Titania Samples Research Articles

Mesoporous titania as sorbent for 99Mo/99mTc generators column with low specific activity molybdenum-99 for nuclear medicine application

Abstract The 99Mo/99mTc generator is a chromatography column system that can be eluted to obtain technetium-99m (99mTc) for nuclear medicine applications in the hospital. Mesoporous titania is developed for the Mo adsorbent of a 99Mo/99mTc generator column employing low specific activity 99Mo produced by nuclear reactor irradiation of natural molybdenum. A symmetric triblock copolymer of P123 was used as a template to create mesoporous titania using the sol-gel process.. The molar ratio of the reactant (titanium tetraisopropoxide (TTIP) and titanium chloride (TiCl4)) was applied with ratios 1:1 and 3:2. Then, the different temperature calcination also was implied at 450 °C and 550 °C. The resulting mesoporous titania was studied utilizing thermal gravimetry analysis (TGA), nitrogen adsorption-desorption, and characterization analysis of X-ray diffraction. Furthermore, the Mo adsorption test was conducted by batch method. The highest molybdenum adsorption capacity of mesoporous titania samples is 34.62 mg Mo g−1 adsorbent. Mesoporous titania has the potential as a novel adsorbent for the 99Mo/99mTc generator column.

ULPING-Based Titanium Oxide as a New Cathode Material for Zn-Ion Batteries

The need for alternative energy storage options beyond lithium-ion batteries is critical due to their high costs, resource scarcity, and environmental concerns. Zinc-ion batteries offer a promising solution, given zinc’s abundance, cost effectiveness, and safety, particularly its compatibility with non-flammable aqueous electrolytes. In this study, the potential of laser-ablation-based titanium oxide as a novel cathode material for zinc-ion batteries was investigated. The ultra-short laser pulses for in situ nanostructure generation (ULPING) technique was employed to generate nanostructured titanium oxide. This laser ablation process produced highly porous nanostructures, enhancing the electrochemical performance of the electrodes. Zinc and titanium oxide samples were evaluated using two-electrode and three-electrode setups, with cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge (GCD) techniques. Optimal cathode materials were identified in the Ti-5W (laser ablated twice) and Ti-10W (laser ablated ten times) samples, which demonstrated excellent charge capacity and energy density. The Ti-10W sample exhibited superior long-term performance due to its highly porous nanostructures, improving ion diffusion and electron transport. The potential of laser-ablated titanium oxide as a high-performance cathode material for zinc-ion batteries was highlighted, emphasizing the importance of further research to optimize laser parameters and enhance the stability and scalability of these electrodes.

The Electrocatalytic Role of Oxygen Vacancy in Nitrate Reduction Reactions.

Ammonia, with high energy density and easy transportation, holds significant potential to become an integral part of future energy systems. Among tremendous strategies, electrocatalytic ammonia production is no doubt an efficient and eco-friendly method. One particularly intriguing class of electrocatalysts for reducing nitrate to ammonia is transition metal oxides, which have been heavily researched. However, how these catalysts' oxygen vacancy (VO) affects their performance remains elusive. To address this, taking titania (the most important catalyst) as an example, we carried out experimental investigations and simulations. Contrary to the prevailing belief that the concentrated VO would increase the catalytic efficiency of nitrate reduction, it was found that a relatively low level of VO is favorable for maximizing catalytic efficiency. At low cathodic voltages, titania with minimal VO delivered both the highest reduction efficiency and the best selectivity among the different titania samples in this paper. In addition to outlining the merits of lower electron transfer resistance and accelerated reaction dynamics, we also put forth a previously unmentioned factor, the adsorption of hydrogen or the creation of an ordered hydrogen bond network, which put up a hydrogen-rich atmosphere for following nitrate reduction. Further simulation study revealed that within the hydrogen-rich atmosphere isolated VO serves as the ideal active center to enable the lowest energy barriers for the reduction of nitrate into ammonia. These findings offer fresh insights into the working mechanism of oxide-based electrocatalysts for ammonia production.

Multi-Criteria Decision-Making Approach for Pre-Synthesis Selection of the Optimal Physicochemical Properties of TiO2 Photocatalytic Nanoparticles for Biomedical and Environmental Applications.

