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- 2019
- Dye-sensitized solar cell
- Photoelectrode
- Light scattering layer
- Transmittance
- White pigment (R902+)
- Rutile titanium dioxide
- Optoelectronic Information Materials and Devices
- Tribhuvan University
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Photoactive Gel for Assisted Cleaning during Olive Mill Wastewater Membrane Microfiltration
摘要: A photoactive gel has been fabricated on the surface of polyethylene membranes for enhancing the fouling resistance during olive mill wastewater treatment. Light and pH responsive materials have been introduced in the membrane surface through the build up of a layer-by-layer pattern, which is formed by photocatalytic nanoparticles and ionic polyelectrolytes. The best working conditions to contrast foulants adsorption have been explored and identified. Repulsive interfacial forces and assisted transfer of foulants to catalytic sites have been envisaged as crucial factors for contrasting the decline of the flux during microfiltration. Tests in submerged configuration have been implemented for six continuous hours under irradiation at two different pH conditions. As a result, a worthy efficiency of the photoactive gel has been reached when suitable chemical microenvironments have been generated along the shell side of the membranes. No additional chemical reagents or expensive back-flushing procedures have been necessary to further clean the membranes; rather, fast and reversible pH switches have been enough to remove residues, thereby preserving the integrity of the layer-by-layer (LBL) complex onto the membrane surface.
关键词: submerged microfiltration,layer-by-layer,titanium oxide nanoparticles,water treatment,self-cleaning
更新于2025-09-23 15:23:52
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Application of Titanium Dioxide Self-Cleaning Coatings on Photovoltaic Modules for Soiling Related Losses Reduction
摘要: Several studies have assessed the influence of soiling deposition on Photovoltaic (PV) modules front-cover with regards to performance losses over time. In fact, soiling phenomena in PV systems are ascribed as responsible for medium and long-term yield reduction up to 16% over the first-year of outdoor exposure. Provided that PV technology is a low yield energy production source, maintaining module initial power output declared values is of the outmost importance to ensure that the return time of investment matches project calculations. The scope of this work was a detailed investigation on self-cleaning coating application as a viable retrofit option on already installed modules, or on newly built PV systems, to avoid soiling build-up on front-covers and guarantee threshold performance level in time. The aim is to provide system designers with a consistent alternative to manual cleaning, without losing effectiveness in terms of yield maintenance. The use of self-cleaning coating instead of acting on panels on a regular basis is more convenient in terms of operation and cost. These issues were analyzed through a set of experiments performed both on commercial size modules and laboratory assembled samples. Results prove product compatibility with PV components and its effectiveness in preventing soiling and dust deposition. Outcomes are presented in terms of maximum power output (Pmax) variation according to measurements performed in Standard Test Conditions (STC) at different time steps. In addition, a parallel comparison with uncoated modules exposed to the same outdoor conditions is also proposed to allow for Pmax variation monitoring performed on a reference sample.
关键词: Titanium Dioxide,PV Maintenance,Soiling,Yield Losses,Self-Cleaning
更新于2025-09-23 15:23:52
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Ultraviolet treatment restores bioactivity of titanium mesh plate degraded by contact with medical gloves
摘要: Titanium mesh plate (Ti mesh) used for bone augmentation inadvertently comes into contact with medical gloves during trimming and bending. We tested the hypotheses that glove contact degrades the biological capability of Ti mesh and that ultraviolet treatment (UV) can restore this capability. Three groups of Ti mesh specimens were prepared: as-received (AR), after glove contact (GC), and after glove contact followed by UV treatment. The AR and GC meshes were hydrophobic, but GC mesh was more hydrophobic. AR and GC meshes had significant amounts of surface carbon, and Si content was higher for GC mesh than for AR mesh. UV mesh was hydrophilic, and carbon and silicon content values were significantly lower in this group than in the AR and GC groups. The number, alkaline phosphatase activity, and mineralization ability of attached osteoblasts were significantly lower in the GC group than in the AR group and markedly higher in the UV group than in the AR group. In conclusion, glove contact caused chemical contamination of Ti mesh, which significantly reduced its bioactivity. UV treatment restored bioactivity in contaminated Ti mesh, which outperformed even the baseline Ti mesh.
