Structure Of TiO2 Research Articles

Influence of copper and iron transition metals in the photocatalytic activity of titanium dioxide microspheres

This work proposes the combined sol–gel/solvothermal synthesis method to prepare Cu-doped TiO2 and Fe-doped TiO2 microstructures, and further study their photocatalytic activity in the degradation of Eriochrome Black T (EBT) at neutral conditions using a simulated sunlight source. TiO2:at%M (at%=0.25, 0.5, and 1.0; M = Cu or Fe) catalysts were characterized by X-ray diffractometry, Scanning electron microscopy, Diffuse reflectance UV–Vis spectroscopy, Raman spectroscopy, and Brunauer-Emmett-Teller surface area analysis. All synthesized catalysts showed TiO2 anatase phase with spherical morphology and average particle size of 4 to 8 μm. Transition metal doping did not modify the TiO2 anatase phase. TiO2:at%M catalysts exhibited lower bandgap energies than pure TiO2. TiO2:0.5at%Fe showed the lowest bandgap energy (2.87 eV). TiO2 catalysts with a transition metal content of 0.25at% showed a higher surface area compared to the rest of dopant concentrations. The inclusion of the metallic elements in the TiO2 structure enhances the photocatalytic efficiency of the TiO2 anatase under visible light. TiO2:0.25at%Cu showed the highest EBT degradation yields of 90% color removal, 61% total organic carbon (TOC) reduction, and 87% chemical oxygen demand decrease at 180 min. TiO2:0.25at%Cu and TiO2:0.50at%Fe microspheres retained good degradation efficiency for color and TOC removals even after being reused for three cycles.

Facile synthesis and enhanced acetone sensing properties of ZnO/TiO2 nanocomposite at room temperature

This paper reports a clear outline of the synthesis and gas-sensing characteristics of pure ZnO, TiO2 nanoparticles (NPs) and ZnO/TiO2 (ZT) nanocomposite (NC) for acetone detection at room temperature for diabetes screening. Thesamples were synthesized using an uncomplicated low-cost co-precipitation method. The ZT nanocomposites have shown a combined phase structure of ZnO (wurtzite) and TiO2 (anatase) from X-ray diffraction. The absorbance of the samples was analyzed by UV–Vis Spectrophotometer and a variation in the optical bandgap is studied.A high-performance ZT NC gas sensor is successfully realized for excellent selectivity, and quick response-recovery towards acetone detection. The sensing mechanism is ascribed to the composition, morphology, and enhanced oxygen adsorptionsites revealing better performances than the pure ZnO and TiO2 NPs. The ZT NC of composition ZnO (0.60 at.%):TiO2 (0.40 at.%) is observed to enhance the acetonegas detection signal for the lowest sub micro level ppb concentration of 100 ppb (parts per billion) in comparison to the pure ZnO and TiO2 nanoparticles. A superior response time (τres) of 13 s and recovery time (τrec) of 11 s are observed for ZT-1 sample with a high sensitivity response of 179 % is studied and therefore the nanocomposite material can be successfully utilized for acetone biomarker in diabetes.

Unique Cluster-Support Effect of a Co3O4/TiO2-3DHS Nanoreactor for Efficient Plasma-Catalytic Oxidation Performance.

For environmental catalysis, a central topic is the design of high-performance catalysts and advanced mechanism studies. In the case of the removal of flue gas pollutants from coal-fired power plants, highly selective nanoreactors have been widely utilized together with plasma discharge characteristics, such as the catalytic oxidation of NO. Herein, a novel reactor with a three-dimensional hollow structure of TiO2 confining Co3O4 nanoclusters (Co3O4/TiO2-3DHS) has been developed for plasma-catalytic oxidation of NO, whose performance was compared with that of the commercial TiO2 confining Co3O4 cluster (Co3O4/TiO2). Specifically, Co3O4/TiO2-3DHS presented a higher efficiency (almost 100%) within lower peak-peak voltage (VP-P). More importantly, the NO oxidation efficiency was between 91.5 and 94.5% after a long time of testing, indicating that Co3O4/TiO2-3DHS exhibits more robust sulfur and water tolerance. Density functional theory calculations revealed that such impressive performance originates from the unique cluster-support effect, which changes the distribution of the active sites on the catalyst surface, resulting in the selective adsorption of flue gas. This investigation provides a new strategy for constructing a three-dimensional hollow nanoreactor for the plasma-catalytic process.

