TiO2 Nanoparticles Research Articles

An Electrochemical Sensor for Detection of Lead (II) Ions Using Biochar of Spent Coffee Grounds Modified by TiO2 Nanoparticles

Toxic heavy metal ions, such as lead ions, significantly threaten human health and the environment. This work introduces a novel method for the simple and sensitive detection of lead ions based on biochar-loaded titanium dioxide nanoparticles (BC@TiO2NPs) nanocomposites. Eco-friendly biochar samples were prepared from spent coffee grounds (500 °C, 1 h) that were chemically activated with TiO2 nanoparticles (150 °C, 24 h) to improve their conductivity. Structural characterizations showed that BC@TiO2NPs have a porous structure. The BC@TiO2NPs material was evaluated for lead ion determination by assembling glassy carbon electrodes. Under optimal conditions, the sensor was immersed in a solution containing the analyte (0.1 M NaAc-HAc buffer, pH = 4.5) for the detection of lead ions via differential pulse voltammetry. A linear dynamic range from 1 pM to 10 μMwas achieved, with a detection limit of 0.6268 pM. Additionally, the analyte was determined in tap water samples, and a satisfactory recovery rate was achieved.

Remediation of Ni2+ and Sr2+ ions from aqueous solutions by acacia gum/polyacrylic acid hydrogel reinforced with TiO2 nanoparticles

Abstract Globally, the environment and public health are progressively threatened due to water resource contaminants. For this purpose, a unique polyfunctional nanocomposite is created to remediate heavy metals from aqueous media. The basis of it is TiO2 composite nanoparticles (NPs) manufactured via embedding titanium oxide (TiO2) into acacia gum/acrylic acid (AG/AAc). Nanocomposite hydrogels, bearing different functional groups, are constructed employing a gamma irradiation approach that would operate as adsorbents to remove strontium (Sr2+) and nickel (Ni2+) ions from their wastes. The structure of the prepared hydrogel and its nanocomposites were confirmed by FTIR, whereas the morphology was characterized by SEM. XRD and EDX analysis confirms that the TiO2 NPs are successfully encapsulated into the prepared hydrogel. The presence of TiO2 enhances the thermal stability of the prepared hydrogel. Adsorption extent is evaluated comprehensively concerning temperature, contact time, adsorbent dosage, metal ion concentration, and pH. The physical connection between the adsorbent surface and metal ions is strengthened once TiO2 NPs are included in a copolymeric matrix, which enhances adsorption. Pseudo-second-order kinetics accurately depict the adsorption process, and the Freundlich isotherm provides the most relevant explanation of the equilibrium data. There is a demonstration that sorption is a spontaneous, feasible, and endothermic chemisorption process by examining a variety of thermodynamic parameters, including ΔH, ΔG, and ΔS.

Experimental Investigation of the Optical Nonlinearity of Laser-Ablated Titanium Dioxide Nanoparticles Using Femtosecond Laser Light Pulses

In this report, the nonlinear optical (NLO) properties of titanium dioxide nanoparticles (TiO2 NPs) have been explored experimentally using femtosecond laser light along with the Z-scan approach. The synthesis of TiO2 NPs was carried out in distilled water through nanosecond second harmonic Nd:YAG laser ablation. Characterization of the TiO2 NPs colloids was conducted using UV-visible absorption spectroscopy, transmission electron microscopy (TEM), inductively coupled plasma (ICP), and energy-dispersive X-ray spectroscopy (EDX). The TEM analysis indicated that the size distribution and average particle size of the TiO2 NPs varied from 8.3 nm to 19.1 nm, depending on the laser ablation duration. The third-order NLO properties of the synthesized TiO2 NPs were examined at different excitation laser wavelengths and incident powers through both open- and closed-aperture Z-scan techniques, utilizing a laser pulse duration of 100 fs and a high repetition rate of 80 MHz. The nonlinear absorption (NLA) coefficient and nonlinear refractive (NLR) index of the TiO2 NPs colloidal solutions were found to be influenced by the incident power, excitation wavelength, average size, and concentration of TiO2 NPs. Maximum values of 4.93 × 10⁻⁹ cm/W for the NLA coefficient and 15.39 × 10⁻15 cm2/W for the NLR index were observed at an excitation wavelength of 800 nm, an incident power of 0.6 W, and an ablation time of 15 min. The optical limiting (OL) effects of the TiO2 NPs solution at different ablation times were investigated and revealed to be concentration and average size dependent. An increase in concentration results in a more limiting effect.