Nanomaterials are widely used in several biomedical and environmental applications, due to their ideal properties. However, the synthetic and characterization procedure requires significant costs and has a negative environmental impact. Various methods are available in order to control the pre-synthesis design of the produced materials, predicting their behavior and minimizing the series of experiments. Multi-Criteria Decision-Making is proposed in this study in order to determine the best combination of the physicochemical parameters and to define the best alternative among fifteen different samples of nanostructured titanium dioxide. In particular, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method was applied to achieve a final ranking of the available alternatives by avoiding several of the trials that would follow testing the biological effect and the photocatalytic degradation of organic pollutants. Thus, this approach helps us to stay environmentally and ethically correct, saving time, money, and energy and also providing an optimization of the nanomaterials that are developed.

Effects of TiO2 Nanoparticles Synthesized via Microwave Assistance on Adsorption and Photocatalytic Degradation of Ciprofloxacin.

In this study, the optimal microwave-assisted sol-gel synthesis parameters for achieving TiO2 nanoparticles with the highest specific surface area and photocatalytic activity were determined. Titanium isopropoxide was used as a precursor to prepare the sol (colloidal solution) of TiO2. Isopropanol was used as a solvent; acetylacetone was used as a complexation moderator; and nitric acid was used as a catalyst. Four samples of titanium dioxide were synthesized from the prepared colloidal solution in a microwave reactor at a temperature of 150 °C for 30 min and at a temperature of 200 °C for 10, 20, and 30 min. The phase composition of the TiO2 samples was determined by X-ray diffraction analysis (XRD) and Fourier-transform infrared spectroscopy (FTIR). Nitrogen adsorption/desorption isotherms were used to determine the specific surface area and pore size distributions using the Brunauer-Emmett-Teller (BET) method. The band-gap energy values of the TiO2 samples were determined by diffuse reflectance spectroscopy (DRS). The distribution of Ti and O in the TiO2 samples was determined by SEM-EDS analysis. The effects of adsorption and photocatalytic activity of the prepared TiO2 samples were evaluated by the degradation of ciprofloxacin (CIP) as an emerging organic pollutant (EOP) under UV-A light (365 nm). The results of the photocatalytic activity of the synthesized TiO2 nanoparticles were compared to the benchmark Degussa P25 TiO2. Kinetic parameters of adsorption and photocatalysis were determined and analyzed. It was found that crystalline TiO2 nanoparticles with the highest specific surface area, the lowest energy band gap, and the highest photocatalytic degradation were the samples synthesized at 200 °C for 10 min. The results indicate that CIP degradation by all TiO2 samples prepared at 200 °C show a synergistic effect of adsorption and photocatalytic degradation in the removal process.

Impact of Au on the transition temperature and photocatalytic activity of TiO2

The effect of gold (Au) addition on the anatase to rutile transition temperature (ART) of titanium dioxide (TiO2) was investigated. Concentrations of 2, 4, 8 and 16 mol. % of Au have been synthesised via a sol–gel technique and calcined at various temperatures (500–900 °C). The inclusion of gold improves the ART at 700 °C, maintaining 44.5 % anatase content for 4 % Au. Density functional theory studies indicated that the addition of Au in the anatase phase results in considerable lattice distortions, while Au 4d states and occupied Ti 3d orbitals contribute to the valence-conduction band energy gap upon doping. However, no sign of lattice substitution was observed in the experimental analysis. Instead, we demonstrate that the actual structure is well described by gold nanoparticles deposited on anatase and present a detailed DFT description of gold-modified anatase (101). All Au-TiO2samples exhibit reduced photocatalytic degradation properties compared to the control TiO2 at 500 °C. However, after calcining at 600 °C the addition of Au increases the photocatalytic activity of TiO2 from 49 % to 61 %, at an optimal concentration of 2 % Au-TiO2. The modification of titania with gold does push the transition temperature higher. However, this comes at the cost of reduced activity for 1,4-dioxane degradation, with the unmodified titania sample having better overall photocatalytic activity.

Influence of the TiO2 crystalline phase on the performance of UVA/brookite/persulfate and UVA/anatase/persulfate systems for the degradation of isothiazolinones in aqueous matrices