Catalytic CO2 hydrogenation to produce methane over NiO/TiO2 composite: Effect of TiO2 structure

In this study, TiO2 was morphologically engineered into three distinct structures, namely three-dimensional microparticles (MPs), zero-dimensional nanoparticles (NPs) and one-dimensional nanowires (NWs) to examine the effect of structure on CO2 methanation. Firstly, thermodynamic analysis was conducted, whereby it was observed that CH4 production is favoured at low temperature. Higher temperature will cause the CH4 selectivity to drop, in turn increasing the formation of other side products such as CO, C2H6 and solid coke. Then, Ni loaded on three different TiO2 supports, namely 3D TiO2 microparticles (MPs), 0D nanoparticles (NPs) and 1D nanowires (NWs), were prepared. It was noticed that the NPs have the smallest support particle size, followed by NWs and MPs. Despite TiO2 NWs having a larger particle size than NPs, the 15% Ni/TiO2 NWs boasted a higher surface area, smaller NiO crystalline and particle size, which resulted in an augmented NiO dispersion. Superior CO2 methanation performance with CO2 conversion, CH4 yield and selectivity of 88.44%, 87.53% and 98.97%, respectively was achieved over 15% Ni/TiO2 NWs. The stability of the TiO2 NWs counterpart over a 40 hours reaction time was the best among the three samples. Spent catalyst analysis also indicated that 15% Ni/TiO2 NWs are highly resistant to catalyst deactivation and coke formation. The prolonged durability was attributed to the 1D wire-like structure, which promoted a higher dispersion of active sites, facilitating an intimate contact between catalyst and reactants. The ameliorated dispersion also mitigates catalyst deactivation via sintering and coke formation. The findings elucidated that the morphology of the catalyst is more influential in enhancing the hydrogenation reaction than the support size.

Crystalline S-doped TiO2 photoanodes from amorphous titanium oxysulfide (TiOxSy) for photo-oxidation reactions

S-doped TiO2 films were prepared by oxidation annealing of amorphous titanium oxysulfide (TiOxSy) at different temperatures. According to the X-ray diffraction patterns, the films calcined at temperatures of 300–600 °C showed only anatase phase, while the uncalcined sample was amorphous. The chemical composition of synthesized TiOxSy was estimated by X-ray photoelectron spectroscopy (XPS). High-resolution S 2p spectra showed S−2 bonds at 163.47 eV for the amorphous sample. The intensity of this signal decreased after heat treatment. Raman spectroscopy indicated an organization of the material structure with heat treatment of the material. Furthermore, optical characterization revealed that sulfur as dopant into the anatase TiO2 structure, shifted light absorption from ultraviolet to the visible region. Photoeletrochemical studies developed under polychromatic irradiation revealed superior photocurrents for samples calcined at 600 °C, with n-type behavior, adequate for photo-oxidation reactions.

Two-dimensional layered MoS2@CuS nanostructures decorated over TiO2 spheres for the decomposition of organic pollutant under visible light

A composite of MoS2/TiO2/CuS nanostructures was prepared by hydrothermal method. The structural and photocatalytic properties were investigated for the obtained composites. XRD patterns revealed the formation of hexagonal and anatase structure of MoS2, CuS and TiO2, respectively. XPS confirmed the chemical state of Mo, S, Cu, Ti and O, respectively. Morphological analysis revealed the formation of 2D layered MoS2 and CuS nanostructures on the surface of TiO2 spheres. The prepared MoS2/TiO2/CuS photocatalyst exhibited enhanced photocatalytic activity on the degradation of methylene blue (MB) (98.96 %) under visible light irradiation. The detailed photocatalytic mechanism explains the enhancement in the degradation efficiency.

