Synthesis Of TiO2 Research Articles

Novel Anodic TiO2 Synthesis Method with Embedded Graphene Quantum Dots for Improved Photocatalytic Activity

Photocatalytic degradation of pollutants have a high potential for sustainable and renewable uses. TiO2 is a widely studied photocatalyst due to its high chemical and photochemical stability and wide range of applications. However, the wide band gap and low capacity of photo-induced charge separation provide lower catalytic activity; thus, improvement of these properties must be found. The doping of TiO2 with other elements, such as carbon nanoparticles (CNP) in a quantum dot form, offers a promising pathway to improve the aforementioned properties. In addition, in situ doping methods should be investigated for practical scalability, as they offer the advantage of integrating dopants directly during material synthesis, ensuring a more uniform distribution and better interaction between the dopant and the host material, in turn leading to more consistent photocatalytic properties. Current technologies primarily involve nanoparticle combinations. This work focuses on the development of a novel in situ synthesis methodology by the introduction of three different graphene-based quantum nanodots into anodic TiO2 and the following investigation of structural, morphological, and photocatalytic properties. Results indicate that the introduction of CNP allows for the shift of a set of parameters, such as the optical band gap, increased photo-induced charge carrier density of TiO2/CNP composite, and, most importantly, the change of crystalline phase composition depending on added CNP material. Research indicates that not only a higher concentration of added CNP enhances higher photocatalytic activity as tested by the degradation of methylene blue dye, but also the type of CNP determines final crystalline phase. For the first time brookite and rutile phases were obtained in anodic titania synthesized in inorganic electrolyte by introducing hydrothermally treated exfoliated graphene.

A New Wax Gourd (Benincasa hispida (Thunb.) Cogn.)‐Assisted Green Synthesis Method of Metal Oxides (TiO2, MgO)

AbstractIn the reaction environment of wax gourd extract, titanium dioxide (TiO2) and magnesium oxide (MgO) were synthesized by microemulsion method. Under atmospheric pressure, the optimum conditions for preparing TiO2 and MgO nanoparticles were investigated at different reaction temperatures and time. The obtained optimal reaction conditions are as follows: when the amount of TiCl3 solution was 70 µL, the mass ratio of wax gourd extract to water was 1:2, the reaction time was 60 min, and the reaction temperature was 35 °C, rod‐like TiO2 particles with the best dispersion and crystallinity were obtained. When the amount of MgCl2 solution was 10 mL, the amount of wax gourd extract was 40 mL, the reaction time was 120 min, and the reaction temperature was 70 °C, the prepared MgO particles exhibited a spindle shape with the best dispersion and crystallinity. Wax gourd‐assisted synthesis of TiO2 and MgO provides not only a new synthesis idea for the preparation of metal oxides, but also a green environmental protection system, which conforms to the concept of sustainable development.

The role of synthesizing time on the optoelectronic properties of TiO2-ZnO nanocomposite on PTFE substrate fabricated by the chemical bath deposition method

ZnO-based ultraviolet photodetectors have been employed in advanced applications, including environmental monitoring, space exploration, and secured optical communication. In this work, TiO2-ZnO nanocomposite that included Ti-doped ZnO nanorods was synthesized using chemical bath deposition method at 96 °C on PTFE substrates for ultraviolet photodetectors. ZnO nanorods grew for 3 hours, followed immediately by the synthesis of TiO2 for 2 hours. The characterizations revealed several distinguished structural, optical, and electrical properties compared with reference ZnO-only samples deposited for 3 h and 5 h respectively. The indirect band gap of the produced nanocomposite was 3.09 eV. The fabricated ultraviolet photodetector revealed outstanding results: a responsivity of 673.667 mA/W, a detectivity of 5.121×108 Jones, and an external quantum efficiency of 229.44%. The results showed the potential of the nanocomposite for photodetector applications on flexible substrate.