Pervaporation Membrane Development via PSf/PMMA/PDMS Polymeric Blends and ZSM-5/TiO2 Integration for Bioethanol Purification as Sustainable Green Energy

This study introduces a novel nanocomposite membrane designed for pervaporation (PV) by employing polymer blending, inorganic integration, and polymer coating techniques. ZSM-5 or TiO2 nanoparticles were synthesized and incorporated into a polysulfone (PSf) and poly(methyl methacrylate) (PMMA) matrix, followed by a coating of polydimethylsiloxane (PDMS) to enhance perm-selectivity. Comprehensive analyses confirmed the well-dispersed nature of the nanoparticles and a significant increase in hydrophilicity. The research systematically examined the effects of particle loading, PDMS coating, and temperature on the separation efficiency. The findings revealed that the PDMS-coated PSf/PMMA/ZSM-5 membrane with a 2 wt.% loading demonstrated a substantial 41% increase in permeate flux and achieved a separation factor of 61.227 ± 1.92 at 40 °C. These improvements are attributed to the establishment of water channels and the molecular sieving effect introduced by the ZSM-5 incorporation. This study suggests that the developed membrane offers promising enhancements for ethanol recovery through pervaporation, showcasing the potential of nanocomposite membranes in improving separation efficiency and selectivity.

Photoreversible Color-Switching Cu-Doped TiO2 Nanoparticles for High-Contrast Rewritable Printing.

Light-printable rewritable paper that can be used multiple times has attracted extensive attention because of its potential benefits in reducing environmental pollution and energy consumption. Developing rewritable paper with high black-to-colorless contrast, lasting legibility, and a fast response is fascinating but challenging. Here, we integrate the redox chemistry of Cu2+ ions into photoreductive TiO2 nanoparticles to produce Cu-doped TiO2 nanoparticles capable of highly photoreversible switching between colorless and black with excellent contrast and color stability. Incorporating such nanoparticles into hydroxyethyl cellulose produces a rewritable paper with the same appearance as that of conventional paper. More importantly, it demonstrates great features promising for practical applications, including high black-to-colorless contrast, fast light-printing (<20 s), long legible time (>3 days), high reversibility (>50 cycles), high resolution (90 μm), and large scale (A4 size) applicability.

Impact of nano-TiO2 on white Portland cement mortars: a combined XRD coupled rietveld, crystallographic and microstructural analysis

The present study investigated the structural, microstructural, and crystallographic changes associated with the addition of nano-TiO2 (NT) by intermixing and surface coating on freshly cast and hardened coatings on white Portland cement matrix samples at minimal dosages. Scanning electron microscopy (SEM) and VESTA were employed to analyze the microstructure morphology of the hydration products and the crystal structure parameters of the NT-modified white Portland cement mortar. Additionally, Rietveld refinement analysis was performed to quantify the crystal phases coupled with XRD using Xpert High Score Plus and Expo-2014 software. The Rietveld refinement analysis of the hardened coating surface followed by the fresh cast coating resulted in the most refined structural model compared with that of the intermixed and reference samples. The integration of NT also reduced the bond distances and polyhedral volumes, indicating denser atomic packing and enhanced interactions between the smaller NT particles and the white Portland cement matrix and enhancing the structural integrity within the matrix. Furthermore, SEM micrographs revealed a compact microstructure with enhanced CSH and reduced CH crystals in the NT-modified white cement mortar samples. The presence of hydration products and corresponding bonds were confirmed by Fourier Transform Infrared Spectroscopy.

Green synthesis of nitrogen-doped TiO2 nanoparticles with exposed {001} facets using Chromolaena odorata leaf extract for photodegradation of pollutants under visible light