Dual co-catalysts Ag/Ti3C2/TiO2 hierarchical flower-like microspheres with enhanced photocatalytic H2-production activity

Solar-powered semiconductor photocatalysis is considered a powerful strategy for addressing environmental pollution and energy crisis. Nevertheless, the separation and transfer abilities of photogenerated photocatalysts remain unsatisfactory. Herein, dual Ti3C2 nanosheets/Ag co-catalysts synergistically decorated hierarchical flower-like TiO2 microspheres for boosting photocatalytic H2 production were fabricated by electrostatic self-assembly and subsequent photoreduction procedures. The optimal Ag/Ti3C2/TiO2 composite demonstrated an excellent photocatalytic H2-production rate of 1024.72 μmol g−1 h−1 under simulated solar irradiation, achieving nearly 40, 2.3, and 1.8 folds with respect to that obtained on pristine TiO2, optimized Ti3C2/TiO2 composite, and Ag/TiO2 composite, respectively. The considerably improved photocatalytic H2-production activity is associated with the synergistic effect of the hierarchical flower-like structure of TiO2, excellent electrical conductivity of Ti3C2, and surface plasmon resonance effect of Ag, which enhances the light absorption capacity and promotes the separation and transfer of photogenerated carriers. This study provides insight into the design of high-efficiency photocatalysts with dual co-catalysts for solar H2 production.

Comparison of Electrospun Titania and Zinc Oxide Nanofibers for Perovskite Solar Cells and Photocatalytic Degradation of Methyl Orange Dye

ZnO and TiO2 are both well-known electron transport materials; however, an exact comparison of their performance, when fabricated under the same synthesis conditions, is missing in the literature. Considering this, we introduced a viable electrospinning route for the development of highly polycrystalline TiO2 and ZnO nanofibers for an electron transport material (ETM) of perovskite solar cells and photocatalysts for textiles. Thanks to the effective tuning of band structure and morphology of TiO2, a significant improvement in performance as compared to ZnO was observed when both were used as photoanodes and photocatalysts. X-ray diffraction detected polycrystalline structural properties and showed that peaks are highly corresponding to TiO2 and ZnO. Morphological analysis was carried out with a scanning electron microscope, which revealed that nanofibers are long, uniform, and polycrystalline, having diameter in the nano regime. TiO2 nanofibers are more aligned and electron-supportive for conduction as compared to ZnO nanofibers, which are dense and agglomerated at some points. Optoelectronic properties showed that TiO2 and ZnO show absorption values in the range of ultraviolet, and visible range and band gap values for TiO2 and ZnO were 3.3 and 3.2 eV, respectively. The TiO2 band gap and semiconductor nature was more compatible for ETL as compared to ZnO. Electrical studies revealed that TiO2 nanofibers have enhanced values of conductivity and sheet carrier mobility as compared to ZnO nanofibers. Therefore, a higher photovoltaic conversion efficiency and antibacterial activity was achieved for TiO2 nanofibers (10.33%), as compared to ZnO (8.48%). In addition, the antibacterial activity of TiO2 was also recorded as better than ZnO. Similarly, compared to ZnO nanofibers, TiO2 nanofibers possess enhanced photoactivity for antimicrobial and dye degradation effects when applied to fabrics.

Deciphering the role of (Er3+/Nd3+) co-doping effect on TiO2 as an improved electron transport layer in perovskite solar cells

