomposite film was analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transforms infrared (FTIR), Raman spectroscopy, photoluminescence, and dynamic light scattering. The XRD graph and Raman spectra indicate the synthesized nanocrystalline anatase form of TiO2 nanoparticles. The characteristic peak of Ti-O-Ti bonds is observed between 600 and 850 cm−1 in the FTIR spectrum. Additionally, TIC film exhibited antibacterial properties against E. coli and Bacillus subtilis. The colorimetric method was utilized to determine the glucose concentration. The TIC film reveals that the minimum detectable concentration is 0.4 mM. This easy-to-develop TIC nanocomposite film shows good stability. Therefore, it can be a promising candidate for glucose-sensing applications.

Cr(VI) reduction by nitrogen annealed free-standing anodic TiO2 nanotubes formed in ethylene glycol-Na2CO3 electrolyte

Free-standing anodic TiO2 films consisting of vertically oriented nanotubes (NTs) were produced by the anodization of titanium (Ti) in ethylene glycol (EG) added with 1 M Na2CO3. The volume of Na2CO3 gives effect on the adhesion of TiO2 oxide with Ti substrate. The film is easily removed from the Ti foil for the addition of ≤ 2 vol% 1 M Na2CO3 only, which resulted in free-standing TiO2 NTs (FSTNTs). The FSTNTs then were annealed in different atmospheres, either in air or nitrogen (N2) to induce the TiO2 anatase phase. Better crystallinity of anatase is achieved for the N2-annealed sample compared to the air-annealed sample. The annealing temperature also gives effect on the anatase formation. A photoreduction experiment was performed on all samples, and the results showed that the FSTNTs annealed in N2 at 600 ℃ exhibited an excellent photocatalytic activity under simulated solar light. The conversion of Cr(VI) to Cr(III) reached ∼89% within 2 h. N2 insertion within the oxide was possible, which narrowed the energy band gap, allowing photocatalytic properties under the visible light region.

Anatase-cellulose acetate for reinforced desalination membrane with antibacterial properties

This study aimed to prepare antifouling and highly mechanical strengthening membranes for brackish and underground water desalination. It was designed from cellulose acetate (CA) loaded anatase. Anatase was prepared from tetra-iso-propylorthotitanate and carboxymethyl cellulose. Different concentrations of anatase (0.2, 0.3, 0.5, 0.6, 0.7, and 0.8)% were loaded onto CA during the inversion phase preparation of the membranes. The prepared membranes were characterized using Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM & EDX), mechanical properties, swelling ratio, porosity determination, and ion release. The analysis confirmed the formation of anatase on the surface and inside the macro-voids of the membrane. Furthermore, anatase loading improved the CA membrane’s mechanical properties and decreased its swelling and porosity rate. Also, CA-loaded anatase membranes displayed a significant antibacterial potential against Gram-positive and Gram-negative bacteria. The results showed that the salt rejection of the CA/anatase films as-prepared varies considerably with the addition of nanomaterial, rising from 46%:92% with the prepared membranes under the 10-bar operation condition and 5 g/L NaCl input concentration. It can be concluded that the prepared CA-loaded anatase membranes have high mechanical properties that are safe, economical, available, and can stop membrane biofouling.

Carbon-modified TiO2 as a promising and efficient admixture for cementitious composites: A comprehensive study of photocatalytic, mechanical and structural properties

Carbon-modified titanium(IV) oxide with improved photocatalytic properties under visible light was used as an admixture for cement composites. For this purpose, two commercially available titanium(IV) oxides differing in crystallographic form, and two synthesized for the experiment from titanyl sulfate hydrate and titanium(IV) isopropoxide were used as starting materials, with ethylene glycol as the carbon source. The effect of carbon modification on the surface of titania was to increase the BET surface area, which resulted in a greater tendency of TiO2 nanoparticles to aggregate and agglomerate, higher water adsorption on the oxide surface, and lower temperature stability. Nevertheless, electrokinetic studies demonstrated the stability of modified titanium(IV) oxides in alkaline media, and the increased BET surface area led to a significant increase in their activity in a photodegradation reaction, especially in the visible light range in the case of oxides containing a higher content of the anatase form. The photocatalytic properties of titanium(IV) oxides were maintained after incorporation into the cement matrix. For composites with carbon-modified titania admixtures an improvement in photocatalytic activity was higher in the UV than in the visible light range. In general, modification of titanium(IV) oxide with carbon did not significantly affect the mechanical and durability properties of the cement composites. For both modified and unmodified oxides, a reduction in heat during hydration of the cementitious binder and increases in flexural and compressive strengths were observed at later curing times. This is related to the presence of TiO2 nanoparticles, which, being additional active centers, contribute to the initiation of C–S–H phase growth and refinement of the composite structure, as confirmed by the increased proportion of micro- and nanopores. An additional effect of introducing titanium(IV) oxide, especially the anatase variety, into the cement matrix was an improvement in the antibacterial properties of the composite.