关键词: photofunctionalization,osteoblasts,titanium mesh,guided bone generation
更新于2025-09-23 15:23:52
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Harnessing designer biotemplates for biomineralization of TiO2 with tunable photocatalytic activity
摘要: Biomineralization is a promising material synthesis strategy for environmentally benign production of nanostructured metal oxides. An important question is whether biomineralization can be used in the biomimetic synthesis of TiO2 with tunable photocatalytic properties that are conducive to diverse solar energy conversion applications. Here, we report the biomineralization of energy-state-modified TiO2 nanoparticles, where the critical properties closely related to their photocatalytic activity can be manipulated by tailoring the nature of the designer biotemplates. For this purpose, STB1 heptapeptide was employed as a nucleation center to induce TiO2 biomineralization. Three distinctive types of biomolecules (peptide, protein, and phage) were deliberately designed to contain the STB1 nucleation core at different local densities and intermolecular distances. The degree of substitutional nitrogen-doping and the morphology are all subject to the context-dependent differential availability of STB1 in the biomineralization milieu. Phage-induced biomineralization results in TiO2 with modified energy state and wire-like network morphology, which account for significantly enhanced charge dissociation/transport performance and high photocatalytic activity. This is the first study to report that a specific peptide with biomineralizing activity exerts differential impacts on the properties of resulting biomineralization products in a context-dependent manner, and will provide a powerful new strategy for tailoring of material properties via biomineralization.
关键词: Biomineralization,Titanium dioxide,Photocatalyst,in situ substitutional nitrogen-doping,Designer biotemplate
更新于2025-09-23 15:23:52
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A Mechanical and modelling study of magnetron sputtered Cerium-Titanium Oxide film coatings on Si (100)
摘要: Ce/Ti mixed metal oxide thin films have well known optoelectrical properties amongst several other physio-chemical properties. Changes in the structural and mechanical properties of magnetron sputtered Ce/Ti oxide thin films on Si (100) wafers with different Ce:Ti ratios are investigated experimentally and by modelling. X-ray Photoemission Spectroscopy (XPS) and X-ray diffraction (XRD) confirm the primary phases as trigonal Ce2O3 and rutile form of TiO2 with SiO2 present in all prepared materials. FESEM imaging delivers information based on the variation of grain size, the mixed Ce/Ti oxides providing much smaller grain sizes in the thin film/substrate composite. Nanoindentation analysis concludes that the pure cerium oxide film has the highest hardness value (20.1 GPa), while the addition of excess titanium oxide decreases the hardness of the film coatings. High temperature in-situ XRD (up to 1000 °C) results indicate high thermal phase stability for all materials studied. The film with Ce:Ti = 68%:32% has a new additional minor oxide phase above 800 °C. Contact angle experiments suggest that the chemical composition of the surface is insignificant affecting the water contact angle. Results show a narrow band of 87.7o to 95.7o contact angle. The finite element modelling (FEM) modelling of Ce/Ti thin film coatings based on Si(100); Si(110); silica and steel substrates shows a variation in stress concentration.
关键词: in-situ X-ray diffraction,Finite element modelling,Nanoindentation,Cerium titanium oxides,Mechanical properties
更新于2025-09-23 15:23:52
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Photocatalytic degradation of organic pollutants from wastewater using aluminium doped titanium dioxide
摘要: The objective of this research was to study the performance of batch and continuous recirculating reactor to photo-degrade dye and synthetic wastewater. Here, Aluminium (Al) was used as the doped metal. The commercially available TiO2 P-25 and Al (NO3)3 was used as a Ti-precursor and doping agent, respectively, via the impregnation method. Various parameters such as the concentration of the doping agent, and calcination temperature were studied. The TiO2 nanocrystal doped with Al was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analyzer (TGA). The photocatalytic performance of Al-doped nanoparticle was quantified by the degradation of methylene blue (MB) solution under a visible light irradiation condition. Its performance was compared against undoped-nano-TiO2. The results showed that Al (NO3)3 solution with a concentration of 0.25% and volume of 100 cm/ml, and calcined at 300 C for 4 h, was the optimum condition of Al-doped nano-TiO2. Furthermore, the highest pseudo-first-order kinetic rate was 0.096 where the doped Al(NO3)3 of 0.75 w/v was used in the batch reactor. The Al-doped nano-TiO2 that was obtained has the potential for use as a photocatalyst for degradation organics pollutant from wastewater under the visible light irradiation. The highest removal of organic pollutants from synthetic wastewater was 75% using TiO2 P-25 alone at 2 g/L dosage. In addition, the removal of organic pollutant by TiO2/doped with Al was 80% at a dosage of 0.5 g/L and was 85% at a dosage of 1 g/L.
关键词: Batch reactor,Photo-catalyst,Titanium dioxide,Advanced oxidation process
更新于2025-09-23 15:23:52
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A brief overview of molecularly imprinted polymers supported on titanium dioxide matrices
摘要: Molecularly imprinted polymer (MIP) is a polymer competent of mimicking selective binding of target or template molecule, which is characteristic of enzyme and antibodies. MIP has a wide range of applications in various fields of science and can be used as a sensor, catalyst, drug delivery component, etc. To overcome some demerits of MIP, the process of formation of imprinting cavity was carried out by nanoimprinting materials, which enables the imprinting technique to create more effective recognition sites than those obtained by traditional approaches. Here, in this article, we described a brief account of various discoveries happened in titanium dioxideebased molecularly imprinted polymeric system that shows a wide variety of chemical applications. The intention of this article is to provide comprehensive knowledge and information to all researchers who are interested in exploiting molecular imprinting technology toward the rational design of various chemical sensors operating on different transduction principles, ranging from electrochemical to piezoelectric, being used for the detection of different template molecules as they pose considerable impact on the understanding of the origin of life and all processes that occur in living organisms.