Charge injection and transport at the interface of the electron transport layer (ETL) and perovskite interface are crucial for the perovskite solar cell (PSC) device performance. Titanium dioxide (TiO2) is well established as a photoanode in numerous solar energy conversion and storage. The bandgap engineering of TiO2 by Rare-Earth (RE)-doping has become a significant way to improve the optoelectronic device performance. This study demonstrates the improved performance of Rare-Earth doped TiO2 (RETO) photoanode based solar cells under the doping of Er3+, Nd3+ and following codoping of the (Er3+/Nd3+) effect. It is note that the Er, and Nd dopants are responsible for producing Ti3+ states and the oxygen vacancies near the surface, which drives the charge transportation much more effectively. With the (Er/Nd) codoping into TiO2, the band structure of TiO2 is modified better to make a quasi-Ohmic contact with the perovskites, by fermi level shifting as well changes in the conduction band minima (ECBM) energy states. This results evidence the preliminary conformation for the improvement of Jsc and Voc. Furthermore, the photoluminescence (PL) emission quenching effects of perovskite-deposited RETO attributes the suppression in the charge recombination. By insight into all these favourable results in the(Er3+/Nd3+) codoped TiO2, the RETO photoanode-based perovskite solar cell (PSC) devices were constructed and exhibited improved photovoltaic properties. The composition of (Er0.002Nd0.002Ti0.996O2) ETL employed PSC reported with a better photoconversion efficiency (PCE %) among all the compositions.

Photocatalytic activity and stability properties of porous TiO2 film as photocatalyst for methylene blue and methylene orange degradation

The development of photocatalyst material is strongly required to provide an efficient and effective photocatalyst with respect to photocatalytic activity performance, and also more specifically reusability. In this paper, we discuss the synthesis process of porous TiO2 film onto a glass substrate for photocatalyst with the assistance of doctor’s blade method coating which is considered as a simple and low-cost process. The porous TiO2 film with nanoparticle structure was then successfully deposited on the glass substrate. The FESEM results show the cross-section of porous TiO2 film on top of the glass substrate with a thickness of 25.05 µm and the nanoparticle size is around 100 nm, while EDS mapping shows the presence of titanium and oxygen without any impurities. Meanwhile, the anatase structure of porous TiO2 was confirmed by XRD and belongs to space group of I41/amd. The chemical bonding of Ti and O for porous TiO2 film has been analyzed using Raman shift and the highest active mode belongs 433 peak which shows the typical structure of TiO2 anatase. Meanwhile, UV-Vis analysis shows that the porous TiO2 has bandgap energy of ~3.2 eV. The photocatalyst result shows that porous TiO2 has reached 90% degradation process.

Photocatalytic degradation of bisphenol A in aqueous solution using TiO2/clinoptilolite hybrid photocatalyst.

Photocatalytic degradation of bisphenol A (BPA) was investigated using commercial TiO2 P25 nanoparticles supported on natural zeolite clinoptilolite (Cli). Employing ultrasound assisted solid-state dispersion method hybrid photocatalyst containing 20 wt% of TiO2, marked TCli-20, was prepared. The structural, morphological and surface properties, and particle size distribution of TCli-20 were studied by X-ray powder diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, scanning electron microscopy with energy dispersive spectroscopy, atomic force microscopy, Brunner-Emmet-Teller method and laser diffraction. The results revealed a successful loading of TiO2 P25 nanoparticles on Cli surface and the preservation of both zeolitic structure and optical properties of TiO2. The influence of catalyst dose, pH value and the addition of hydrogen peroxide (H2O2) was evaluated. The optimal reaction conditions were 2g/L of catalyst at near-neutral conditions (pH = 6.4) for complete BPA (5mg/L) photodegradation after 180min of exposure to simulated solar light. The addition of H2O2 was beneficial for the degradation process and led to the removal of BPA after 120min of irradiation. BPA removal (60% for 180min of irradiation) was reduced when TCli-20 was tested in bottled drinking water due to the presence of bicarbonate ions which acted as scavengers for hydroxyl radicals. Even though the photocatalytic activity of TCli-20 decreased after several cycles of usage, 70% of BPA was still successfully degraded during the fourth cycle. The reusability study showed easy separation, stability and good photocatalytic ability of investigated cost-effective hybrid photocatalyst.

