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Structural, optical and photoluminescence studies of sol-gel synthesized pure and iron doped TiO2 photocatalysts
摘要： Pure and Iron doped TiO2 nanoparticles were synthesized using the sol-gel method. These materials were characterized by X-ray diffractometer (XRD), high-resolution transmission electron microscope (HR-TEM), scanning electron microscope (SEM), Energy dispersive X-ray (EDX), UV-Vis diffuse reflectance spectroscopy (DRS), Fourier-transform infrared (FTIR), Raman and fluorescence spectrometer. XRD analysis revealed that all the samples were a single phase with anatase nanocrystallite structures. The crystallite size of titania reduced from 9.64 nm to 7 nm with Fe doping. The HRTEM images of the TiO2 and 3% Fe doped TiO2 have revealed that all the particles have a spherical shape with an average particle size of 10 nm and 8 nm respectively. The characteristic peak at 482 cm-1 of the Ti–O bond stretching vibrations can be evidently observed from FTIR analysis. The Raman blue shift was found in the Fe doped TiO2 samples. Fe-doped TiO2 nanoparticles showed a significant red-shift in band edge as compared with pure TiO2 nanoparticles. The redshift of band gap was detected in Fe doped TiO2 nanoparticles. The photoluminescence (PL) emission intensity of Fe doped TiO2 nanoparticles decreases with an increase in Fe doping concentration. The photocatalytic efficiencies of the Fe-doped TiO2 nanoparticles have shown a strong photocatalytic activity (PCA) response. At constant irradiation time, the Fe-doped titania nanoparticles display more catalytic activity compared to undoped TiO2. The photodegradation efficiencies typically decline with an increase in the concentration of Fe+3 doping for the decolorization of methylene blue (MB) under visible light irradiation.
关键词： band gap,Raman modes,photocatalytic activity,TiO2 nanoparticles,methylene blue,PL emission
更新于2025-11-21 11:18:25
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The coherence between TiO2 nanoparticles and microfibrillated cellulose in thin film for enhanced dispersal and photodegradation of dye
摘要： Microfibrillated cellulose (MFC) was used to enhance the dispersal and photocatalytic properties of TiO2 nanoparticles. With the small amount of MFC (0.1 wt.% or 0.3 wt.%), TEM images showed that particle agglomeration was greatly minimized due to the coherence between TiO2 nanoparticles and MFC. The surface area and pore volume of TiO2 nanoparticles was enhanced as proven in N2 adsorption-desorption analysis. Thermogravimetric and Fourier transform infrared spectra further confirmed the presence of MFC in TiO2/MFC coating solution. Using commercial adhesive, TiO2 and TiO2/MFC were spray coated on polyvinyl chloride sheet. The photocatalytic thin films were examined using scanning electron microscope with Energy dispersive X-ray analysis. The presence of MFC was not only helpful to enhance particle dispersal but also supportive to increase the hydrophilicity of the thin film. In comparison to TiO2 coating, the films were capable to adsorb 50% more methylene blue in 90 min. TiO2/MFC coatings removed 90% of methylene blue dye in 90 min under UV irradiation.
关键词： Spray coating,Photocatalysis,Dye,TiO2 nanoparticles,Microfibrillated cellulose,Adsorption
更新于2025-11-19 16:56:35
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Carboxylic acid-functionalized TiO <sub/>2</sub> nanoparticle-loaded PMMA/PEEK copolymer matrix as a dental resin for 3D complete denture manufacturing by stereolitographic technique
摘要： The main goal of the present investigation was to the synthesis of bioactive TiO2 nanoparticle-incorporated poly(methylmethacrylate)/polyetheretherketone nanocomposite for enhanced antibacterial and biocompatibility characteristics with suitable properties for manufacturing 3D printed stereolitographic dental prosthesis. The carboxylic acid-functionalized TiO2 nanoparticles have been dispersed into the copolymer matrixes through emulsion polymerization method, and the structural and morphological properties were investigated by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy, and energy dispersive X-ray (EDX) analytical techniques. The FTIR spectrum of synthesized nanocomposites that shows high intense peaks at 2,970–2,850 cm?1 is related to the symmetric and asymmetric stretching C-H vibration of methyl and methylene groups of the polymer matrix. The microscopic results of nanocomposite exhibited that functionalized nanoparticles were effectively and uniformly dispersed into the polymer matrix in the absence of particle agglomerations, and it has been given excellent killing efficiency of 99% under dark conditions against bacterial pathogens Escherichia coli and Staphylococcus aureus and also exhibited favorable cell compatibility with dental pulp cells. This facile synthesized nanocomposite was efficaciously employed for denture manufacturing with stereolitographic technique.