Facet-tailored TiO2 nanoparticles (NPs) exhibit exceptional properties due to high surface energy. Conventional strategies for the fabrication of such TiO2 NPs involve harmful chemicals, which necessitates the development of environmentally benign pathways. Plant extract-assisted synthesis has emerged as a promising green alternative to conventional nanomaterial synthesis. This work introduces an innovative method for the synthesis of nitrogen-doped TiO2 (N-TiO2) NPs with exposed {001} facets using the leaf extract of a weed plant Chromolaena odorata, which is commonly known as Siam weed. The synthesis was carried out by sol-gel process with triethylamine (TEA), hydrazine hydrate and urea being the nitrogen precursors. The synthesised N-TiO2 NPs exhibited exposed {001} facets and showed a reduction in band gap. Photo-induced degradation of methylene blue dye was used to analyse the photocatalytic capability of N-TiO2 NPs in the visible range. The effect of N precursor, N dosage and light exposure time on the catalytic efficacy was studied. N-TiO2 NPs derived from TEA with 1 mol.% dopant achieved 98 % degradation in 180 minutes, while those synthesized with hydrazine and urea attained 96 % and 93 %, respectively when compared to 90 % degradation for undoped samples. The N-doping leads to significant advancement of photocatalytic effectiveness of the TiO2 NPs by introducing mid-gap levels in the forbidden energy gap that diminishes the charge carrier-recombination and boost the charge-carrier mobility of TiO2. This along with the existence of high energy facets causes a substantial advancement in the photocatalytic function in the visible region. The proposed method is a sustainable way for synthesising N-TiO2 NPs with exposed {001} facets for environment remediation applications.

SnO2-TiO2/reduced graphene oxide nanocomposites: Green synthesis and enhanced photocatalytic efficiency for dye removal

Titanium oxide nanoparticles (TiO2 NPs) have been interested in potential applications, including gas-sensing, energy storage, environmental remediation, and medical fields. In the present work, fabricated SnO2-TiO2/RGO nanocomposites (NCs) have been produced through a green precipitation approach. XRD, TEM, SEM, EDX, XPS, FTIR, UV, and PL analyses have been carefully applied to invistage the physicochemical properties of prepared NPs and NCs. The XRD data showed that the crystal structure of the TiO2 NPs was affected by the introduction of SnO2 NPs and RGO sheets. The spherical shape of the prepared samples and their morphologies were confirmed using TEM and SEM images. EDX and XPS analyses confirmed that tin (Sn), titanium (Ti), oxygen (O), and carbon (C) were further present in the SnO2-TiO2/RGO NCs. FT-IR spectra determines the functional groups with bands between the compositions of obtained NPs and NCs. Besides, the band gap energies of prepares samples were estimated from UV–vis spectra. It displayed that the absorption peak of the synthesized TiO2 NPs was improved after the addition of SnO2 NPs and an RGO sheet. PL analysis indicate that the PL intensity of the prepared TiO2 NPs was decreased with the addition of SnO2 NPs and RGO sheets due to a decrease in the recombination rate of electrons (e−)-holes (h+). As shown in photocatalytic results, the photodegradation of methylene blue (MB) dye of SnO2-TiO2/RGO NCs was reached 92.20% after 140 min of UV irradiation. These results suggest that the addition of RGO sheets occupied a role in enhanced the photocatalytic performance of the prepared NCs. This study highlighted that these samples could be applied in various applications such as photocatalytic and therapeutic areas.

Novel indicator film incorporating Dendrobium orchid extract and TiO2 nanoparticles for seafood freshness monitoring

This study aimed to develop a pH indicator film using a combination of hydrocolloids (polyvinyl alcohol, carboxymethyl cellulose, and rice flour; PCR film), Dendrobium orchid flower (DOF) extract, and TiO2 nanoparticles to monitor shrimp and crab freshness during 9 days of cold storage. LC-MS/MS analysis identified a rare anthocyanin, cyanidin-3-[6-sinapoyl-2-O-(2-(sinapoyl)glucosyl)-glucoside], in the DOF extract, responsible for its color expression. The DOF extract showed a clear color variation in different solutions (pH 1–13). TiO2 nanoparticles influenced the film's thickness, tensile strength (TS), elongation at break (EB), water vapor permeability (WVP), and color properties. Structural changes due to nanoparticles were confirmed via Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. PCR+DOF+8%TiO2 film showed the highest TS (13.75 ± 0.60 MPa), EB (2.24 ± 1.42 %), and WVP (3.57 ± 1.12 × 10-11 g·m·Pa-1·m-2·s-1) values and was more sensitive to ammonia vapor than acetic acid vapor. In practical applications, the film could effectively indicate shrimp spoilage through color change but was less precise for crab samples. The film effectively indicated shrimp spoilage through a color shift to green on the 4th day, correlating with total viable count and volatile nitrogen levels exceeding safe consumption thresholds. Thus, this film could serve as an efficient diagnostic tool for monitoring seafood spoilage.