关键词: Applications,Titanium dioxide,Molecular imprinting,Imprinted structures
更新于2025-09-23 15:23:52
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Water-soluble titanium-oxides: Complexes, clusters and nanocrystals
摘要: The water-soluble titanium-oxide structures covered in this review span a continuum from molecular clusters to colloidal nanocrystals. Here, a deliberate distinction is made between titanium clusters and nanoparticles with organic ligands, soluble in organic solvents, and related structures prepared and soluble in water. This distinction is made in response to rapid developments in three areas covered in this article: small titanium-oxide clusters prepared at low pH values in water, heterpolytungstate macroanions with high-nuclearity titanium-oxide cores, and polyoxometalate complexes of anatase-phase TiO2. The latter nanostructures occupy a unique position between polyoxometalate macroanions and traditional colloidal TiO2. As such, the progressively larger water-soluble titanium-oxide structures covered in the three main sections of this review establish a continuum that begins to blur the longstanding divide between molecular and colloid science.
关键词: Polyoxometalates,Titanium oxide,Water soluble,Clusters,Nanocrystals
更新于2025-09-23 15:23:52
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Enzymatic sensor for phenols based on titanium dioxide generating surface confined ROS after treatment with H2O2
摘要: Titanium dioxide (TiO2) is a popular material as host matrix for enzymes. We now evidence that TiO2 can accumulate and retain reactive oxygen species after treatment by hydrogen peroxide (H2O2) and support redox cycling of a phenolic analyte between horseradish peroxidase (HRP) and an electrode. The proposed detection scheme is identical to that of second generation biosensors, but the measuring solution requires no dissolved H2O2. This significantly simplifies the analysis and overcomes issues related to H2O2 being present (or generated) in the solution. The modified electrodes showed rapid stabilization of the baseline, a low noise level, fast realization of a steady-state current response, and, in addition, improved sensitivity and limit of detection compared to the conventional approach, i.e. in the presence of H2O2 in the measuring solution. Hydroquinone, 4-aminophenol, and other phenolic compounds were successfully detected at sub-μM concentrations. Particularly, a linear response in the concentration range between 0.025 and 2 μM and LOD of 24 nM was demonstrated for 4-aminophenol. The proposed sensor design goes beyond the traditional concept with three sensors' generations offering a new possibility for the development of enzymatic sensors based on peroxidases and the formation of ROS on titania after treatment with H2O2.
关键词: Hydroperoxyl species,Titanium dioxide,Horseradish peroxidase,Bioelectrochemistry,Hydrogen peroxide
更新于2025-09-23 15:23:52
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Adsorption and photocatalytic oxidation of ibuprofen using nanocomposites of TiO2 nanofibers combined with BN nanosheets: Degradation products and mechanisms
摘要: This study investigated the adsorption and photocatalytic activity of TiO2-boron nitride (BN) nanocomposites for the removal of contaminants of emerging concern in water using ibuprofen as a model compound. TiO2 nanofibers wrapped by BN nanosheets were synthesized by electrospinning method. Characterization of the nanocomposite photocatalysts indicated the BN nanosheets improved the light absorbance and reduced the recombination of the photoexcited charge carriers (e- and h+). The photocatalytic oxidation products and mechanisms of ibuprofen by the TiO2-BN catalysts were elucidated using a multiple analysis approach by high performance liquid chromatography, ultraviolet absorbance, dissolved organic carbon, fluorescence excitation-emission matrices, and electrospray ionization–liquid chromatography–tandem mass spectrometry. The experimental results revealed that the photocatalytic oxidation by the TiO2-BN nanocomposites is a multi-step process and the interactions between ibuprofen molecules and the TiO2-BN nanocomposites govern the adsorption process. The increasing BN nanosheet content in the TiO2 nanofibers facilitated the breakdown of ibuprofen degradation intermediates (hydroxyibuprofen, carboxyibuprofen, and oxypropyl ibuprofen). Kinetic modeling indicated both adsorption and photocatalytic oxidation of ibuprofen by the TiO2-BN nanocomposites followed the first-order kinetic model. The photocatalytic oxidation rate increased with the increasing BN content in the nanocomposite catalysts, which was attributed to the enhanced light absorption capacity and the separation efficiency of the photoexcited electron (e-)-hole (h+) pairs. Multiple photocatalytic cycles were conducted to investigate the reusability and regeneration of the nanofibers for ibuprofen degradation.
关键词: adsorption,titanium dioxide boron-nitride nanocomposites,photocatalytic degradation mechanisms,degradation intermediates,photocatalytic oxidation
更新于2025-09-23 15:23:52