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Synthesis of 3D Hierarchical Structure TiO2 and Its Photocatalytic Activity
摘要： 3D hierarchical structure TiO2 can be synthesized via a solvothermal method using butyl titanate as precursor and acetic acid as solvent. The microspheres were characterized and analyzed by X-ray diffraction (XRD), electron microscope scanning (SEM), transmission electron microscope (TEM), N2 adsorption-desorption, the ultraviolet, X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL), ultraviolet and visible spectrophotometer (UV-Vis). The photocatalytic degradation performance was evaluated under the condition of methyl orange (MO) simulating wastewater. The results showed that the 3D hierarchical structure was one-step synthesized by the coordination of several surfactants, and as the time of solvent heat increases, morphology, and structure can be regulated from a 3D hierarchical structure to the grain-shaped, and the process of dissolution, recrystallization and orientated growth occurred during the course of reaction, which is different from the previous literature. The morphology of TiO2 can be regulated and controlled by reaction time. 3D hierarchical structure anatase TiO2 exhibited excellent photocatalytic activity in the degradation of organic compounds. The unit of hierarchy structure interconnected with each other, forming of various sizes of holes, which increase the specific surface area and are beneficial to the diffusion of the object molecules.
关键词： Solvothermal,Photocatalysis,3D hierarchical structure,Titania
更新于2025-09-09 09:28:46
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Influence of the Heat Treatment on the Particles Size and on the Crystalline Phase of TiO2 Synthesized by the Sol-Gel Method
摘要： Titanium biomaterials’ response has been recognized to be affected by particles size, crystal structure, and surface properties. Chemical and structural properties of these nanoparticle materials are important, but their size is the key aspect. The aim of this study is the synthesis of TiO2 nanoparticles by the sol-gel method, which is an ideal technique to prepare nanomaterials at low temperature. The heat treatment can affect the structure of the ?nal product and consequently its biological properties. For this reason, the chemical structure of the TiO2 nanoparticles synthesized was investigated after each heat treatment, in order to evaluate the presence of different phases formed among the nanoparticles. FTIR spectroscopy and XRD have been used to evaluate the different structures. The results of these analyses suggest that an increase of the calcination temperature induces the formation of mixed-crystalline-phases with different content of anatase and rutile phases. The results obtained by SEM measurements suggest that an increase in the particles size accompanied by a noticeable aggregation of TiO2 nanoparticles is due to high temperatures achieved during the thermal treatments and con?rmed the presence of different content of the two crystalline phases of titanium dioxide.
关键词： titania,sol-gel method,rutile,FTIR,nanoparticles size,anatase
更新于2025-09-09 09:28:46
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Photocatalytic and Antibacterial Activities of Silver and Iron Doped Titania Nanoparticles in Solution and Polyaspartic Coatings
摘要： Visible region active photocatalytic coatings are of interest for antimicrobial activity in low light applications or those employing LED lights with limited UV content. This work examined Ag and Fe doped titania nanoparticles (nTiO2) with varying dopant ranges in polyaspartic polymer coatings for potential light and dark activity. First, the Ag and Fe doped nTiO2 were synthesized by sol-gel chemistry with varying dopant concentrations, then characterized with respect to their size and aggregate size distribution, crystallinity, and surface and band gap features. The photocatalytic activity was then tested with methylene blue (MB) under both AM1.5G and visible light. From both sample sets (Ag and Fe doped nTiO2), the best photo catalytically active sample materials were chosen for antibacterial tests with gram negative Escherichia coli (E. coli) and gram positive Bacillus subtilis (B. subtilis) in (a) solution and (b) polyaspartic nanocomposites under UV and visible irradiation. The results showed that Ag doped nTiO2 samples delivered the best photocatalytic activity and excellent antibacterial action, even in the dark, attributed to both an enhanced band gap and surface area, as well as a combination of photocatalytic activity and Ag being present at the nanoparticle’s (NP) surface. No leaching of Ag at room temperature was observed from the nTiO2 structure, giving potential for next generation coatings that are both light and dark active.