Efficacy of Titanium Dioxide Nanoparticles Using Juniperus phoenicea in Controlling Rice Weevil (Sitophilus oryzae) and Its Effect on the Microbial Contents and Nutritive Value of Grains

The rice weevil, Sitophilus oryzae is a primary pest attack many kinds of crops. It causes a lot of loss and reduces the economic values of products. The study investigated to determine the insecticidal effect of titanium dioxide nanoparticles using Juniperus phoenicea (TiO2 NPs) against the insect, and the nutritional and antimicrobial value of rice grains after treatment by TiO2 NPs was estimated. Adult was the target of bioassay of the biocomponent. Four concentrations were prepared as 30, 50, 80 and 100%. Some biochemical components were evaluated as response indicators of insect. Obtained data demonstrated significant differences between the four concentrations, where the highest mortality was recorded after 120 h. On the adults (85%). Treatment with the titanium dioxide nanoparticles inhibited the activities of acetylcholine esterase and total soluble protein. While it increases the activity of catalase as antioxidant enzyme. Nutritional values increased with increasing the proportion of TiO2 NPs, except for the decrease in protein. No colonization of coliform bacteria and fungi cell was recorded in 80% of TiO2 NPs, aerobic bacteria were reduced to a lower number 12 CFU/g 103 at 100%. Biosynthesized titanium dioxide nanoparticles with J. phoenicea extract is promising bio-insecticide and antimicrobial in integrated pest management control, preserving the nutritional value of grains during storage.

Assessment of trade-off, exergetic performance, and greenhouse gas impact-cost analysis of a diesel engine running with different proportions of TiO2, Ag2O, and CeO2 nanoadditives

In this study, the effects of adding different proportions of TiO2, Ag2O, and CeO2 nanoparticles to a three-cylinder, water-cooled, four-stroke, direct injection diesel engine on engine performance and exhaust emissions are experimentally investigated. The experiments are conducted at four different engine loads (10, 20, 30, and 40 Nm) and a constant engine speed (1800 rpm). TiO2, Ag2O, and CeO2 nanoparticles are added to the diesel fuel at concentrations of 50 and 75 ppm each. The test fuels used in the study are as follows: D100, DTi50, DTi75, DAg50, DAg75, DCe50 and DCe75. Using the experimental results, analyses of energy, exergy, sustainability, greenhouse gas (GHG) emission impact, and cost are performed. The experimental results reveal that the use of nanoparticles in diesel fuel reduces BSFC. The highest reduction in BSFC is achieved with DTi75 fuel, averaging 9%. Additionally, DTi75 fuel shows an average increase of 19% in NOx emissions compared to D100 fuel, while smoke emissions decrease by an average of 30%. The highest average increase in exergy efficiency compared to D100 fuel is obtained with DAg50 fuel (5.6%), followed by DTi75 fuel (5.3%). The addition of nanoparticles to diesel fuel also leads to an increase in GHG emissions. Compared to D100 fuel, the highest average contribution to GHG emissions increase is shown by DTi75 fuel (12%), while the lowest average contribution is observed with DAg50 fuel (4%).

Quasi-solid-state monolithic DSSCs with optimized spacer layers and composite electrolytes for better efficiency and stability

In this study, high-performance quasi-solid-state monolithic dye-sensitized solar cells (QS-M-DSSCs) were designed using an optimized spacer layer architecture to enhance electrolyte transport and improve cell performance. Spacer layers, made from a combination of zirconium oxide (ZrO2) and titanium dioxide (TiO2), were precisely tuned to reduce mass-transport limitations. A 5.2 μm thick ZrO2/TiO2 layer provided good light reflectance and incident photon-to-current conversion efficiency compared to double layers of either material alone. Electrochemical impedance spectroscopy analysis of the m-DSSCs revealed that this architecture (photoelectrode TiO2 layer/ZrO2/TiO2 spacer layer/counter electrode catalyst layer) significantly increased recombination resistance, leading to an improvement in open-circuit voltage. As a result, acetonitrile iodide liquid-DSSCs using N719 dye achieved a high power conversion efficiency (PCE) of 8.45 %, surpassing cells with alternative spacer designs. For fully printable QS-M-DSSCs, printable gel electrolytes (PGEs) composed of polyethylene oxide and polymethyl methacrylate in 3-methoxypropionitrile (MPN) were employed. A 5 wt% PEO/PMMA composition demonstrated fast and efficient penetration of the PGEs through spacer layers. Moreover, incorporation of 4 wt% TiO2 nanoparticles into PGEs further enhanced their electrochemical properties, achieving a PCE (7.31 %) higher than cells with liquid electrolytes (6.72 %). QS-M-DSSCs demonstrated greater stability than liquid-state DSSCs.

