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Photocatalytic Degradation of Reactive Dyes Over Titanates
摘要： MTiO3 (M = Sr, Ca, Ba and Pb) catalysts were synthesized by polymeric precursor method and characterized by using various instrumental techniques such as X-ray diffraction (XRD), UV-diffuse reflectance spectroscopy (UV-DRS), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). TiO2 were also synthesized by sol–gel method and used for the optimization of reaction parameters such as catalyst weight, dye concentration and pH in the photocatalytic degradation of reactive dyes such as reactive blue 198 (RB 198), reactive black 5 (RB 5) and reactive yellow 145 (RY 145) under UV irradiation. MTiO3 (M = Sr, Ca, Ba and Pb) catalysts were evaluated towards the photocatalytic decolourization of RB 198, RB 5 and RY 145 under optimized reaction conditions. Among the different metal titanates, strontium titanate showed the highest decolourization (≈90%) of all the three reactive dyes under UV irradiation at 120 minutes and also found to be active under visible irradiation as it decolourises the dyes in about 450 minutes. The degradation rate of strontium titanate was monitored by TOC analyzer. Kinetic studies of the photocatalytic degradation of reactive dyes confirmed that the reaction followed the pseudo first order kinetics.
关键词： Perovskites,Reactive Dyes,Polymeric Precursor,UV-Visible Degradation,Sol–Gel
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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Periodic TiO2 Nanostructures with Improved Aspect and Line/Space Ratio Realized by Colloidal Photolithography Technique
摘要： This paper presents substantial improvements of the colloidal photolithography technique (also called microsphere lithography) with the goal of better controlling the geometry of the fabricated nano-scale structures—in this case, hexagonally arranged nanopillars—printed in a layer of directly photopatternable sol-gel TiO2. Firstly, to increase the achievable structure height the photosensitive layer underneath the microspheres is deposited on a re?ective layer instead of the usual transparent substrate. Secondly, an increased width of the pillars is achieved by tilting the incident wave and using multiple exposures or substrate rotation, additionally allowing to better control the shape of the pillar’s cross section. The theoretical analysis is carried out by rigorous modelling of the photonics nanojet underneath the microspheres and by optimizing the experimental conditions. Aspect ratios (structure height/lateral structure size) greater than 2 are predicted and demonstrated experimentally for structure dimensions in the sub micrometer range, as well as line/space ratios (lateral pillar size/distance between pillars) greater than 1. These nanostructures could lead for example to materials exhibiting ef?cient light trapping in the visible and near-infrared range, as well as improved hydrophobic or photocatalytic properties for numerous applications in environmental and photovoltaic systems.
关键词： TiO2,sub-wavelength structures,sol-gel,colloidal photolithography
更新于2025-09-04 15:30:14
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Resistance-switching properties of Bi-doped $$\hbox {SrTiO}_{3}$$SrTiO3 films for non-volatile memory applications with different device structures
摘要： SrTiO3 and Bi-doped SrTiO3 ?lms were fabricated with different device structures using the sol–gel method for non-volatile memory applications, and their resistance-switching behaviour, endurance and retention characteristics were investigated. SrTiO3 and Sr0.92Bi0.08TiO3 ?lms grown on Si or Pt have the same phase structure, morphologies and grain size; however, the grain size of the Sr0.92Bi0.08TiO3 ?lms grown on Si is slightly larger than those of the SrTiO3 ?lms grown on Si and the Sr0.92Bi0.08TiO3 ?lms grown on Pt. The SrTiO3 or Sr0.92Bi0.08TiO3 ?lms grown on Si or Pt all exhibit bipolar resistive-switching behaviour and follow the same conductive mechanism; however, the Ag/Sr0.92Bi0.08TiO3/Si device possesses the highest RHRS/RLRS of 105 and the best endurance and retention characteristics. The doping of Bi is conducive to enhance the RHRS/RLRS of the SrTiO3 ?lms; meanwhile, the Si substrates help improve the endurance and retention characteristics of the Sr0.92Bi0.08TiO3 ?lms.