关键词： Fe doping,polyaspartic composites,antibacterial activity,photo-catalysis,Ag doping,nanoparticles,Titania
更新于2025-09-09 09:28:46
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Nanostructured Titania Templated by Natural Cellulose Substance: Effect of Vanadium-Doping on the Anatase-to-Rutile Phase Transformation
摘要： Vanadium-doped rutile titania nanomaterial was synthesized by calcination of titania/vanadia composite thin gel films pre-coated natural cellulose substance (e.g., ordinary filter paper) at a relatively low temperature (600 °C). A better mixture of titanium and vanadium species is achieved during the layer-by-layer (LbL) deposition process with cellulose nanofiber as a template, leading to more vanadium dopants incorporated in the titania crystal lattices. By sufficient vanadium-doping, the phase transformation temperature from anatase to rutile phase of titania is decreased effectively. The doping mode and existing state of vanadium in the titania nanomaterials and the effect on the anatase-to-rutile phase transformation have been studied. This strategy provides a facile and effective route to facilitate the phase transformation of various nanostructured metal oxides templated by natural cellulose substance through doping appropriate functional metal ions in the LbL deposition process.
关键词： Biomimetic,Ceramics,Sol–Gel Preparation,Phase Transformation,Titania
更新于2025-09-04 15:30:14
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Nano Structured Ni and Ru Impregnated TiO <sub/>2</sub> Photocatalysts: Synthesis, Characterization and Photocatalytic Degradation of Neonicotinoid Insecticides
摘要： Titania by sol gel and Ni–Ru titania catalysts by wet impregnation methods were prepared and characterized by XRD, UV-DRS, BET and TEM techniques. Catalytic activities of the photocatalysts were evaluated towards the degradation of three widely used neonicotinoids type insecticides namely acetamiprid, imidacloprid and thiamethoxam under UV, Visible and solar irradiations. The reaction parameters such as initial concentration of the insecticide, weight of the catalyst and pH of the system were found to influence the reaction rate. The results indicated that the metal impregnated catalysts were found to be more active than pure TiO2. Ni/TiO2 or Ru/TiO2 catalysts degraded all the insecticides completely even under visible irradiation. The observed visible activity of the catalysts was attributed to their lower band gap values. HPLC and TOC analyses revealed that mineralisation of the insecticides occurred through dearomatization by multiple hydroxylation and oxidation. The degradation pathway and the kinetics were also discussed in detail.
关键词： HPLC,Photocatalysis,Sol–Gel Method,Titania,Neonicotinoids,Insecticides
更新于2025-09-04 15:30:14
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Effects of Operating Parameters on Photocatalytic Degradation of Methylene Blue or Phenol on Supported Titanium-Based Catalysts
摘要： Photocatalytic decompositions of both methylene blue and phenol in aqueous solutions were conducted separately on titanium-based catalysts. The catalysts were prepared using impregnation method on different supports (SiO2, Al2O3 or ZSM-5) and titanium precursors (TiO2 or TiCl4). They were tested in visible light or UV irradiations of different wavelengths (254 and 365 nm). The physico-chemical characteristics of the catalysts were obtained using BET, XRD, FTIR and TGA. The supports surface areas and porosities showed insignificant decreased after impregnation with the active components. The diffraction patterns showed strong peaks that are assigned to titania anatase phase and weaker peak that indicated low concentration of rutile phase. Irrespective of the support, FTIR showed broad peaks of Ti-O-Ti linkages in TiO2 particles. The catalysts were found to be active in decomposition of either methylene blue or phenol from aqueous solutions. For both methylene blue and phenol, the removal trend is TiO2/SiO2<TiO2/Al2O3<<TiO2/ZSM-5.
关键词： Titania,Phenol,Precursors,Methylene blue,Supports,Photocatalysis
更新于2025-09-04 15:30:14
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Photocatalytic Degradation of Aniline Using Supported TiO2/Charcoal Composite
摘要： TiO2/bamboo charcoal composites were prepared by sol-gel technique with tetrabutyl titanate as the titanium source and 60-mesh bamboo charcoal as the support. The photocatalytic degradation processes of aniline were studied. The results indicated that the TiO2/bamboo charcoal composites had quite a good photocatalytic ability. In the UV irradiation, the temperature and pH value had great influence on the effect of degradation. When the pH value was between 1 to 3 and the temperature was 50 oC, the degradation effects reached more than 93 %. The degradation rate of aniline decreased when the concentration increased but increased with more TiO2 in it. The degradation achieved balance after 105 min. The photocatalytic degradation of aniline to TiO2 fitted in with the first reaction kinetic equation.