关键词： Stereolitographic method,TiO2 nanoparticles,Antibacterial,Dental,Copolymer
更新于2025-09-23 15:23:52
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Photo-refreshable electrochemical sensor based on composite electrode of carbon nanotubes and TiO2 nanoparticles
摘要： Surface fouling and passivation on the electrode during electrochemical process is a major challenge for the practical applications of electrochemical sensors. Herein, a photo-refreshable electrochemical sensor was presented based on carbon nanotubes/TiO2 nanoparticles (CNTs/TiO2-NPs) composite electrode, which not only exhibits high electrochemical activity towards the determination of 5-hydroxytryptamine and dopamine, but also displays excellent reproducibility in the surface electrochemical monitoring without damaging microstructure. The linear range for 5-hydroxytryptamine determination is 0.5-400 μM (R=0.991) under UV light irradiation with a detection limit of 0.47 μM (S/N=3). The CNTs/TiO2-NPs electrode also shows excellent response to dopamine, with the linear range of 0.05 μM to 100 μM and a detection limit of 0.022 μM (S/N =3). The high performance of this photo-refreshable electrochemical sensor should be attributed to the excellent photocatalytic activity of the TiO2-NPs and the high electrochemical activity of CNTs.
关键词： carbon nanotubes,photocatalysis,TiO2 nanoparticles,electrochemical sensors,surface fouling
更新于2025-09-23 15:22:29
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Preparation and Characterization of Polymer Composite Materials Based on PLA/TiO2 for Antibacterial Packaging
摘要： Polymer composite materials based on polylactic acid (PLA) filled with titanium dioxide (TiO2) nanoparticles were prepared. The aim of this work was to investigate the antibacterial action of TiO2 against a strain of E. coli (DH5α) to obtain information on their potential uses in food and agro-alimentary industry. PLA/TiO2 systems were prepared by a two-step process: Solvent casting followed by a hot-pressing step. Characterization was done as a function of particle size (21 nm and <100 nm) and particle content (0%, 1%, 5%, 10%, and 20%, wt %). Structural characterization carried out by X-ray diffraction (XRD) and Fourier Transformed Infrared spectroscopy (FTIR) did not reveal significant changes in polymer structure due to the presence of TiO2 nanoparticles. Thermal characterization indicated that thermal transitions, measured by differential scanning calorimetry (DSC), did not vary, irrespective of size or content, whereas thermogravimetric analysis (TGA) revealed a slight increase in the temperature of degradation with particle content. Bacterial growth and biofilm formation on the surface of the composites against DH5α Escherichia coli was studied. Results suggested that the presence of TiO2 nanoparticles decreases the amount of extracellular polymeric substance (EPS) and limits bacterial growth. The inhibition distances estimated with the Kirby-Bauer were doubled when 1% TiO2 nanoparticles were introduced in PLA, though no significant differences were obtained for higher contents in TiO2 NPs.
关键词： antibacterial packaging,polylactic acid (PLA),polymer nanocomposites,TiO2 nanoparticles
更新于2025-09-23 15:22:29
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A Phosphonate Substituted Ruthenium(II) Bipyridyl Derivative as Photoelectrochemical Probe for Sensitive and Selective Detection of Mercury(II) in Biofluids
摘要： A ruthenium(II) bipyridyl derivative photoelectrochemical probe, Ru-1, is synthesized and coupled with TiO2 nanoparticles (Ru-1/TiO2) for the specific recognition and highly sensitive PEC detection of Hg2+ in a series of biofluids. The probe is designed with a chromophore, a thiocyanate recognition unit, a π-conjugated photoelectron transfer pathway, and a phosphonate anchor. TiO2 nanoparticles with strong affinity to phosphonate and suitable conduction band energy are used as intermediate layers to increase the Ru-1 adsorption amount and amplify the photocurrent response. Under irradiation, the Ru-1/TiO2/FTO with strong visible light harvesting capacity, aqueous stability and efficient photoelectron transfer, shows a high and stable photocurrent response. In the presence of Hg2+, however, the specific Hg2+ and NCS coordination changes the photophysical properties of Ru-1, imposing the probe with a wider band gap, a weaker absorbance, and a poorer photoelectron and hole separation efficiency, thus resulting in a significant photocurrent decrease. Based on the Hg2+ induced photocurrent change, the Ru-1/TiO2/FTO shows good selectivity and high sensitivity towards the PEC detection of Hg2+, with wide linear ranges from 10-12 to 10-7 and 10-7 to 10-3 g/mL, and a low limit of detection of 0.63 pg/mL. The PEC probe is recyclable and accurate for selective detection of Hg2+ in urine, serum and cell extracts. The whole analysis can be completed within 15 minutes. These good analytical performances indicate the PEC method might have great potential for the onsite detection of small molecules in bio-systems.
关键词： Hg2+ detection,photoelectrochemical probe,TiO2 nanoparticles,ruthenium(II) bipyridyl derivative,biofluids
更新于2025-09-23 15:21:21
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Molecular Insights into NO-Promoted Sulfate Formation on Model TiO <sub/>2</sub> Nanoparticles with Different Exposed Facets
摘要： In this study, molecular insights into NO-promoted SO2 oxidation on model TiO2 with well-defined (001), (010) and (101) facets are investigated in laboratory. The adsorbed SO2 is significantly promoted to transform into sulfate by the coexisting NO on the three facets. The appearance of active oxygen species indicates an active oxygen species-initiated NO oxidation. The resulting NO2 acts as an oxidant to convert adsorbed sulfite on hydroxyls to sulfate species. The (101) facet presents the best performance in the NO-promoted sulfate formation possibly owing to its desirable structure to accommodate SO3 2-, NO2 and molecular water. The uptake coefficient (γt) of SO2 increases by the coexistence of NO on (001) facet at 0% RH, and is relative humidity (RH) dependent, which first decreases from 0% RH to 32% RH but then increases in the range of 32% - 80% RH. The probable explanation is the combined contribution of the blocking effect of water and the hydration of SO2. The finding in this study provide an insight into the possibility of its occurrence on common mineral dusts and requires further investigation.