Composites of TiO2 pillared sericite: Synthesis, characterization and photocatalytic degradation of methyl orange

A series of TiO2 pillared sericite nanocomposites were prepared by the sol-gel method followed by thermal treatment. Two factors, namely sericite dosage, and calcination temperature were researched to see their effects on the structure and properties of TiO2 pillared sericite nanocomposite. X-ray diffraction and nitrogen adsorption-desorption isotherms were used to analyze the changes of crystal phase, grain size and pore structure information of the generated TiO2 nanoparticles in the composite. Among all the samples, the TiO2 pillared sericite composite calcined at 800 °C has the best photocatalytic properties. Trapping experiment proved that the main active species are ·O2−, h+ and ·OH in order of participation during the photodegradation of methyl orange by the prepared composite. Sericite has a synergistic role in enhancing the photocatalytic activity of TiO2 pillared sericite nanocomposite. Good photocatalytic activity, together with its availability and good recyclability, makes sericite a promising substrate in the field of photocatalysis.

Oxygen vacancy engineering of TiO2 nanosheets for enhanced photothermal therapy against cervical cancer in the second near-infrared window

Cervical cancer is the most common and deadly female cancer on the worldwide scale. Considering that the conventional surgery treatment and chemotherapy would cause certain side effects, photothermal therapy (PTT) possesses desired therapeutic efficiency and insignificant side effects against cervical cancer. However, the lack of efficient and safe photothermal agents that operate in the second near-infrared (NIR-II) window is a main obstacle hindering the clinical transformation of PTT. Titanium dioxide (TiO2)-based nanomaterials are commonly applied in the biomedicine field, but the weak absorption and low photothermal conversion efficiency (PCE) of TiO2 in the NIR region limit their applications in PTT. Herein, we report the oxygen vacancy engineering that is a robust strategy to regulate the electronic structures of TiO2 for photothermal conversion properties optimizing. The obtained oxygen vacancy-doped TiO2−x nanosheets exhibit strong NIR-II absorption and high PCE owing to their decreased bandgap. Specifically, the PCE of TiO2−x nanosheets is determined to be 69.5 % in the efficient NIR-II window, which is much higher than that of widely reported PTT agents. Complete tumor recession without recurrence or pulmonary metastasis is realized by enhanced NIR-II PTT via TiO2−x nanosheets at an ultralow and safe laser exposure (0.6 W/cm2). Our findings suggest that oxygen vacancy engineering of nanomaterials could regulate their photothermal conversion performances, promoting the further application of TiO2-based nanomaterials in the biomedical.

UV Aydınlatma Altında Gelişmiş Fotokatalitik Performans için Fotokatalitik Biriktirme ile Hazırlanan Cu Nanokümelerle Süslenmiş Sütunlu TiO2 İnce Filmler

TiO2 photocatalyst is a promising material for different kinds of applications, including air and water purification, hydrogen production, and self-clean surfaces. It is usually combined with other materials to improve its charge separation as well as its activation under solar illumination. However, using such an approach is not suitable for practical photocatalytic applications because noble metals are too expensive. Therefore, cost-effective metals (e.g., copper, nickel, etc.) should be also considered instead of noble metals. In this study, we prepared photocatalytically active TiO2 thin films decorated with copper (Cu) nanoclusters (NCs) to improve the charge separation. Here, the metallic Cu NCs were deposited on TiO2 thin surface by a photocatalytic deposition process (under ultraviolet (UV) illumination). The morphology, size, and surface coverage of Cu NCs on TiO2 were varied by controlling the UV illumination time. Results showed that the optimum surface coverage (3.04 %) leads to a remarkable increase in photocatalytic performance compared to bare TiO2. However, depositing more Cu NCs with bigger sizes and higher surface coverage (7.08 %) decreased the overall photocatalytic activity. This might be due to the blocking of UV light incoming to the TiO2 thin film by bigger Cu NCs on the surface. The presented Cu-TiO2 hybrid system would be a good alternative to conventional co-catalyst systems which are composed of expensive metals (Au, Ag, Pt, etc.) and TiO2 structures.