Breaking New Grounds: solid-state synthesis of TiO2 – La2O3 – CuO Nanocomposites for degrading Brilliant Green dye under Visible Light

Environmental pollution, particularly from industrial dyes and chemicals, poses a significant threat to ecosystems and human health. Traditional pollution mitigation methods are often inefficient and costly. Photocatalysis has emerged as a promising solution for degrading pollutants using light energy. Titanium dioxide (TiO2) is a widely studied photocatalyst due to its stability, non-toxicity, and strong oxidative power. However, its efficiency is limited by a wide bandgap, restricting absorption to the UV region, and rapid electron-hole recombination. To address these limitations, doping TiO2 with materials like La2O3 and CuO has been explored to enhance its photocatalytic activity under visible light. This study investigates the enhancement of TiO2 nanocomposites by incorporating La2O3 and CuO. X-ray diffraction (XRD) revealed that the nanocomposites retained TiO2's anatase and rutile phases with improved crystallinity. Scanning electron microscopy (SEM) displayed spherical nanoparticles forming agglomerates, typically due to high surface energy. Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) confirmed the presence of La and Cu in the TiO2 matrix. Fourier-transform infrared (FTIR) spectroscopy identified characteristic vibrational modes of Ti–O, La–O, and Cu–O bonds, suggesting strong chemical interactions between dopants and TiO2 lattice. Ultraviolet-visible (UV-Vis) spectroscopy showed a red shift in absorption spectra with La2O3 and CuO addition, reducing the bandgap energy from 3.23 eV (pure TiO2) to 2.27 eV for the TiO2–0.1La2O3–0.2CuO composite. Photoluminescence (PL) spectroscopy indicated improved charge separation and reduced electron-hole recombination rates in the synthesized nanocomposites. Photocatalytic performance was evaluated by degrading Brilliant Green (BG) dye under visible light. The TiO2–0.1La2O3–0.2CuO (TLC0.2) nanocomposite achieved a maximum dye degradation of over 95% after 204 minutes under optimal conditions (C0 = 17 mg/L and a S/L ratio of 1 g/L). Adding the inorganic agent Na2SO4 to this process significantly enhanced photocatalytic activity, increasing degradation from 56% to 95% after 180 min of visible light irradiation under C0 = 20 mg/L and S/L = 0.5 g/L conditions, as it shows a high stability after six reuse cycles. In conclusion, La2O3 and CuO doping significantly enhance TiO2 nanocomposites' crystalline structure, morphology, optical properties, and photocatalytic efficiency, demonstrating their potential for environmental remediation and solar energy conversion.

Review of Bio-Inspired Green Synthesis of Titanium Dioxide for Photocatalytic Applications

Titanium dioxide (TiO2) is an important photocatalyst that is widely studied for environmental applications, especially for water treatment by degradation of pollutants. A range of methods have been developed to produce TiO2 in the form of nanoparticles and thin films. Solution-based synthesis methods offer the opportunity to tune the synthesis through a choice of reagents, additives and reaction media. In particular, the use of biomolecules, such as proteins and amino acids, as bio-inspired additives in TiO2 synthesis has grown over the last decade. This review provides a discussion of the key factors in the solution-based synthesis of titania, with a focus on bio-inspired additives and their interaction with Ti precursors. In particular, the role of bio-inspired molecular and biomolecular additives in promoting the low-temperature synthesis of titania and controlling the phase and morphology of the synthesised TiO2 is discussed, with a particular focus on the interaction of TiO2 with amino acids as model bio-inspired additives. Understanding these interactions will help address the key challenges of obtaining the crystalline TiO2 phase at low temperatures, with fast kinetics and under mild reaction conditions. We review examples of photocatalytic applications of TiO2 synthesised using bio-inspired methods and discuss the ways in which bio-inspired additives enhance photocatalytic activity of TiO2 nanomaterials. Finally, we give a perspective of the current challenges in green synthesis of TiO2, and possible solutions based on multi-criteria discovery, design and manufacturing framework.

Synthesis and Characterization of TiO2 -CQDs Nanocomposites and Testing of Their Anticancer Potential