The activation of persulfate (PS) under UVA irradiation by two TiO2 polymorphs (brookite and anatase) and titanate photocatalysts was evaluated for the simultaneous removal of the biocides methylisothiazolinone (MIT) and chloromethylisothiazolinone (CMIT), in ultrapure water and real sewage treatment plant water (SW). Titania and titanate samples were synthesized by a hydrothermal method and characterized by XRD, SEM, N2 adsorption-desorption isotherms and UV-Vis DR. The reactions were performed in individual (brookite, anatase, titanate and PS) and hybrid (titania/PS and titanate/PS) systems and compared to those with TiO2-P25 as reference. In ultrapure water, the combined brookite/PS system showed a higher performance for MIT and CMIT abatement and a stronger synergistic effect between titania and PS than found in anatase/PS and titanate/PS systems, indicating the higher effectiveness of the brookite phase for PS activation under UVA. The use of SW water revealed the strong inhibitory effect of matrix constituents in the individual brookite, anatase and PS systems, which exhibited a low performance. However, the kinetics of MIT/CMIT in SW were greatly enhanced in the hybrid TiO2/PS systems, especially with brookite, leading to an efficient degradation of both pollutants and the decrease of total organic carbon (TOC). The addition of chemical scavengers showed a similar reactivity of HO• towards both isothiazolinones whereas a preferential attack of SO4•− to MIT was observed, demonstrating the selective nature of SO4•−.

Studying the ability of the food additive E171 (titanium dioxide) to induce gene mutations in bacteria

Introduction. Titanium dioxide in the Russian Federation is approved for use in the food industry, in the production of medicines and hygiene products. The food additive E171 is a mixture of micro- and nanoparticles of TiO2. In 2010, IARC classified TiO2 in nanoform as a probably carcinogenic to humans (Group 2B). In vitro and in vivo studies of the genotoxicity of titanium dioxide revealed contradictory results, indicating both the presence and absence of TiO2 mutagenicity. 
 The aim of the work is to evaluate the mutagenicity of the food additive E171 in the Ames test using standard and modified protocols.
 Materials and methods. The ability of food additive E171 (China) to induce reverse gene mutations in 5 strains of Salmonella typhimurium was studied under standard and modified conditions (cultivation of bacteria in the presence of methylated b-cyclodextrin (MCD) and/or pre-incubation for 1 hour in potassium phosphate buffer, pH 5.5 containing 10 mM NaCl and/or 3M MCD).
 Results. A sample of food additive E171 based on rutile titanium dioxide does not induce gene mutations in S. typhimurium in standard experiments. Modification of the Ames test protocol (decrease of the incubation mixture pH, addition of 10 mM NaCl) revealed statistically significant dose-dependent effects in TA100, TA98, and TA97 strains under metabolic incubation conditions. However, the fold increase of the number of revertants in the experimental plates compared to the negative control was < 2.
 Limitations. The research is limited to the mutagenicity assessment of food additive E171 (titanium dioxide) in the Ames test.
 Conclusion. The evaluation of the mutagenicity of titanium dioxide in other in vitro and in vivo tests taking into account the size and shape of the particles, is necessary to resolve the issue of its genetic safety as a food dye. A full range of studies will be performed on other samples of titanium dioxide presented in the market of the Russian Federation.

Hard x-ray photoelectron spectroscopy reference spectra of Ti and TiO2 with Cr Kα excitation

Hard x-ray photoelectron spectroscopy using monochromatic Cr Kα radiation (5414.8 eV) has been used to acquire XPS and Auger data on pure titanium and titanium dioxide samples. Survey data, extended range high-resolution scans of all observed photoelectron peaks, and high-resolution scans of Auger lines are presented herein.

EFFECT OF MODIFYING ADDITIVES ON THE PHASE TRANSITION OF ANATASE TO RUTILE

The results of studies on changes in the chemical composition and structure of doped titanium hydroxide during thermal treatment are analysed. It is shown that anatase is formed at first under heating in all cases, and with further increase in temperature or in the duration of thermal treatment it is transformed into rutile. The temperature of the start of anatase-rutile transition depends on the type of doping component. The transition proceeds not abruptly at a certain temperature but gradually over a wide temperature range, while both compounds can exist simultaneously. At a constant temperature, the proportion of rutile increases with an increase in the duration of thermal treatment. It is concluded on the basis of the conducted studies that the samples of titanium dioxide in the presence of doping components represent the broad classes of non-stoichiometric compounds with different crystal structures, and the transition of anatase to rutile is not a polymorphic transformation of the 1st kind but it is a consequence of various chemical processes involving the release of anionic and/or cationic impurities into the gas or solid phases.

Signal-Decay Based Approach for Visualization of Buried Defects in 3-D Printed Ceramic Components Imaged with Help of Optical Coherence Tomography.