Fe Doping in TiO2 via Anodic Dissolution of Iron: Synthesis, Characterization, and Electrophoretic Deposition on a Metal Substrate

The tailored physical properties of TiO2 are of significant importance in various fields and, as such, numerous methods for modifying these properties have been introduced. In this study, we present a novel method for doping Fe into TiO2 via the anodic dissolution of iron. The optimal conditions were determined to be an application of 200 V to acetylacetone (acac)/EtOH medium for 10 min, followed by the addition of TiO2 to the solution, sonication for 30 min, stirring at 80 °C, and drying. The resulting powder was calcined at 400 °C for 3 h, and characterization was conducted using XRD, FTIR, TEM, and UV-vis. The synthesized powder revealed the successful doping of Fe into the TiO2 structure, resulting in a decrease in the optical band gap from 3.22 to 2.92 eV. The Fe-TiO2 was then deposited on a metal substrate via the electrophoretic (EPD) technique, and the weight of the deposited layer was measured as a function of the applied voltage and exposure time. FESEM images and EDX analysis confirmed that the deposited layer was nanostructured, with Fe evenly distributed throughout the structure.

Enhanced photocatalytic oxidation of Sn/N co-doping TiO2 on As(III) under visible light

The photocatalytic oxidation technology has been verified as an effective method to oxidize As(III) to As(V) with low toxicity and the photocatalyst with perfect performances is still the core factor in the treatment procedure. In this paper, a high property photocatalyst of Sn/N co-doping TiO2 (Sn/N-TiO2) has been synthesized and applied to the photocatalytic oxidation of As(III). Through a series of characterization methods, it is proved that Sn and N atoms have been effectively doped into the crystal structure of TiO2, which makes the optical absorption wavelength of TiO2 extend from ultraviolet light to visible light region. At the same time, the presence of O-Ti-N bonds can offer an efficient electron moving path and further improve the photogenerated electron transfer rate, so as to enhance the photocatalytic oxidation effect. The synthesized Sn/N-TiO2 photocatalyst only takes 21 min to realize complete oxidation of As(III) (10,000 μg/L, 40 mL) to As(V) under visible light, superior to N-doped TiO2 (27 min) and Sn doped TiO2 (24 min) photocatalysts. The achievements of such efficient photocatalytic oxidation performances result from the synergistic interaction of hydroxyl radicals (·OH), superoxide radical (·O2–), and hole (h+) formed in the photocatalytic oxidation process and the O-Ti-N bond formed by co-doping. This paper provides a new insight for solving arsenic pollution by photocatalytic oxidation technology.

Impact of the duty cycle on the morphology and photocatalytic properties of S-TiO2 obtained by plasma electrolytic oxidation to treat real electroplating wastewater contaminated with Cr6+

This work reports S-TiO2 doped coatings to reduce Cr6+ to Cr3+ obtained from a Ti electrode through the Plasma Electrolytic Oxidation (PEO) process. The Ti sheets (20 × 20 × 1 mm) were submerged on 0.1 M H2SO4, and values of the duty cycle from 2% to 50% were applied to obtain various materials. SEM, XRD, AFM, XPS, and DRS techniques were used to characterize the resultant surfaces. It was observed that the duty cycle strongly influences the crystalline/amorphous ratio, anatase/rutile ratio, porosity density, pores size distribution, and surface roughness. Besides, it is explained that the introduction of SO42- into the TiO2 structure can take place either in the Ti or O places in the crystalline lattice. All materials showed photocatalytic properties to reduce Cr6+ to Cr3+ under UVC light (254 nm), decreasing the efficiency with the increase of the duty cycle. Additionally, the introduction of EDTA showed a positive synergy with the heterogeneous photocatalytic process when the material was obtained with the highest duty cycle. This last result was attributed to the relatively low bandgap and the high recombination rate; furthermore, EDTA acts as holes and hydroxyl radical scavenger. Thus, the photoelectrochemical system for the treatment of wastewater was evaluated, and again, the same materials showed the highest performance. In the same way, the re-use of the material obtained with the 2% duty cycle was tested, getting satisfactory results, obtaining 96.14 ± 2.77% Cr6+ reduction even after seven cycles of reuse.