This work used a green approach to produce carbon quantum dots (CQDs). TiO2 nanoparticles (NPs) and TiO2–CQDs nanocomposites with different weight ratios of CQDs were organized through a facile sol-gel method. XRD showed that the anatase and rutile phases of TiO2 were polycrystalline with a tetragonal structure and that the CQDs exhibited a broad peak at (002) and a hexagonal structure. High resolution-transmission-electron microscopy revealed that the TiO2 NPs agglomerated in mostly spherical shapes and that the anatase and rutile phases of TiO2 had sizes of less than 15 and 25 nm, respectively. The CQDs had a relatively uniform diameter, a spherical shape with a highly crystalline structure, and a size below 2 nm. UV–visible spectroscopy revealed that the absorbance of the TiO2- CQDs nanocomposites increased with the increase in CQD ratio. The energy band gaps of the anatase and rutile phases were 3.07 and 2.7 eV, respectively, whereas that of CQDs was 3.14 eV. Meanwhile, the energy band gaps of the TiO2–CQDs nanocomposites decreased with the increase in CQDs ratio. The growth inhibition rates of the liver cancer HepG2 cell line and the normal cell line RD were measured after 24 hours of experience to the two TiO2 phases and TiO2–CQDs nanocomposites. The cytotoxicity test presented that the tested substances were extremely harmful to cells in cancer. Inhibition rates increased with the increase in CQDs ratio. The inhibition rate of growth in cancer cells, including the liver cancer HepG2 cell line and the normal cell line (RD), was measured for 24 hours after they were exposed to TiO2 (two phases) and TiO2-CQDs nanocomposites. The samples showed a slight effect on the normal line (RD) compared to HepG2 cancer. The highest inhibition rate was 12.11% for the CQD 0.7 sample.

Crystallization of 2D TiO2 Nanosheets via Oriented Attachment of 1D Coordination Polymer.

Demystifying the molecular mechanism of growth is vital for the rational design, synthesis, and optimization of functional nanomaterials. Despite the promising perspectives and extensive efforts, the growth mechanism of atomically thin TiO2(B) nanosheets remains unclear, hence it is difficult to tune their band and surface structures. Herein, we report an oriented attachment-based crystallization mechanism of TiO2(B) nanosheets from a 1D titanium glycolate coordination polymer through hydrolysis and condensation. With time-tracking experiments, this 1D coordination polymer is found to be an intermediate in the synthesis of TiO2(B) nanosheets by using Ti alkoxides and chlorides as precursors, suggesting the universality of the 1D-to-2D growth mechanism. Such a side-to-side attachment pathway bridges the classical and nonclassical interpretations of crystallization, and meanwhile hints at the possibility of other 1D complexes as potential precursors for 2D materials.

A study on bacterial inactivation using green synthesized photocatalytically active TiO2, MgO, TiO2/MgO nanoparticles

Madhuca longifolia (Mahua) flower extracts were utilised to perform the green synthesis of titanium dioxide (TiO2), magnesium oxide (MgO) nanoparticles, and a nanocomposite consisting of TiO2/MgO. Mahua flower extracts were used as both reducing and capping agents in a sol-gel synthesis method. The effectiveness of the green reducing agent in improving the surface structure of the green nanoparticles was demonstrated. FTIR, XRD, FESEM, and UV vis spectroscopy were employed to analyse the successful synthesis of TiO2, MgO, and TiO2/MgO nanocomposites. A study was done to examine the process of employing these nanoparticles to deactivate Escherichia coli (E. coli) by photocatalysis. The effectiveness of these nanoparticles in inhibiting the growth of the bacterial species was demonstrated. The optimisation of the bacterial inactivation experiment was performed using Design Expert's RSM CCD model on all three nanoparticle samples. The optimisation study investigated the impact of nanoparticle concentration and exposure duration on the inhibition of bacterial growth. The highest levels of percent inhibition (%I) were recorded as 85.4 % for TiO2/MgO, 82.8 % for TiO2, and 65.14 % for MgO at a concentration of 50 mg/2 ml and an exposure time of 2 h. The effectiveness of these nanoparticles in exhibiting inhibition has been limited, indicating their prospective use in the advancement of antimicrobial coatings and other applications, such as disinfectants, in the future.

Synthesis, Magnetic, and Photocatalytic Activity of Polypyrrole-Based TiO2–Fe Catalyst for Wastewater Treatment