We propose the use of Optical Coherence Tomography (OCT) as a tool for the quality control of 3-D-printed ceramics. Test samples with premeditated defects, namely single- and two-component samples of zirconia, titania, and titanium suboxides, were printed by stereolithography-based DLP (Digital Light Processing) processes. The OCT tomograms obtained on the green samples showed the capability of the method to visualize variations in the layered structure of the samples as well as the presence of cracks and inclusions at depths up to 130 µm, as validated by SEM images. The structural information was visible in cross-sectional images as well as in plan-view images. The optical signal measured from the printed zirconia oxide and titanium oxide samples showed strong attenuation with depth and could be fit with an exponential decay curve. The variations of the decay parameter correlated very well with the presence of defects and material variation. When used as an imaging quantity, the decay parameter projects the position of the defects into 2-D (X,Y) coordinates. This procedure can be used in real time, it reduces the data volume up to 1000 times, and allows for faster subsequent data analysis and transfer. Tomograms were also obtained on sintered samples. The results showed that the method can detect changes in the optical properties of the green ceramics caused by sintering. Specifically, the zirconium oxide samples became more transparent to the light used, whereas the titanium suboxide samples became entirely opaque. In addition, the optical response of the sintered zirconium oxide showed variations within the imaged volume, indicating material density variations. The results presented in this study show that OCT provides sufficient structural information on 3-D-printed ceramics and can be used as an in-line tool for quality control.

Development of nano titania/polyvinylidene fluoride composite from new titanium(IV) derivative and its investigation on antibacterial, BSA interaction and cytotoxicity

A new heteroleptic complex of titanium(IV) has been synthesised and characterized by physico-chemical techniques. Complex [(C36H30N4O4)Ti] 2a, was obtained by treating Ti(OPri)4 with a new modifier bidentate ligand 1a (C24H20N2O2) as well as with 8-hydroxy quinoline in 1:1:2 stoichiometry in anhydrous benzene. The 2a was employed as a precursor for the synthesis of active rutile phase nano titania by sol-gel method. Nano TiO2 was embedded with PVDF to obtain a set of three TiO2/PVDF samples of composite materials in diverse compositions (30 wt%, 40 wt% and 50 wt%). Ligand 1a, titanium(IV) derivative 2a, nano titania and trio samples of TiO2/PVDF composites were subjected for antibacterial studies against four infective microbial strains such as Bacillus cereus, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa by well diffusion technique. The 50 wt%-TiO2/PVDF composite material exhibited efficient antibacterial activity against all four pathogens. Protein binding interaction of Bovine Serum Albumin (BSA) with the third sample of composite material was performed and the cytotoxicity of the same composite was also tested against HeLa and HT- 29 tumor cell lines and was evaluated by MTT assay. The IC50 values of 50 wt%-TiO2/PVDF were observed as 35.72 µg/ml and 39.42 µg/ml on HeLa and HT-29 cell lines, respectively.

Green Thermo-Photo Catalytic Production of Syngas Using Pd/Nb-TiO2 Catalysts.

In this contribution, a series of Pd-promoted Nb-doped titania samples were essayed in the gas-phase thermo-photo production of syngas from methanol/water mixtures. The Pd loading was tested in the 0.1 to 2.5 wt % range, leading to the presence of metallic nanoparticles under reaction. Reaction rates exceeding 52 mmol H2 g-1 h-1 and quantum efficiencies above 33% were obtained. The optimum sample having a 0.5 wt % of Pd provided an outstanding synergy between light and heat under reaction conditions, facilitating the boost of activity with respect to the single-source processes and achieving high selectivity to syngas. The spectroscopic analysis of the physico-chemical ground of the activity unveiled that the noble metal interaction with the Nb-doped anatase support triggers a cooperative effect, promoting the evolution of formic acid-type methanol-derived carbon-containing species and rendering a significant enhancement of syngas production. The proposed thermo-photo system is thus a firm candidate to contribute to the new green circular economy.