Numerical investigation of heat transfer and pressure drop of water-nanofluid flow in a three-dimensional wavy mini-tube

This research employs three-dimensional simulations to investigate the behavior of pure water and nanofluids consisting of Al2O3 and TiO2 particles within a sinusoidal mini-tube as a single-phase suspension. The impact of a mini-tube's sinusoidal amplitude and wavelength on laminar flow properties is investigated in Reynolds numbers ranging from 100 to 600. The results present that performance evaluation criterion of mini-tube is more proper in the amplitude of 3 mm and wave length of 16 mm. Performance evaluation criterion of sinusoidal shaped mini-tube with pure water in comparison with straight mini-tube, shows that sinusoidal mini-tube has the proper performance which the performance evaluation criterion is greater than 1. Proper selected mini-tube is also used with nanofluids. In this simulation, proposed nanofluids are water-Al2O3 and water-TiO2 nanofluids with volume fractions of 2% and 4%. The results of this investigation reveal that using nanofluids improves performance evaluation criterion. Also, comparison of two different nanoparticles shows that Al2O3 nanoparticles have better performance in comparison with TiO2 nanoparticles. By changing geometrical parameters as amplitude and wave length and finding proper mini-tube, it is seen that performance evaluation criterion is increased two times in comparison with straight tube. Also, using nanofluid in proper mini-tube in comparison with pure water in the same mini-tube, leads to improvement of cooling and thermal performance up to of 20%, in the different Reynolds numbers.

Facile electrospinning-electrospray method to fabricate flexible rice straw-derived cellulose acetate/TiO2 nanofibrous membrane with excellent photocatalytic performance

A novel and facile electrospinning-electrospray (EE) method that based on electrospinning technique and simultaneous electrospray was proposed to anchor TiO2 (P25) nanoparticles on the surface of rice straw-derived cellulose acetate (CA) nanofiber, a series of EE-CA/P25 nanofibrous membranes with different P25 dosage were successfully fabricated, which were characterized in terms of SEM, TEM, FI-IR, XRD, DRS, PL, UV–vis and 3D-EMMs, etc. Results confirmed that P25 nanoparticles were anchored on the surface of CA nanofiber. For different organic dyes of Methylene blue (MB), Rhodamine B (RhB) and Methyl orange (MO), EE-CA/P25(0.05) nanofibrous membrane toward MB dye showed the best photocatalytic degradation efficiency of 99.13 % after 30 min of light exposure. For the different antibiotics of Tetracycline (TC), Ciprofloxacin (CIP) and Sulfamethoxazole (SMX), EE-CA/P25(0.05) exhibited the best photocatalytic degradation efficiency of 83.59 % for TC after 30 min of light exposure. Moreover, EE-CA/P25(0.05) exhibited a good antimicrobial efficiency of 98.42 % for E. coli, and maintained 97.49 % after 5 cycles. The reactive radical trapping experiments revealed that h+, •O2−, and •OH participated in the reaction, and h+ and •O2− played a major role in the photocatalytic degradation process. Moreover, EE-CA/P25(0.05) flexible membrane was easy to recycle and transform rice straw waste into treasure.

Photoactivated rose bengal-doped TiO2 nanoparticles modified fifth-generation adhesive on the survival rate of Streptococcus mutants and mechanical properties of tooth-colored restorative material to carious dentin.