The primary aim of this study is to investigate the degradation efficacy of the Ppy/TiO2-Fe photocatalyst for MB dye in an aqueous solution. Firstly, the direct addition of TiO2 and Fe was done to prepare Ppy/TiO2-Fe photocatalyst. Fourier transformation infrared spectroscopy, XRD, SEM, BET surface area analysis, and magnetization tests established the formation of the Ppy/TiO2-Fe photocatalyst. The crystallite sizes of TiO2, Fe-TiO2, and Ppy/TiO2-Fe photocatalyst were estimated to be 24.99 nm, 21.94 nm, and 21.84 nm, respectively. For the synthesis confirmation, the FTIR spectrum confirmed the existence of Ti-O, Fe-O, and Ppy-related bonds. While comparing the SEM images, the impact of polypyrrole on the particle shape was observed with less aggregation and increased surface roughness. The VSM analysis revealed that incorporating polypyrrole (Ppy) into Fe-TiO2 significantly enhances its magnetic properties, with Ppy/TiO2-Fe exhibiting superparamagnetic behavior, characterized by a higher saturation magnetization (Ms) of 33.11 emu/g and a lower coercivity (Hc) of 0.160 Oe, compared to Fe-TiO2’s Ms of 1.09 emu/g and Hc of 341.39 Oe. The N2 sorption desorption, with a specific surface area of 2.25 × 102 m2/g, is beneficial for photocatalytic activity. The concentration of dye, amount of catalyst, pH, and temperature were studied to evaluate the photocatalytic efficiency of the synthesized Ppy/TiO2-Fe photocatalyst under different conditions. The findings revealed a degradation efficiency of 91.92%. The degradation rate reached 91.92% under optimal conditions within 120 min and could be fitted well by first-order kinetics. The photocatalytic efficiency was also evaluated for the scavenger, and the concentration of H2O2 and the reusability of the catalyst were demonstrated. Based on the observed results, the Ppy/TiO2-Fe photocatalyst could be applied more effectively and efficiently to photocatalytic degradation of organic dyes in wastewater treatment.

Charge carrier dynamics of chemical vapor deposited carbon-doped titanium dioxide photoanodes

This study explores the synthesis of carbon-doped titanium dioxide TiO2(C) photoanodes through a single-step, low-pressure chemical vapor deposition (LCPVD) method, investigating the influence of carbon doping and oxygen vacancies on photoelectrochemical performance. The research employs morphological, structural, and photoelectrochemical characterization methods, including intensity-modulated photocurrent spectroscopy (IMPS) and distribution of relaxation times (DRT) analysis. We correlate the simultaneous presence of surface carbon and oxygen defects to improved charge separation and collection for TiO2(C) photoanodes. This work provides a comprehensive and detailed explanation of the photoelectrochemical performance of TiO2 electrodes, showing the potential behind combined IMPS-DRT analysis for photoelectrode characterization.

Green synthesis and characterization of TiO2 and Ag-doped TiO2 nanoparticles for photocatalytic and antimicrobial applications

TiO2 and Ag-doped TiO2 nanoparticles were synthesized using lemon grass plant leaf extract via a greener co-precipitation method. Plant biomolecules facilitated nanoparticle production, ensuring stability. Characterization involved XRD, FE-SEM, XPS, FT-IR, EDX, UV-DRS, HR-TEM and UV–Vis spectroscopy analyses, revealing tetragonal and cubic structures for TiO2 and Ag-TiO2, with average sizes of 11.96 and 41.8 nm, respectively. FT-IR confirmed characteristic bands, FE-SEM and HR-TEM analysis reveal that Ag-doped TiO2 nanoparticles primarily form irregular agglomerations, with interplanar spacings of 0.362 nm for the anatase (220) plane and 0.235 nm for the silver (111) plane and EDX determined elemental composition. UV–DRS calculated band gap values (3.3 eV for TiO2, 0.9 eV for Ag-TiO2). Photocatalytic performance against methylene blue dye under sunlight indicated higher degradation by Ag-TiO2 (96.96 %) than TiO2 (77.77 %). Antimicrobial testing showed superior activity of Ag-TiO2 over TiO2.

Optimizing the green synthesis of antibacterial TiO2 - anatase phase nanoparticles derived from spinach leaf extract