关键词： SrTiO3,resistance-switching properties,Bi doping,device structure,sol–gel
更新于2025-09-04 15:30:14
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The enhancement of humidity sensing performance based on Eu-doped ZnO
摘要： In this work, a high performance impedance-type humidity sensor based on Europium-doped ZnO with abundant surface oxygen vacancy defects was synthesized by sol-gel method. Response of the Eu-doped ZnO with di?erent molar ratio were investigated by exposing them to humidity environments in wide range of 11–95% RH at room temperature. The Eu-doped ZnO (2 mol%) exhibits a three orders impedance change, along with short response/recovery time (5 s/19 s), low hysteresis and best linearity. Complex impedance spectra indicates that dopant Eu can enhance humidity sensing performance of ZnO, which is resulted from the introduction of Eu3+ ions into ZnO structure to produce more defects of surface oxygen vacancy and more active sites on the surface of ZnO. The results show that this is a feasible method to achieve high humidity sensing performance by Eu doped ZnO, which make it a promising candidate for humidity sensing materials and broaden the use of ZnO materials.
关键词： Eu dopant,Humidity sensors,Sol-gel,Zinc oxide
更新于2025-09-04 15:30:14
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Influence of silane coupling agent on the properties of UV curable SiO2-PMMA hybrid nanocomposite
摘要： This work reports the preparation of UV-curable organic–inorganic hybrid nanocomposites synthetized by sol–gel method with the aim of obtaining highly transparent anti-abrasive coatings with long-term storage and stability for the protection of organic light emitting diodes (OLEDs). The inorganic phase is composed of tetraethoxysilane (TEOS) condensed under acid catalysis and mixed with tetrafunctional acrylate monomer and oligomer. Vinyltriethoxysilane (VTES), 3-methacryloxypropyltrimethoxysilane (MEMO), and 3-mercaptopropyltriethoxysilane (MTMO) are used as silane coupling agent and hybrid network modifier. Among the various parameters influencing the structure and properties of the hybrid, this work focuses on the nature and amount of coupling agent and their influence in terms of transparency, mechanical properties, and stability of the formulation. An optimum can be found in the silica to coupling agent ratio. Low level of functionalization leads to hybrids displaying poor optical performances and stability due to the coalescence of silica domains. On the contrary, an excess of functionalization reduces the abrasion resistance and the silica network formation. Changing the organic pendant of coupling agents greatly influences the properties of the coating by promoting the organic–inorganic balance. Dense and flexible as well as mechanically resistant coatings can be obtained from similar formulation by simply tuning the nature of the coupling agent depending of the needs of the application.
关键词： Sol–gel,Abrasion resistance,Nanocomposite,Hybrid coatings,UV-curable
更新于2025-09-04 15:30:14
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[ACS Symposium Series] Raman Spectroscopy in the Undergraduate Curriculum Volume 1305 || Integration of Raman Spectroscopy in Undergraduate Instruction and Research at Pace University
摘要： The integration of Raman spectroscopy into undergraduate instruction and research at Pace University is discussed in this chapter. This includes the introduction of the principle of Raman instrumentation, first by theory through the use of Gaussian calculations and interpretation of readily available spectra and then using the instrument after the acquisition of a B&W Tek Miniram in 2012. The availability of the instrument allows students to expand their research in sol-gel, ionic liquid, pharmaceuticals, and biodiesel. The development of simple experiments to incorporate into laboratory classes and side-by-side comparisons of experimental results and theoretical calculations are also presented. The challenges and successes of having this instrument in our teaching facility are also described.