Tailoring Black TiO2 Thin Films: Insights from Hollow Cathode Hydrogen Plasma Treatment Duration

In this study, we report the use of a radiofrequency plasma-assisted chemical vapor deposition (RF-CVD) system with a hollow cathode geometry to hydrogenate anatase TiO2 thin films. The goal was to create black TiO2 films with improved light absorption capabilities. The initial TiO2 was developed through magnetron sputtering, and this study specifically investigated the impact of hollow cathode hydrogen plasma (HCHP) treatment duration on the crucial characteristics of the resulting black TiO2 films. The HCHP treatment effectively created in-bandgap states in the TiO2 structure, leading to enhanced light absorption and improved conductivity. Morphological analysis showed a 24% surface area increase after 15 min of treatment. Wettability and surface energy results displayed nonlinear behavior, highlighting the influence of morphology on hydrophilicity improvement. The anatase TiO2 phase remained consistent, as confirmed by diffractograms. Raman analysis revealed structural alterations and induced lattice defects. Treated samples exhibited outstanding photodegradation performance, removing over 45% of methylene blue dye compared to ~25% by the pristine TiO2 film. The study emphasized the significant impact of 15-min hydrogenation on the HCHP treatment. The research provided valuable insights into the role of hydrogenation time using the HCHP treatment route on anatase TiO2 thin films and demonstrated the potential of the produced black TiO2 thin films for photocatalytic applications.

Pair distribution function analysis for oxide defect identification through feature extraction and supervised learning

Feature extraction and a neural network model are applied to predict defect types and concentrations in experimental anatase TiO2 samples. A dataset of TiO2 structures with vacancies and interstitials of oxygen and titanium is built, and the structures are relaxed using energy minimization. The features of the calculated pair distribution functions (PDFs) of these defected structures are extracted using linear methods (principal component analysis and non-negative matrix factorization) and non-linear methods (autoencoder and convolutional neural network). The extracted features are used as inputs to a neural network that maps feature weights to the concentration of each defect type. The performance of this machine learning pipeline is validated by predicting defect concentrations based on experimentally measured TiO2 PDFs and comparing the results to brute-force predictions. A physics-based initialization of the autoencoder has the highest accuracy in predicting defect concentrations. This model incorporates physical interpretability and predictability of material structures, enabling a more efficient characterization process with scattering data.

Titanium (IV) oxide composite hollow nanofibres with silver oxide outgrowth by combined sol–gel and electrospinning techniques and their potential applications in energy and environment

A two-dimensional nanostructure composed of Ag2O nanobranches attached to TiO2 hollow nanofibres (denoted as 2D Ag2O/TiO2) was successfully prepared via sol–gel and coaxial electrospinning techniques. The Ag/TiO2 hollow nanofibres were fabricated and calcined in ambient air at 500 °C. By calcination, the removal of organic materials and the formation of anatase TiO2 were achieved with a well-retained hollow structure. The embedded Ag nanoparticles functioned as seeds for the Ag2O outgrowth on the TiO2 surface using a hydrothermal treatment at different times and temperatures, which caused the change in physical appearance, surface area, and electrical conductivity of 2D Ag2O/TiO2. A high quantity of Ag2O nanobranches on TiO2 nanofibres were obtained with increasing the temperature from 110 to 115 °C and the reaction time to 60 min. Consequently, the electrochemical active surface area (EASA) value was maximised to 65.25 cm2 per cm2 with an enhanced electrical conductivity of 91.3 ± 3.9 × 10−2 S cm−1. Further studies on the depth-profiles of Ag, Ti, and O revealed the presence of Ag2O attached to the core structure of TiO2. The photoelectrochemical and photocatalytic tests confirmed the excellent physical and electrochemical properties of 2D Ag2O/TiO2 (@115 °C, 60 min) for use in energy and environmental applications.Graphical