Titanium dioxide nanoparticles, renowned for their abundance, non-toxicity, and stability, have emerged as indispensable components in various fields such as air purification, healthcare, and industrial processes. Their applications as photocatalysts and antibacterial agents are particularly prominent. The synthesis methods significantly influence the properties and subsequent applications of these nanoparticles. While several techniques exist, the biological approach using plant extracts offers advantages such as simplicity, biocompatibility, and cost-effectiveness. This study focused on the green synthesis of titanium dioxide nanoparticles utilizing spinach leaf extract. Within the scope of this investigation, the green synthesis of titanium dioxide nanoparticles through spinach leaf extract were synthesized and optimized, followed by a comprehensive examination of their morphological, structural, and chemical attributes with UV-visible spectroscopy, FTIR spectroscopy, XRD, FESEM, and EDX. The minimum inhibitory concentration (MIC) against E. coli and S. aureus was determined to evaluate their antibacterial potential. Optimal synthesis conditions were identified at 50 °C, using a 1/30 concentration and 20 ml of spinach leaf extract. Spherical anatase nanoparticles, ranging from 10 to 40 nm, were produced under these conditions. The change in the color of the extract, absorption at 247 nm, change and increase of the peak at 800 − 400 wavelengths, and the maximum intensity of X-ray diffraction at the angle of 25.367 with the crystal plane 101 were indications of the synthesis of these nanoparticles. Notably, the synthesized nanoparticles exhibited antibacterial activity with MIC values of 0.5 mg/ml against E. coli and 2 mg/ml against S. aureus. This research presents a novel, eco-friendly approach to synthesizing titanium dioxide nanoparticles with promising antibacterial properties.

The synthesis of TiO2 using a nanocrystalline cellulose template improves its photocatalytic performance

Using cellulose nanocrystals (CNCs) as a template in the production of TiO2 has a positive impact on its crystal and porous structure, ultimately improving its photocatalytic performance. In this study, TiO2 photocatalysts with mesoporous anatase structures were prepared by acid-catalyzed hydrolysis using sulfate-ester-modified CNCs as the template. The effects of CNC concentration on the structure and performance of TiO2 were investigated in detail. The addition of CNCs was found to inhibit TiO2 transformation from the anatase to rutile phase, and abundant hydroxyl and sulfate ester groups on the CNCs provide narrow confined spaces for the crystal growth of TiO2, leading to the generation of smaller crystals with more exposed (001) crystal faces. Moreover, the CNCs act as a template for the pore structure remaining after calcination, thus increasing the specific surface area of the TiO2. Among the numerous samples evaluated, that prepared with a CNC concentration of 0.15 wt% and calcined at 600 °C had the highest percentage of (001) crystalline surface exposure. In photodegradation tests using phenol as a model pollutant, a degradation rate of 97.4 % and mineralization rate of 79.9 % were achieved with 60 min of light exposure. Thus, this study provides a clear approach for the directional synthesis of mesoporous TiO2 from biomass template materials.

Controllable synthesis of TiO2/graphene composites for human voice recognition in strain sensor.

Low-dimensional materials have demonstrated strong potential for use in diverse flexible strain sensors for wearable electronic device applications. However, the limited contact area in the sensing layer, caused by the low specific surface area of typical nanomaterials, hinders the pursuit of high-performance strain-sensor applications. Herein, we report an efficient method for synthesizing TiO2-based nanocomposite materials by directly using industrial raw materials with ultrahigh specific surface areas that can be used for strain sensors. A kinetic study of the self-seeded thermal hydrolysis sulfate process was conducted for the controllable synthesis of pure TiO2 and related TiO2/graphene composites. The hydrolysis readily modified the crystal form and morphology of the prepared TiO2 nanoparticles, and the prepared composite samples possessed a uniform nanoporous structure. Experiments demonstrated that the TiO2/graphene composite can be used in strain sensors with a maximum Gauge factor of 252. In addition, the TiO2/graphene composite-based strain sensor showed high stability by continuously operating over 1,000 loading cycles and aging tests over three months. It also shows that the fabricated strain sensors have the potential for human voice recognition by characterizing letters, words, and musical tones.

Scalable Synthesis of Bulk TiO2 Hybrids and Its Li-Storage Properties in “Rocking-Chair” Type Full-Cell Assembly with LiNi0.5Mn1.5O4 Cathode