关键词： Aniline,Titania,Bamboo charcoal,Photocatalytic degradation
更新于2025-09-04 15:30:14
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Enhancing Solar‐Driven Water Splitting with Surface‐Engineered Nanostructures
摘要： Functional nanoscale interfaces that promote the transport of photoexcited charge carriers are fundamental to efficient hydrogen production during photoelectrochemical (PEC) splitting of water. Here, the realization of a functional one-dimensional nanostructure achieved through surface engineering of hematite (α-Fe2O3) nanorods with a TiO2 overlayer is reported. The surface-engineered hematite nanostructure exhibits significantly improved PEC performance as compared to untreated α-Fe2O3, with an increase in the maximum incident photon-to-current efficiency (IPCE) of nearly 400% at 350 nm. While addition of the TiO2 overlayer did not alter the lifetime of photoexcited charge carriers, as evidenced from transient absorption spectroscopy, it is found that the presence of TiO2 could enhance oxygen electrocatalysis by interfacial electron enrichment, largely attributed to enhanced O(2p)(cid:1)Fe(3d) hybridization. Moreover, the interfacial electronic structure revealed from XANES measurements of the α-Fe2O3/TiO2 nanorods suggests that photoexcited holes in α-Fe2O3 may efficiently transfer through the TiO2 overlayer to the electrolyte while electrons migrate to the external circuit along the one-dimensional nanorods, thereby promoting charge separation and enhancing PEC splitting of water.
关键词： photoelectrochemical water splitting,titania,surface engineering,hematite,nanostructure
更新于2025-09-04 15:30:14
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Preparation and characterization of a novel nanocomposite coating based on sol-gel titania/hydroxyapatite for solid-phase microextraction
摘要： In this work a novel nanocomposite coating with high thermal stability and high durability is prepared. The surface of the stainless steel as a support was initially modified by (3–mercaptopropyl)trimethoxysilane. Surface characteristics of pure titania (TiO2), pure hydroxyapatite (HAP) and Hap/TiO2 nanocomposite coating were investigated and compared by energy dispersive X–ray (EDX) spectroscopy as well as by field emission–scanning electron microscopy (FESEM). The mutual effects of components on each other were discussed. Addition of HAP sol to the pure TiO2 sol, considerably changes the coating morphology. The applicability of the sol–gel HAP/TiO2 fiber was assessed for the headspace solid–phase microextraction (HS–SPME) of benzene, toluene, ethylbenzene and xylenes (BTEXs) from water sample followed by gas chromatography–mass spectrometry (GC–MS). Important parameters affecting the extraction efficiency were investigated. The efficiency of HAP/TiO2 nanocomposite coating was compared with other reported fibers and showed very good results. Under optimal conditions, the detection limits (S/N = 3) were in the range of 0.04 to 1 μg L?1, and the limits of quantification (S/N = 10) were between 0.1 and 4 μg L?1. The relative standard deviations (RSDs) for each fiber (at 20 μg L?1 and n = 5) were in the range of 1.76 to 8.18%, while the RSDs between fibers were 3.03 to 10.02%. The method showed a large linearity in the range from 0.1 to 1000 μg L?1 with correlation coefficients of > 0.995.
关键词： Gas chromatography–mass spectrometry,BTEX,Hydroxyapatite,Solid-phase microextraction,Sol–gel technology,Titania
更新于2025-09-04 15:30:14
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Modification of the Optical and Electronic Properties of TiO2 By N Anion-Doping for Augmentation of the Visible Light Assisted Photocatalytic Performance
摘要： In this work, a nitrogen-doped anatase TiO2 nanocrystal is prepared by a modified sol-gel preparation method using the nonionic surfactant (polyoxyethylene sorbitan monooleate) as a structural controller and a soft template. The as-prepared samples are characterized by X-ray diffraction, Raman spectroscopy, UV-Vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy techniques. Then the photocatalytic activity of these samples is assessed by the photocatalytic oxidation of phenol under visible light irradiation. The phenol concentration is measured using a UV-Vis spectrometer. Experimental results show that N-doping leads to an excellent visible light photocatalytic activity of the TiO2 nanocatalyst. Furthermore, the formation energy and electronic structure of pure and N-doped anatase TiO2 are described by density functional theory (DFT) calculations. It is found that N-doping narrowed the band gap of bare TiO2, which leads to an excellent visible light photocatalytic activity of N–TiO2 nanocatalysts. Therefore, the prepared N–TiO2 photocatalyst is expected to find the use in organic pollutant degradation under solar light illumination.
关键词： nitrogen doping,DFT simulation,photocatalysis,titania
更新于2025-09-04 15:30:14