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Enhanced Photocatalytic Activity of B, N-Codoped TiO <sub/>2</sub> by a New Molten Nitrate Process
摘要： B, N-codoped titania mesoporous crystals were prepared by the sol–gel method followed by a molten nitrate process to modify the sample morphology. The composition, morphology and microstructure of the obtained samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), Brunauer Emmett Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). Fourier Transform Infrared spectroscopy (FTIR) revealed weak complex vibrations between the Ti–O oxide species and the unsaturated sites (Ti3+) through the incorporation of hydroxyl groups, which was not observed in the bulk titania (B–N–TiO2). The photocatalytic reactivity of boron-nitrogen codoped TiO2 was examined for the removal of methylene blue (MB) under visible light irradiation. The nitrates treated B-doped TiO2 exhibited better photocatalytic activity for dye degradation than that of B-doped TiO2 and nitrates treated TiO2. The best performance was obtained in the sample treated at a calcination temperature of 550 °C.
关键词： Photocatalysis,Visible Light,Nitrate,Boron Doped Titanium Dioxide
更新于2025-09-09 09:28:46
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[IEEE 2018 33rd Symposium on Microelectronics Technology and Devices (SBMicro) - Bento Gon?alves, Brazil (2018.8.27-2018.8.31)] 2018 33rd Symposium on Microelectronics Technology and Devices (SBMicro) - On the influence of conductor, semiconductor and insulating substrate on the structure of atomic layer deposited titanium dioxide thin films
摘要： Titanium dioxide (TiO2) thin films were deposited on conductive (titanium and fluorine tin oxide glass), insulant (mica, cover glass and thermal SiO2 thin film on silicon) and semiconductive (silicon (100) and 4H-SiC) substrates by atomic layer deposition (ALD) technique. The metal and ligand precursors used were tetrachloride and water, respectively. Grazing incidence x-ray diffraction (GIXRD) analysis was performed to investigate the dependence of crystalline phase of the as-deposited thin films on different substrates for process temperatures ranging from 150-450oC. Results indicate that the ALD TiO2 crystalline phase is dependent on the substrate nature which modifies the required temperature for phase change, i.e. from amorphous to anatase to rutile. For example, for conductive substrates the temperature for formation of rutile phase is around 350 oC while for semiconductor substrates it was observed only from 400oC. By other hand, when the substrate has an amorphous structure there is not a common rule, i.e. for mica and thermal SiO2 thin film on silicon only anatase phase was formed in all temperature range investigated while, for cover glass, it was possible to observe all stages of TiO2 phase change, highlighting the formation of brookite phase for temperatures between 300 and 350°C. Moreover, it is shown that rutile phase can be obtained, in pure phase, at temperatures higher than 400oC, however only for glass and titanium substrates. These results allow us to infer that less expensive Ti thin film could act as a good seed layer for growth of good quality rutile TiO2 phase, by using ALD process on Si substrate and using precursors such as TiCl4 and H2O.
关键词： substrate type,titanium dioxide,GIXRD,atomic layer deposition
更新于2025-09-09 09:28:46
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How To Correctly Determine the Band Gap Energy of Modified Semiconductor Photocatalysts Based on UV–Vis Spectra
摘要： A misuse of the Tauc plot to determine the band gap energy of semiconductors may lead to erroneous estimates. Particularly large errors can be associated with characterization of modified semiconductors showing a significant absorption of sub-band gap energy photons. Taking the model methyl orange/titanium dioxide system, we address the problem and discuss how to apply the Tauc method correctly.
关键词： band gap energy,UV?Vis spectra,Tauc plot,methyl orange,modified semiconductors,titanium dioxide
更新于2025-09-09 09:28:46
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Photocatalytic Decolorization of Cobalamin in Aqueous Suspensions of TiO2 and ZnO Under Solar Irradiation
摘要： Photolysis and photocatalysts treatments of aqueous solution of cobalamin were carried out over a suspension of titanium dioxide and zinc oxide. Heterogeneous photocatalytic processes applied under natural weathering conditions, in the presence of solar radiation show a promising degradation capability. Under solar radiation a complete removal of color was achieved in a relatively short time of about 10 minutes, when ZnO was used and in 45 min when TiO2 was used. However, in the presence of artificial UV-light, complete decolorization of cobalamin was obtained in 20 min of irradiation when ZnO was used and in 60 min, when TiO2 was used at the same temperature. The results indicate that the degree of photocatalytic decolorization of cobalamin was obviously affected by different parameters such as, catalyst mass, type of catalyst and addition of H2O2.