Hydrogen evolution on the reduced TiO2 under simulated solar lamp

Reduction of TiO2 have been performed under different conditions. Firstly, raw titania was soaked in the ammonia solution at pH= 10, and then was followed the hydrothermal treatment in autoclave at 150 °C for 1 h. Such obtained sample was then calcined in Ar at 500–700 °C. In the second attitude, hydrothermally prepared TiO2 at 150 °C was heat-treated at 500–700 °C under flowing of either hydrogen nor ammonia gas. The surface defects in the reduced TiO2 were analyzed by EPR. All the titania samples prepared at low heating temperature such as 500 °C showed surface defects in the form of hole traps and oxygen vacancies. With increase temperature of heat-treatment some electron traps and oxygen vacancies increased. Sample with the highest amount of the reduced Ti3+ centers was obtained at 600 °C under H2 treatment. This sample showed the highest yield in H2 production during water splitting under simulated solar light and the highest generation of photocurrent at λ = 388 nm. Formation of Ti3+ conducts to the narrowing of the titania band gap and can increase harvesting of the solar light. The presence of both, reduced anatase and rutile in TiO2 prepared at 600 °C under H2 could increase photoelectrons conductivity due to the photoelectron transfer between anatase and rutile particles. Moreover, the presence of Ti3+ could increase adsorption of water on TiO2 surface and improve the photocatalytic yield of water splitting. Hydrogen appeared to be a stronger reducing agent than ammonia gas.

A novel route to estimate the photocatalytic activity of titanium dioxide via voltage measurements

Titanium dioxide is known as a photocatalyst, that may be activated by UV-A light and thus be able to lead to chemical reactions, to mineralize organic compounds, to inactivate biomolecules and to kill microorganisms, respectively. To estimate the capability of the photocatalytic activity a novel experimental setup using photovoltage measurements was studied. A distinct correlation between the photocatalytic activity of the titanium dioxide samples and the measurable photovoltages could be demonstrated. The experimental setups included the construction of different electrochemical cells based on TiO2 and using different liquid and gel electrolytes. The investigations were carried out on titanium dioxide layers as well as on TiO2 particle materials. The electrochemical measurement of the resulting voltage was optimised and the results were compared with conventionally used methods for the determination of the photocatalytic activity like the decolourization of methylene blue solutions. Additionally, the increase of carbon dioxide concentration in the gas phase was taken as a measure for total mineralization. Results indicate strong correlations between the different methods.Graphical

Novel photoanodes based on (Mo-Cr) co-doped titania nanotube for highly efficient photocathodic protection performance of stainless steel

Mo-doped, Cr-doped, and Mo-Cr co-doped titania nanotube arrays were synthesized through the single step anodization of titanium. Mo-Cr co-doped titania nanotubes prepared showed great improvement on photocatalytic activity in the protection of stainless steel (403SS) under visible light irradiation compared with Mo and Cr mono-doped titania. The open-circuit potential (OCP) of 403SS (in 3.5 wt% aqueous NaCl) coupled with the best co-doped sample (Cr50:Mo50-TNT) was reduced from −240 to −690 mV, while the electrode potential was maintained at −320 mV even upon turning the light off. This study also identified the effect of the addition of sulfur compounds as hole scavengers on the photoelectrochemical (PEC) properties and photoelectrochemical cathodic protection (PCP) by the best Mo-Cr co-doped titania nanotube. Sodium sulfate and sulfite, sodium thiosulfate, sodium sulfide, potassium metabisulfite and thiourea have been used as hole scavengers. The order of photocurrent is as follows: Na2S > K2S2O5 > CS(NH2)2 > Na2S2O3 > no hole scavengers > Na2SO4 > Na2SO3. Mo-Cr co-doped titania nanotube show much more favorable PCP impact on 403SS than the pure titania sample, according to the results of the changes in the potentials and current densities. Furthermore, the results finally proved that sodium sulfide is the most appropriate hole scavenger.

Evaluation of Antifungal Properties of Titania P25.

Commercial titania photocatalyst—P25 was chosen for an antifungal property examination due to it exhibiting one of the highest photocatalytic activities among titania photocatalysts. Titania P25 was homogenized first (HomoP25) and then annealed at different temperatures. Additionally, HomoP25 was modified with 0.5 wt% or 2.0 wt% of platinum by a photodeposition method. The obtained samples were characterized by diffuse-reflectance spectroscopy (DRS), X-ray photoabsorption spectroscopy (XPS), X-ray diffraction (XRD) and Raman spectroscopy. Moreover, photocatalytic activity was tested for methanol dehydrogenation under UV/vis irradiation. The spore-destroying effect of photocatalysts was investigated against two mold fungal species, i.e., Aspergillus fumigatus and Aspergillus niger. Both the mycelium growth and API ZYM (estimation of enzymatic activity) tests were applied for the assessment of antifungal effect. It was found that annealing caused a change of surface properties of the titania samples, i.e., an increase in the noncrystalline part, a growth of particles and enhanced oxygen adsorption on its surface, which resulted in an increase in both the hydrogen evolution rate and the antifungal effect. Titania samples annealed at 300−500 °C were highly active during 60-min UV/vis irradiation, inhibiting the germination of both fungal spores, whereas titania modification with platinum (0.5 and 2.0 wt%) had negligible effect, despite being highly active for hydrogen evolution. The control experiments revealed the lack of titania activity in the dark, as well as high resistance of fungi for applied UV/vis irradiation in the absence of photocatalysts. Moreover, the complete inhibition of 19 hydrolases, secreted by both tested fungi, was noted under UV/vis irradiation on the annealed P25 sample. It is proposed that titania photocatalysts of large particle sizes (>150 nm) and enriched surface with oxygen might efficiently destroy fungal structures under mild irradiation conditions and, thus, be highly promising as covering materials for daily products.