Assessment of the antimicrobial, micro tensile bond strength (μTBS), and degree of conversion (DC) of fifth-generation adhesive modified using photoactivated 0.5% rose bengal (RB) and photoactivated RB-doped titanium dioxide nanoparticles (TiO2NPs) in different concentrations (2% and 5%) as compared with the unmodified adhesive bonded to the carious affected dentin (CAD). Forty mandibular molars with caries progression up to the middle third of the dentin, as per the International Caries Detection and Assessment System (ICDAS) score of 4 and 5 were included. Specimens were divided into four groups based on etch and rinse adhesive (ERA) modification group 1: unmodified ERA, group 2: photoactivated 0.5% RB photosensitizer (PS) modified ERA, group 3: photoactivated RB-doped 2 wt% TiO2NPs adhesive, group 4: photoactivated RB-doped 5 wt% TiO2NPs adhesive. Followed by adhesive and composite restoration on the CAD surface. All the specimens were thermocycled and an assessment of μTBS and failure pattern analysis was performed. The antibacterial potency of RB and RB-doped TiO2NPs (2% and 5%) followed by their activation using visible light against Streptococcus mutans (S.mutans) were tested. The survival rate of S.mutans was assessed using the Kruskal-Wallis test. The analysis of μTBS involved the use of ANOVA, followed by a post-hoc Tukey honestly significant difference (HSD) multiple comparisons test. Group 1 (Unmodified ERA) (0.52 ± 0.31 CFU/mL) treated samples unveiled the highest means of bacterial survival and lowest μTBS (11.32 ± 0.63 MPa). Nevertheless, group 4: photoactivated RB-doped 5 wt% TiO2NPs adhesive displayed the lowest outcomes of S.mutans survival (0.11 ± 0.02 CFU/mL) and highest bond strength (18.76 ± 1.45 MPa). The photoactivated RB-doped 2 wt% TiO2NPs in adhesive demonstrated promising enhancements in both μTBS and antibacterial efficacy against S.mutans. However, it is noteworthy that this modification led to a decrease in the DC of the adhesive. RESEARCH HIGHLIGHTS: Unmodified ERA-treated samples unveiled the highest bacterial survival and the lowest μTBS. Photoactivated RB-doped 5 wt% TiO2NPs adhesive displayed the lowest S.mutans survival rate and highest bond strength. DC decreased with an increase in concentration of TiO2.

TiO2 intercalated MWCNTs nanocomposite sensor for the detection and quantification of 5-Fluorouracil

The present analysis deals with the fabrication of novel electrochemical sensing platforms for the determination of the anti-cancer drug 5-Fluorouracil (5-FLU). Multiwalled carbon nanotubes/titanium dioxide nanoparticles (TiO2·MWCNTs) modified carbon paste electrodes were constructed and used to quantify 5-FLU in pH 7.0. TiO2·MWCNTs nanocomposite reveals a non-uniform distribution of agglomerated TiO2 nanoparticles over the smooth surface of MWCNTs At the TiO2∙MWCNTs/CPE, the 5-FLU molecule underwent an irreversible electro-oxidation process. The proposed electrode platform exhibited a high catalytic effect for the 5-FLU. The TiO2∙MWCNTs/CPE sensor shows the detection limits of 2.7nM for 5-FLU with sensitivity of 82.15µA·µM−1·cm−2. The sensor was employed to detect the desired drug moiety in the urine samples of pharmaceutical drugs along with spiked water and soil samples; the good recovery values demonstrating the applicability and selectivity of the sensor were supported by excipient interference investigation. Thus, the developed sensors and method makes them a promising alternative for future research to determine other bio-active molecules in pharmaceutical and clinical samples.

Multifunctional nanocomposites based on kaolinite/titania/iron applied to hydrogen peroxide production and bisphenol–A removal

The rising global demand for hydrogen peroxide, recognized for its eco–friendly properties, underscores the need for greener synthesis methods. Traditional production processes pose environmental risks, while direct synthesis faces challenges like water formation, explosion hazards, and stability issues, limiting industrial application. On the other hand, Bisphenol A (BPA), an endocrine disruptor widely used in plastics, presents significant environmental and health concerns due to its potential leaching into food and water. The present work introduces efficient and selective photocatalysts aimed at sustainable hydrogen peroxide synthesis and BPA degradation. Both processes were enhanced by the synergistic properties of Fe2O3–TiO2 nanoparticles dispersed within a kaolinite matrix. The Fe2O3–TiO2 photocatalysts, characterized by photoluminescence spectroscopy and X–ray diffraction, showed reduced emission upon iron incorporation and anatase presence on the kaolinite surface. The photocatalytic activity was evaluated through hydroxylation of terephthalic acid, revealing a 127 μmol/L min hydroxylation rate for the KaFeTi400 sample. BPA degradation studies indicated optimal performance in acidic conditions, achieving 96 % removal in 2 h and 98 % in 4 h, with the addition of H2O2 enhancing efficiency. Further, the photocatalyst facilitated benzyl alcohol oxidation to benzaldehyde, demonstrating a H2O2 production rate of 120 μmol. These findings highlight the multifunctional capabilities and environmental benefits of the photocatalyst, underscoring its potential for sustainable hydrogen peroxide synthesis and broader applications in environmental remediation. The catalysts address the pressing challenges associated with hydrogen peroxide synthesis and pollutant removal, particularly in the context of sustainability and environmental impact.