TiO2 as an anode material in lithium-ion batteries (LIB) has abolished hurdles like irreversibility, cycling stability, rate capability, and energy density, which are vital for electrochemical performance. Conventionally, time-consuming and complex techniques like solvothermal methods are employed to synthesize TiO2. We herein open a new avenue towards a simple, scalable, and eco-friendly synthesis of bulk TiO2 anatase/bronze hybrids from sodium meta-titanate through a facile mechano-chemical and ion-exchange process under different temperature conditions (400, 450, and 500 °C). Structural and morphological features are analyzed through various characterization techniques such as XRD, FE-SEM, HR-TEM, and XPS. The bronze phase’s high reversibility, low redox potential, high current rate performance, and high power capability of the anatase phase make the hybrid attractive for fabricating high power and high energy density Li-ion power packs. The Li insertion/extraction properties are studied in half-cell assembly (Li/TiO2), where all three TiO2 hybrids exhibited promising results with an initial discharge capacity >165 mAh g-1 at a current rate of 0.05 A g-1 along with a capacity retention >90% after 100 cycles. A “rocking-chair” type full-cell configuration with high voltage LiNi0.5Mn1.5O4 cathode is fabricated, in which LNMO/TiO2-400 °C displayed a discharge capacity of ~88 mAh g-1 at a current rate of 0.05 A g-1. Moreover, the full cell exhibited a capacity retention of >70% after 100 cycles with a maximum energy density of 192.75 Wh kg-1. Figure 1

Optimisation of TiO2 synthesis from ilmenite sand and its application in the photocatalytic process

ABSTRACT Iron sand, a mineral, can be extracted to produce titanium dioxide (TiO2). TiO2 is a semiconductor material that is commonly used in photocatalytic applications, as well as electronics, colour pigments, paint manufacturing, and semiconductors. In this study, TiO2 was extracted from Banten ilmenite sand using caustic fusion and hydrometallurgical methods. The TiO2 extraction process was carried out by varying the mole ratio of ilmenite sand to NaOH, which was 1:0, 1:3, and 1:5, and the fusion temperatures were 700°C and 850°C, with time variations of 30, 60, and 90 min. XRF analysis revealed that the highest TiO2 composition was 91.64% in samples with a mole ratio of 1:3 during 30 min of fusion time and 91.14% in samples with a mole ratio of 1:5 during 90 min of fusion time. The XRD data revealed that TiO2 has a rutile phase with a tetragonal structure, while scanning electron microscopy (SEM) analysis revealed that the particle distribution in the sample is not uniform. The UV-Vis measurements revealed that TiO2 has a band gap of 3.10 at 700°C and 3.13 at 850°C. Furthermore, TiO2 degraded Rhodamine B dyes at a rate of 28.266%.

2D TiO2 Nanosheets Decorated Via Sphere-Like BiVO4: A Promising Non-Toxic Material for Liquid Phase Photocatalysis and Bacterial Eradication.

An in-depth investigation was conducted on a promising composite material (BiVO4/TiO2), focusing on its potential toxicity, photoinduced catalytic properties, as well as its antibiofilm and antimicrobial functionalities. The preparation process involved the synthesis of 2D TiO2 using the lyophilization method, which was subsequently functionalized with sphere-like BiVO4 through wet impregnation. Finally, we developed BiVO4/TiO2 S-scheme heterojunctions which can greatly promote the separation of electron-hole pairs to achieve high photocatalytic performance. The evaluation of concentration- and time-dependent viability inhibition was performed on human lung carcinoma epithelial A549 cells. This assessment included the estimation of glutathione levels and mitochondrial dehydrogenase activity. Significantly, the BiVO4/TiO2 composite demonstrated minimal toxicity towards A549 cells. Impressively, the BiVO4/TiO2 composite exhibited notable photocatalytic performance in the degradation of rhodamine B (k=0.135 min-1) and phenol (k=0.016 min-1). In terms of photoinduced antimicrobial performance, the composite effectively inactivated both gram-negative E. coli and gram-positive E. faecalis bacteria upon 60 minutes of UV-A light exposure, resulting in a significant log 6 (log 10 CFU/mL) reduction in bacterial count. In addition, a 49 % reduction of E. faecalis biofilm was observed. These promising results can be attributed to the unique 2D morphology of TiO2 modified by sphere-like BiVO4, leading to an increased generation of (intracellular) hydroxyl radicals, which plays a crucial role in the treatments of both organic pollutants and bacteria. This research has significant potential for various applications, particularly in addressing environmental contamination and microbial infections.