关键词： Titanium dioxide,Zinc oxide,Cobalamin,Solar,Photocatalytic reactions,Decolorization efficiency
更新于2025-09-09 09:28:46
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Green Synthesis of High Temperature Stable Anatase Titanium Dioxide Nanoparticles Using Gum Kondagogu: Characterization and Solar Driven Photocatalytic Degradation of Organic Dye
摘要： The present study reports a green and sustainable method for the synthesis of titanium dioxide (TiO2) nanoparticles (NPs) from titanium oxysulfate solution using Kondagogu gum (Cochlospermum gossypium), a carbohydrate polymer, as the NPs formation agent. The synthesized TiO2 NPs were categorized by techniques such as X-Ray Diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy analysis, Raman spectroscopy, scanning electron microscope- Energy-dispersive X-ray spectroscopy (SEM-EDX), Transmission electron microscopy (TEM), High-resolution transmission electron microscopy (HR-TEM), UV-visible spectroscopy, Brunauer-Emmett-Teller (BET) surface area and particle size analysis. Additionally, the photocatalytic actions of TiO2 NPs were assessed with regard to their ability to degrade an organic dye (methylene blue) from aqueous solution in the presence of solar light. Various parameters affecting the photocatalytic activity of the TiO2 NPs were examined, including catalyst loading, reaction time, pH value and calcination temperature of the aforementioned particles. This green synthesis method involving TiO2 NPs explores the advantages of inexpensive and non-toxic precursors, the TiO2 NPs themselves exhibiting excellent photocatalytic activity against dye molecules.
关键词： methylene blue,titanium dioxide nanoparticles,gum kondagogu,green synthesis,photocatalysis
更新于2025-09-09 09:28:46
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Synthesis of N-F-codoped TiO2/SiO2 nanocomposites as a visible and sunlight response photocatalyst for simultaneous degradation of organic water pollutants and reduction of Cr (VI)
摘要： A new N-F-codoped TiO2/SiO2 nanocomposite was prepared by simple sol-gel method, and strongly stabilized on a substrate used in a fabricated photoreactor. The prepared photocatalysts were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, diffuse re?ectance UV/Vis, photoluminescence, ?eld emission scanning electron microscope, energy dispersive X-ray, transmission electron microscope, and N2 adsorption/desorption methods. The effective parameters of pH, ?ow rate of the incoming current, and the photoreactor tubes angle against sunlight were optimized. The photocatalytic performance of prepared photocatalysts was evaluated by studying the simultaneous removal of a mixture containing three azo dyes and Cr (VI) in the fabricated continuous-?ow photoreactor under visible and solar irradiation. The performance of the designed system was also proved under various outdoor climate conditions. Total organic carbon and ?ame atomic absorption spectroscopy analysis were performed on the treated sample to con?rm the decontamination of the model pollutant mixture. It was found that doping N and F in TiO2/SiO2 nanoparticles caused least agglomeration, enhanced activity under visible and solar irradiation, and fully anatase crystalline structure in the as-synthesized nanoparticles.
关键词： Titanium dioxide,N-F-codoped,Reduction of Cr (VI),Organic water pollutants,Photocatalysis
更新于2025-09-09 09:28:46
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Oxidation of off flavor compounds in recirculating aquaculture systems using UV-TiO2 photocatalysis
摘要： Geosmin (GSM) and 2-methylisoborneol (MIB) are secondary metabolites of cyanobacteria that are often present in recirculating aquaculture systems (RAS) and are problematic, even at low (ng L-1) concentrations, due to their taste and odor effects on water and accumulation in the lipid tissue of fish. Removal of these compounds is difficult due to their extremely low concentrations and advanced treatment technologies, such as advanced oxidation processes (AOPs) have to be employed. In this study, a novel AOP consisting of immobilized TiO2 in a UV reactor was tested at bench scale for removal of GSM and MIB in both batch and continuous flow modes. Batch reactor application at a full-scale RAS resulted in average GSM and MIB removal efficiencies of 61% and 72%, respectively, with a 6 hour treatment time. No significant removal of GSM and MIB was observed in continuous flow mode, most likely due to both lower residence time and low initial concentrations of both compounds. No negative effects were observed on downstream biological wastewater treatment processes, indicating that the proposed UV-TiO2 process can be safely integrated into RAS.