Is Black Titania a Promising Photocatalyst?

Five different (commercial and self-synthesized) titania samples were mixed with NaBH4 and then heated to obtain black titania samples. The change in synthesis conditions resulted in the preparation of nine different photocatalysts, most of which were black in color. The photocatalysts were characterized by various methods, including X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), photoacoustic and reverse-double beam photoacoustic spectroscopy (PAS/RDB-PAS). The photocatalytic activity was tested for oxidative decomposition of acetic acid, methanol dehydrogenation, phenol degradation and bacteria inactivation (Escherichia coli) under different conditions, i.e., irradiation with UV, vis, and NIR, and in the dark. It was found that the properties of the obtained samples depended on the features of the original titania materials. A shift in XRD peaks was observed only in the case of the commercial titania samples, indicating self-doping, whereas faceted anatase samples (self-synthesized) showed high resistance towards bulk modification. Independent of the type and degree of modification, all modified samples exhibited much worse activity under UV irradiation than original titania photocatalysts both under aerobic and anaerobic conditions. It is proposed that the strong reduction conditions during the samples’ preparation resulted in the partial destruction of the titania surface, as evidenced by both microscopic observation and crystallographic data (an increase in amorphous content), and thus the formation of deep electron traps (bulk defects as oxygen vacancies) increasing the charge carriers’ recombination. Under vis irradiation, a slight increase in photocatalytic performance (phenol degradation) was obtained for only four samples, while two samples also exhibited slight activity under NIR. In the case of bacteria inactivation, some modified samples exhibited higher activity under both vis and NIR than respective pristine titania, which could be useful for disinfection, cancer treatment and other purposes. However, considering the overall performance of the black titania samples in this study, it is difficult to recommend them for broad environmental applications.

Performance of commercial titanium dioxide samples in terms of dye photodegradation assessed using smartphone-based measurements

The photocatalytic activity of four titanium dioxide samples (TiO2-P25 Degussa, PC105 Millennium, PC500 Millennium, and Anatase) was studied in the degradation of dyes (Congo Red (CR), Methyl Orange (MO), and Direct Red 23 (DR23)) using cost-effective smartphone-based analysis. The obtained kinetic curves are well described by the first-order kinetic model. It was established that the phase composition, the size of the particles, and the specific surface area of ​​the catalyst have a significant effect on the photocatalytic activity of the studied TiO2 samples. It was investigated that the Millennium PC500 sample is the most effective photocatalyst due to a large specific surface area and a small particle size (8 nm). TiO2-P25 Degussa and Anatase also demonstrate a high photocatalytic activity in the degradation of CR and DR23 dyes, which can be explained by the accelerated process of electron transfer between the anatase and rutile phases. For the PC105 sample, a higher CR photodegradation efficiency is observed compared to PC500. It can be concluded that heterogeneous photocatalysis is an effective method for the removal of toxic dyes from wastewater. With the use of smartphone-based analysis, it is possible monitoring the photodegradation kinetics in real-time.

Shockwave impact on the stability of anatase titania nanoparticles

The stability of anatase titania nanoparticles was investigated under exposure to repeated loading of shockwaves produced in a diaphragm-driven high-pressure shock tube. The titania samples were exposed to 20 shocks with pressure, temperature, and steady exposure time in the range of 20.5 – 26 bar, 1399 – 2101 K, and 1.74 – 1.83 ms, respectively. The crystal structure and surface morphology were analyzed before and after the shockwave treatment using various characterization techniques. After repeated shock exposure, there was reduction in crystallite size by ~ 40%, modification in the surface charge, and an increase in the hydroxyl groups in titania. The onset of phase transformation from anatase to rutile was observed after 20 shocks. This work gives insights into the structural changes induced by shockwaves in anatase nanoparticles which can help improve their performance as a catalytic support in heterogeneous catalysis.