关键词： undergraduate instruction,ionic liquid,research,Raman spectroscopy,pharmaceuticals,sol-gel,B&W Tek Miniram,biodiesel,Pace University
更新于2025-09-04 15:30:14
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Near-ultraviolet excited Tm3+ and Dy3+ ions co-doped barium lanthanum silica oxide phosphors for white-light applications
摘要： Nowadays, trivalent rare-earth ions activated inorganic luminescent materials have been widely investigated owing to their important applications in solid-state lighting field. Tm3+ and Dy3+ ions single- or co-doped Ba3La6(SiO4)6 (BLSO) phosphor materials for white light application were synthesized by a citrate-based sol-gel method. The prepared samples were examined by X-ray diffraction (XRD), scanning electron microscopy and Fourier-transform infrared spectroscopy to analyze the phase purity, surface morphology and existence of functional groups, respectively. The XRD pattern confirmed that the BLSO host lattice exhibited a hexagonal crystal structure with P63/m (176) space group, which is well indexed with standard JCPDS data. From photoluminescence results, the BLSO:Tm3+ phosphors exhibited purplish blue emission at 453 nm (1D2/3F4) and the BLSO:Dy3+ phosphors showed predominant yellow emission at 575 nm (4F9/2 / 6H13/2) compared to their shoulder blue emission at 479 nm (4F9/2 / 6H15/2), indicating that the Dy3+ ions occupied lattice sites with low inversion symmetry. The determined Commission Internationale de I’Eclairage (CIE) (0.3391, 0.3302) values for the Tm3+ and Dy3+ co-doped BLSO phosphors were near to the standard sun light CIE values (0.33, 0.33) under near-ultraviolet (364 nm) excitation. The energy transfer process from Dy3+ to Tm3+ ions was discussed and it was proved by their corresponding decay curves. Additionally, thermal study was carried out for the optimized phosphor and it maintained superior thermal PL properties.
关键词： Citrate-based sol-gel technique,Ba3La6(SiO4)6 phosphors,Pure white emission,Thermal stability
更新于2025-09-04 15:30:14
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Recent advances in synthesis, properties, and applications of vanadium oxide nanotube
摘要： Vanadium oxide nanotube is a new type of nanotubular material which opens new horizons for application in many areas. The important catalytic and electrochemical property of vanadium oxide as well as the unique shape of the nanotubes has been the impetus for studying this novel type of nanostructured material. The paper review focuses on recent advances of synthesis vanadium oxide nanotubes. Methods of synthesis vanadium oxide nanotubes (sol-gel, hydrothermal) of nanostructured-based on electrochemical and catalytic processes and metal dichalcogenides, Inorganic nanotubes, and oxide and hydroxide nanotubes and details the synthesis and structural properties of vanadium oxides get are reviewed.
关键词： Catalytic,Vanadium oxide,Sol-gel,Hydrothermal synthesis,Inorganic nanotubes,Nanostructured
更新于2025-09-04 15:30:14
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Luminescent mesoporous films containing europium III complex
摘要： Mesoporous materials have large speci?c area and pore volume, low density, and high mechanical and thermal stability. These materials can be applied as catalysts, shape-selective adsorbents, chemical sensors, and capsules for controlled release of therapeutic agents; they can also be employed in microelectronics, electro-optics, and other emerging nanotechnologies. In this study, we used the sol–gel process to obtain mesoporous silica ?lms by dip coating. A trispyrazolyl borate, or scorpionate (Tp), complex containing europium III was incorporated into a mesoporous silica ?lm via wet impregnation. The silica precursor solution was prepared by homogenizing tetraethylorthosilicate, deionized water, ethanol, and cetyltrimethylammonium bromide. The ?lms were obtained by the dip-coating technique (between one and two depositions) at a deposition rate of 300 mm/min; borosilicate glasses were used as substrates. The ?lms were characterized by X-ray di?raction, infrared spectroscopy, transmittance, and europium III photoluminescence analyses. X-ray di?raction showed that mesoporous silica was present in the substrate. Silica without thermal treatment and silica treated at 200 °C presented pore diameters of 3.75 and 3.45 nm, respectively. Thermal treatment eliminated the surfactant. The excitation and emission spectra con?rmed that the luminescent europium III complex was incorporated into the mesoporous silica ?lm, which can be employed as sensor.
关键词： Mesoporous ?lm,Luminescent sensor,Sol–gel,Dip coating
更新于2025-09-04 15:30:14