Green and chemical synthesis of TiO2 nanoparticles: An In-depth comparative analysis and photoluminescence study

Titania nanoparticles were synthesized by sol-gel method using chemical and natural solvents. Isopropanol is used as a chemical solvent for the reduction of ions. Further, Jasminum and Magnolia champaca flower extracts were individually used as natural solvents which acts as both reducing and stabilizing agents. The role of natural solvents over chemical solvents on the structure, phase, morphology, and optical properties of TiO2 nanoparticles were investigated. Synthesis using natural solvents led to rutile phase of TiO2 nanoparticles while, chemical synthesis produced anatase phase. Green synthesis yielded larger crystallite size TiO2 compared to chemical synthesis. Synthesized TiO2 exhibited PL emission centered at 397 nm with excitation 325 nm associated with weak emissions noticed at 450 nm, 470 nm, and 520 nm.

Green synthesis and anticancer activity of titanium dioxide nanoparticles using the endophytic fungus Aspergillus sp.

Titanium dioxide nanoparticles (TiO2 NPs) have attracted significant attention for their unique physicochemical features and various applications. This study demonstrated the biosynthesis of TiO2 NPs using Aspergillus fungal extract that served as a green and eco-friendly reducing and stabilizing agent. The biosynthesized nanoparticles were analyzed using SEM and TEM to determine their morphology, size, and distribution, FTIR to determine functional groups, and Zeta potential to assess their surface charge and stability. An extensive review of the Protein Data Bank (PDB) and literature indicated that TiO2 could target various cancer-relevant matrix metalloproteinases. In vitro screening indicated promising anticancer effects against the MCF7 breast cancer cell line. To investigate the possible mode of action of TiO2 NPs as an anticancer agent, human matrix metalloproteinase-3 was highlighted as a protein inhibited by metallic ions like PtCl2. Therefore, we investigated whether TiO2 could similarly interact with the active site of MMP-3. We hypothesized that TiO2 could interact with the MMP-3 active site and replace PtCl2 with modelled TiO2 in its co-crystallized binding site. A 100 ns-long MDS, binding free energy (ΔGBinding) of PtCl2 and TiO2 within MMP-3 binding site indicated that TiO2's enhanced binding affinity and stability, as evidenced by a ΔGBinding of −7.23 kcal/mol and average RMSD of 0.89 Å, compared to PtCl2's lower affinity. In conclusion, endophytic fungi can be used efficiently in the biosynthesis of nanoparticles. Our study indicated TiO2 NPs have a potential anticancer effect, suggesting TiO2 binds to MMP3, potentially offering comparable inhibitory effects on the enzyme's activity.

Surface Cladding of Mild Steel Coated with Ni Containing TiO2 Nanoparticles Using a High-Temperature Arc from TIG Welding

This study explores the use of a high-temperature arc generated during tungsten inert gas (TIG) welding to enhance the mechanical properties of the surface of AISI 1020 steel. An innovative two-step process involves using the high-temperature arc as an energy source to fuse a previously electrodeposited Ni/TiO2 coating to the surface of the substrate. The cladded surface is characterised by a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), an optical microscope (O.M.) equipped with laser-induced breakdown spectroscopy (LIBS), Vicker’s microhardness testing, and pin-on-plate wear testing. The treated surface exhibits a unique amalgamation of hardening mechanisms, including nanoparticle dispersion strengthening, grain size reduction, and solid solution strengthening. The thickness of the electrodeposited layer appears to strongly influence the hardness variation across the width of the treated layer. The hardness of the treated layer when the Ni coating contains 30 nm TiO2 particles was found to be 451 VHN, validating an impressive 2.7-fold increase in material hardness compared to the untreated substrate (165 VHN). Similarly, the treated surface exhibits a twofold improvement in wear resistance (9.0 × 102 µm3/s), making it substantially more durable in abrasive environments than the untreated surface. Microstructural and EDS analysis reveal a significant reduction in grain size and the presence of high concentrations of Ni and TiO2 within the treated region, providing clear evidence for the activation of several strengthening mechanisms.