关键词： Titanium dioxide,Photocatalysis,Geosmin,Off-flavor compounds,Recirculating Aquaculture Systems,2-methylisoborneol
更新于2025-09-09 09:28:46
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Ink-jet printing of a TiO2–10%ZrO2 thin film for oxygen detection using a solution of metal alkoxoacetylacetonates
摘要： A solution of metal alkoxoacetylacetonates in isoamyl alcohol was used as a functional ink for ink-jet printing of TiO2-10%ZrO2 thin nanostructured films. It is shown that the anatase crystal lattice is formed during heat treatment of xerogel thin films in air at a temperature of 500 °C. According to the SEM scanning electron microscopy, the particle size of the resulting films was 10-11 nm. The effect of the number of TiO2-ZrO2 deposited layers on resulting 2D nanomaterial sensitivity to oxygen and other analyte gases (H2, CH4 and CO) at temperatures of 400 and 450 °C is shown.
关键词： Gas sensor,Sol-gel,Titanium dioxide,Additive,Ink-jet printing,Alkoxoacetylacetonate
更新于2025-09-09 09:28:46
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Enhanced Visible Light Sensitization of N-doped TiO2 Nanotubes Containing Ti-Oxynitride Species Fabricated via Electrochemical Anodization of Titanium Nitride
摘要： The concentration and chemical state of nitrogen represent critical factors to control the band-gap narrowing and the enhancement of visible light harvesting in nitrogen-doped titanium dioxide. In this study, photocatalytic TiO2-N nanoporous structures were fabricated by the electrochemical anodization of titanium nitride sputtered films. Doping was straightforwardly obtained by oxidizing as-sputtered titanium nitride films containing N-metal bonds varying from 7.3 to 18.5 % in the Ti matrix. Severe morphological variations into the as-anodized substrates were registered at different nitrogen concentration and studied by Small-Angle X-ray Scattering. Titanium nitride films with minimum N content of 6.2 at% N led to a quasi-nanotubular geometry, whilst an increase in N concentration up to 23.8 at% determined an inhomogeneous, polydispersed distribution of nanotube apertures. The chemical state of nitrogen in the TiO2 matrix was investigated by X-ray Photoelectron Spectroscopy depth profile analysis and correlated to the photocatalytic performance. The presence of Ti-N and β-Ti substitutional bonds, as well as Ti-oxynitride species was revealed by the analysis of N 1s X-ray Photoelectron Spectroscopy High Resolution spectra. The minimum N content of 4.1 at% in the TiO2-N corresponded to the lowest Ti-oxynitride ratio of 13.5 %. The relative variation of N-metal bonds was correlated to the visible light sensitization and the highest Ti-N/Ti oxynitride ratio of 3.3 was attributed to the lowest band-gap of 2.7 eV and associated to a threefold increase in the degradation of organic dye. Further increase of N doping led to a dramatic drop of Ti-N/Ti oxynitride ratio, from 3.3 to 0.4, which resulted in a loss photocatalytic activity. The impact of the chemical state of nitrogen towards efficient doping of TiO2 nanotubes is demonstrated with a direct correlation to the N loading and a strategy to optimise these factors based on a simple, rapid synthesis from titanium nitride.
关键词： visible light sensitization,photocatalytic performance,titanium nitride,nitrogen-doped titanium dioxide,electrochemical anodization
更新于2025-09-04 15:30:14
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PHOTOELECTROCHEMICAL ANALYSIS OF TITANIUM DIOXIDE BY USING OXALIC ACID AS A SACRIFICIAL DONOR
摘要： Photoelectrochemical (PEC) water splitting is a very promising green method to produce solar fuel. Titanium dioxide (TiO2) has been widely used as photocatalyst for this type of reaction. Improving the performance of TiO2 for PEC water splitting has been ongoing and addition of sacrificial donor especially from waste is an attractive option to achieve this. Oxalic acid is one component in organic waste stream that can be used as sacrificial donor. The TiO2 thin films has been fabricated by coating TiO2 paste on Fluorine Tin oxide (FTO) glass surface. The morphology of the TiO2 thin films were porous and rough with uniform particles size with crystallite size of about 20 nm and dominant anatase peak. The TiO2 photoelectrode undergo PEC testing to measure its photolectroactivity by using oxalic acid as a sacrificial donor in two different type of electrolytes which are distilled water and sodium sulfate (NA2SO4) aqueous solution. The photocurrent produced without addition of oxalic acid is much lower than with the acid. The saturation photocurrent for aqueous NA2SO4 solution and water electrolyte is 0.1 mA/cm2 and negligible respectively. While the photocurrent for addition of oxalic acid in NA2SO4 aqueous solution is 0.5 mA/cm2 and the photocurrent for oxalic acid in water only is 0.9 mA/cm2, which is almost double compared to in NA2SO4 and tenfold in water only. The highest photocurrent produced by TiO2 photoelectrode is by addition of oxalic acid in aqueous (H2O) electrolyte.
关键词： photoelectrochemical cell,titanium dioxide,donor,oxalic acid,Water splitting
更新于2025-09-04 15:30:14