Fabrication of multifunctional wool textile using the synthesis of silver-modified N-doped ZnO/TiO2 photocatalysts

Photocatalysts and noble metals have attracted considerable attention for their potential in addressing global environmental pollution through photochemical processes. At low temperatures, multifunctional self-cleanable wool fabric was developed through green photo-sonosynthesis of N–Ag/TiO2/ZnO. A narrower bandgap of the hybrid photocatalyst, the surface plasmonic resonance effect of silver nanostructures, and nitrogen doping resulted in synergistically enhanced self-cleaning activity. The self-cleaning activity was evaluated by monitoring the discoloration of methylene blue stains on the wool fabric exposed to natural sunlight, using CIELAB color space and ΔE measurements. The ΔE value of the N–Ag/TiO2/ZnO-sonicated wool was superior, showing a value of 45.9 compared to 15.7 for the control and 28.7 for the sample coated by the stirrer. Furthermore, the nanocomposite construction improved tensile strength, enhanced fabric hydrophilicity, and reduced the yellowness index. Additionally, the synthesis of TiO2 and silver particles on ZnO particles increased surface resistance to acid, reducing ZnO acid solubility. The reflectance of the non-treated wool ranged from 5 to 20 % within 200–380 nm, while the reflectance of the Ag/TiO2/ZnO-sonicated sample remained constant at 4 %, exhibiting protection against UV rays. AATCC test revealed 100 % bacteria reduction against E. coli and S. aureus and 99 % against C. albicans fungus for N–Ag/TiO2/ZnO-sonicated sample. Moreover, cell culture assays demonstrated a viability of over 70 %, indicating non-cytotoxicity.

Sol-Gel Synthesis of TiO2 with Pectin and Their Efficiency in Solar Cells Sensitized by Quantum Dots.

In this study, titanium oxide TiO2 nanoparticles were produced using the sol-gel approach of green synthesis with pectin as the reducing agent. The synthetized TiO2 nanoparticles with pectin were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), visible light absorption (UV-Vis) and the BET method. The structure and morphology of the TiO2 powder were described with SEM, revealing uniform monodisperse grains with a distribution of 80% regarding sizes < 250 nm; the resulting crystal phase of synthetized TiO2 was identified as an anatase and rutile phase with a crystallinity size estimated between 27 and 40 nm. Also, the surface area was determined by nitrogen adsorption-desorption using the Brown-Emmet-Teller method, with a surface area calculated as 19.56 m2/g, typical of an IV type isotherm, indicating mesoporous NPs. UV-Vis spectra showed that sol-gel synthesis reduced the band gap from the 3.2 eV common value to 2.22 eV after estimating the optical band gap energy using the adsorption coefficient; this translates to a possible extended photo response to the visible region, improving photoactivity. In addition, the power conversion of the photoelectrode was compared based on similar assembly techniques of TiO2 electrode deposition. Quantum dot crystals were deposited ionically on the electrode surface, as two different paste formulations based on a pectin emulsifier were studied for layer deposition. The results confirm that the TiO2 paste with TiO2-synthesized powder maintained good connections between the nanocrystalline mesoporous grains and the deposited layers, with an efficiency of 1.23% with the transparent paste and 2.27% with the opaque paste. These results suggest that pectin could be used as a low-cost, functional sol-gel catalysis agent for the synthesis of controlled NPs of metal oxide. It demonstrates interesting optical properties, such as an increase in photo response, suggesting further applications to photocatalysts and biomedical features.

Synthesis of Mesoporous Tetragonal ZrO2, TiO2 and Solid Solutions and Effect of Colloidal Silica on Porosity.

Metal oxides possessing a large surface area, pore volume and desirable pore size provide more varieties and active industrial potentials. Nevertheless, it is very challenging to produce crystal metal oxides while keeping satisfactory porosity features, especially for ternary compositions. High temperature is usually needed to produce crystal metal oxides, which readily leads to the collapse of the pore structure. Herein, by employing a 'soft' dispersant agent and a hard silica template, ZrO2, TiO2 and Zr-Ti solid solutions having a tetragonal crystal structure are produced and the silica-leached materials are characterized from macroscopic to atomistic scales. The micron-sized particulate powders are composed of nanoscale 'building blocks', with crystallite sizes between ~8 and 21 nm. These polycrystalline ceramic powders exhibit a high specific surface area (up to ~200 m2·g-1) and pore volume (up to 0.5 cm3·g-1), with a pore size range of ~5-20 nm. Importantly, the Zr/Ti-O-Si-OH chemical bonds exist on the particle surface, with about two-thirds of the surface covered by silica. The hydroxyl groups can further post-graft organic ligands or directly associate with species. Synthesized mesoporous metal oxides are highly homogenous and could potentially be used in various applications because of their tetragonal structure and porosity features.