关键词： NO-promoted sulfate formation,sulfate aerosol,heterogeneous reaction,mineral dust,TiO2 nanoparticles
更新于2025-09-23 15:21:01
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Application of Colloidal Precipitation Method Using Sodium Polymethacrylate as Dispersant for TiO <sub/>2</sub> /PVDF Membrane Preparation and Its Antifouling Properties
摘要： Immobilized titanium dioxide (TiO2) nanoparticles on flat sheet polymeric membranes have been found effective for fouling reduction in recent researches. The main challenge in this field is to obtain ultrafine and stable nanodispersions. In this study, composite polyvinylidene fluoride/TiO2 (PVDF/TiO2) ultrafiltration membranes were prepared via phase inversion and colloidal precipitation method. Stable TiO2 suspensions were prepared using sodium polymethacrylate as dispersant and sonication without altering of the coagulation bath pH. The effect of different concentrations of TiO2 nanoparticles in the coagulation bath was also investigated. The membrane morphology (distribution of nanoparticles on the membrane surface) was observed by scanning electron and atomic force microscopy. Properties of the neat and the composite membranes were also characterized using energy dispersive X-ray spectroscopy and contact angle and membrane porosity measurements. The neat and the composite membranes were further investigated in terms of bovine serum albumin rejection and flux decline in cross flow filtration experiments. The results showed that the PVDF/TiO2 composite membrane using dimethylacetamide/triethyl phosphate as solvent and 0.05 g/L of TiO2 in the coagulation bath exhibits improved antifouling properties.
关键词： TiO2 nanoparticles,antifouling properties,ultrafiltration,colloidal precipitation,PVDF membrane
更新于2025-09-23 15:21:01
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Tuning the Optical Band Gap of Pure TiO2 via Photon Induced Method
摘要： Titanium dioxide, a well known photocatalyst will become more useful if it utilizes visible light. Many efforts have been made to achieve the utilization of visible light by TiO2 for photocatalytic activity by changing the preparation methods or by doping various transition metals. Herein, a novel Photon Induced Method (PIM) is being proposed to produce oxygen-rich TiO2 with modified optical band gap and high stability. The prepared TiO2 nanoparticles have been subjected to various characterizations such as XRD, HRSEM, HRTEM, FTIR, UV-Vis and PL. XRD results reveal that as the calcination temperature is increased, the crystallite size of the TiO2 nanoparticles is seen to increase. Also, the XRD results reveal an increase in pure anatase phase stability upto 750°C when compared to earlier reports of pure anatase phase stability upto 650°C. HRTEM analysis shows the formation of nanosized bullet like structure. A narrowing of optical band gap to 3.09 eV is evident through UV-Vis absorption studies. This tuning of band gap is expected to facilitate the absorption of visible light. The photocatalytic activity of the prepared TiO2 nanoparticles has also been studied. The results reveal that TiO2 nanoparticles prepared by this novel method exhibit an increased photocatalytic activity when compared to the standard Degussa P25 sample reported earlier.
关键词： Pure TiO2 nanoparticles,Optical bandgap,Photocatalytic activity,Visible light
更新于2025-09-23 15:21:01
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On the Role of Plasmonic Nanoparticles on the Photocatalytic of TiO <sub/>2</sub> Nanoparticles for Visible-Light Photoreduction of Bicarbonate
摘要： The potential application of anatase titanium dioxide (TiO2) nanoparticles for solar fuel generation has been recently attracting many attentions due to its excellent chemical stability. Nevertheless, the fast charge recombination during photoexcitation process may often reduce the photocatalytic activity. This work presents the role of plasmonic Au nanoparticles on enhancing the photocatalytic activity of TiO2 nanoparticles for a visible-light-driven conversion of bicarbonate to formate. Here, two types of nano-sized Au and TiO2 heterostructures, i.e., Au-TiO2 Janus nanostructures and core-shell Au@TiO2 nanostructures were successfully prepared and characterized using UV-Vis and HR-TEM. Results demonstrated that Au-TiO2 Janus nanostructures had a superior photocatalytic activity compared to TiO2 nanoparticles and core-shell Au@TiO2 nanostructures. This photocatalytic enhancement is believed due to the presence of surface plasmon resonance (SPR) phenomenon in Au nanoparticles that provides a Fermi energy level, which could prevent the charge recombination process during photoexcitation.
关键词： Visible-Light Photoreduction,Bicarbonate,Plasmonic Nanoparticles,Photocatalytic,TiO2 Nanoparticles
更新于2025-09-23 15:19:57