Photocatalytic Performance of Sol-Gel Prepared TiO2 Thin Films Annealed at Various Temperatures.

Titanium dioxide (TiO2) in the form of thin films has attracted enormous attention for photocatalysis. It combines the fundamental properties of TiO2 as a large bandgap semiconductor with the advantage of thin films, making it competitive with TiO2 powders for recycling and maintenance in photocatalytic applications. There are many aspects affecting the photocatalytic performance of thin film structures, such as the nanocrystalline size, surface morphology, and phase composition. However, the quantification of each influencing aspect needs to be better studied and correlated. Here, we prepared a series of TiO2 thin films using a sol-gel process and spin-coated on p-type, (100)-oriented silicon substrates with a native oxide layer. The as-deposited TiO2 thin films were then annealed at different temperatures from 400 °C to 800 °C for 3 h in an ambient atmosphere. This sample synthesis provided systemic parameter variation regarding the aspects mentioned above. To characterize thin films, several techniques were used. Spectroscopic ellipsometry (SE) was employed for the investigation of the film thickness and the optical properties. The results revealed that an increasing annealing temperature reduced the film thickness with an increase in the refractive index. Atomic force microscopy (AFM) was utilized to examine the surface morphology, revealing an increased surface roughness and grain sizes. X-ray diffractometry (XRD) and UV-Raman spectroscopy were used to study the phase composition and crystallite size. The annealing process initially led to the formation of pure anatase, followed by a transformation from anatase to rutile as the annealing temperature increased. An overall enhancement in crystallinity was also observed. The photocatalytic properties of the thin films were tested using the photocatalytic decomposition of acetone gas in a home-built solid (photocatalyst)-gas (reactant) reactor. The composition of the gas mixture in the reaction chamber was monitored using in situ Fourier transform infrared spectroscopy. Finally, all of the structural and spectroscopic characteristics of the TiO2 thin films were quantified and correlated with their photocatalytic properties using a correlation matrix. This provided a good overview of which film properties affect the photocatalytic efficiency the most.

The Role of Cerium Valence in the Conversion Temperature of H2Ti3O7 Nanoribbons to TiO2-B and Anatase Nanoribbons, and Further to Rutile.

CeO2-TiO2 is an important mixed oxide due to its catalytic properties, particularly in heterogeneous photocatalysis. This study presents a straightforward method to obtain 1D TiO2 nanostructures decorated with CeO2 nanoparticles at the surface. As the precursor, we used H2Ti3O7 nanoribbons prepared from sodium titanate nanoribbons by ion exchange. Two cerium sources with an oxidation state of +3 and +4 were used to obtain mixed oxides. HAADF-STEM mapping of the Ce4+-modified nanoribbons revealed a thin continuous layer at the surface of the H2Ti3O7 nanoribbons, while Ce3+ cerium ions intercalated partially between the titanate layers. The phase composition and morphology changes were monitored during calcination between 620 °C and 960 °C. Thermal treatment led to the formation of CeO2 nanoparticles on the surface of the TiO2 nanoribbons, whose size increased with the calcination temperature. The use of Ce4+ raised the temperature required for converting H2Ti3O7 to TiO2-B by approximately 200 °C, and the temperature for the formation of anatase. For the Ce3+ batch, the presence of cerium inhibited the conversion to rutile. Analysis of cerium oxidation states revealed the existence of both +4 and +3 in all calcined samples, regardless of the initial cerium oxidation state.

Synthesis and characterization of TiO2 nanoparticles combined with geraniol and their synergistic antibacterial activity

BackgroundThe emergence of antibiotic resistance in pathogenic bacteria has become a global threat, encouraging the adoption of efficient and effective alternatives to conventional antibiotics and promoting their use as replacements. Titanium dioxide nanoparticles (TiO2 NPs) have been reported to exhibit antibacterial properties. In this study, we synthesized and characterized TiO2 NPs in anatase and rutile forms with surface modification by geraniol (GER).ResultsThe crystallinity and morphology of modified TiO2 NPs were analyzed by UV/Vis spectrophotometry, X-ray powder diffraction (XRD), and scanning electron microscopy (SEM) with elemental mapping (EDS). The antimicrobial activity of TiO2 NPs with geraniol was assessed against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia coli. The minimum inhibitory concentration (MIC) values of modified NPs ranged from 0.25 to 1.0 mg/ml against all bacterial strains, and the live dead assay and fractional inhibitory concentration (FIC) supported the antibacterial properties of TiO2 NPs with GER. Moreover, TiO2 NPs with GER also showed a significant decrease in the biofilm thickness of MRSA.ConclusionsOur results suggest that TiO2 NPs with GER offer a promising alternative to antibiotics, particularly for controlling antibiotic-resistant strains. The surface modification of TiO2 NPs by geraniol resulted in enhanced antibacterial properties against multiple bacterial strains, including antibiotic-resistant MRSA. The potential applications of modified TiO2 NPs in the biomedical and environmental fields warrant further investigation.