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Surface Photocatalytic Research of Fe -doped TiO2 (001) Based On the First-principles
摘要： In this paper,the first-principles based on density functional theory was used to study the Fe/TiO2(001) band gap width and adsorption energy of C6H6 molecules at different positions on the surface of the molecule with different doping methods and different Fe content. Calculation of the band structure and density of states of Fe-doped TiO2 nanoparticles shows that, the surface gap doping is more favorable than the substitution doping to reduce the band gap of TiO2,and when the doping concentration is 6.122%,the maximum reduction of the band gap width is 59.3% higher than that of pure TiO2.According to the comparement of adsorption energy, it works out that the benzene molecule is mainly about horizontal adsorption on the surface of TiO2(001).Within the scope of the study, with the increase of Fe doping concentration, The adsorption energy does not decrease as the band gap, when the Fe atoms doping concentration is 4.167%,the maximum increase of adsorption energy is 63.2%.
关键词： photocatalytic,Fe-doped TiO2,band gap,first-principles,adsorption energy
更新于2025-09-23 15:21:01
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AIP Conference Proceedings [Author(s) 3RD INTERNATIONAL SCIENCES, TECHNOLOGY & ENGINEERING CONFERENCE (ISTEC) 2018 - MATERIAL CHEMISTRY - Penang, Malaysia (17–18 April 2018)] - Influence of calcination temperature on the characteristic and sonophotocatalytic activities of Fe-doped TiO2 particles
摘要： In this study, 3 wt% Fe-doped TiO2 particles were prepared by sol-gel method using tetrabutyl titanate and iron (III) nitrate nonahydrate as precursors. Calcination of the prepared samples was carried out at temperature of 200, 400, 600 and 800 °C for 2 h. The effect of calcination temperature on the composition, structure and morphology of Fe-doped TiO2 were characterized using Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray Spectroscope (EDX) and X-ray Diffractometer (XRD). The FESEM images revealed changes in particle size from 34 to 148 nm for samples calcined at 200 to 800 °C, respectively. Meanwhile, XRD results demonstrated the presence of rutile phase in catalysts which were calcined above 600 °C. Sonophotocatalytic degradation of paracetamol using ultraviolet (UV) light and ultrasonic irradiation was performed to investigate the influence of calcination temperature on the catalytic activity of Fe-doped TiO2. Among all the calcined catalysts, the Fe-doped TiO2-600 achieved the highest degradation efficiency (74%) due to the presence of mixed anatase and rutile phases. This proved that calcination temperature is a critical parameter which affects the characteristics and catalytic activity of Fe-doped TiO2 catalyst in the sonophoto-degradation process.
关键词： Paracetamol,Sonophotocatalytic,Heat treatment,Fe-doped TiO2,Characteristics
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE 7th International Conference on Photonics (ICP) - Langkawi, Malaysia (2018.4.9-2018.4.11)] 2018 IEEE 7th International Conference on Photonics (ICP) - Modal Properties of a Varied High Indexed Large Core 4-Mode Photonic Crystal Fiber
摘要： A varied high indexed, large core 4-mode photonic crystal fiber is proposed. Consequences of variation in the refractive index of the materials used in the rings have been analyzed through the far field distribution and phase of each mode. The influence of different, air hole diameters and distances between the holes of the fiber is studied.
关键词： refractive index,germanium doped fiber,photonic crystal fiber,design
更新于2025-09-23 15:21:01
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Atomic and electronic structure of ferroelectric La-doped HfO<sub>2</sub> films
摘要： The atomic structure and optical properties of ferroelectric La-doped hafnium oxide (La:HfO2) thin films grown by the plasma-assisted atomic layer deposition were investigated. Using high resolution transmission electron microscopy, it was shown that the studied La:HfO2 film has a orthorhombic polar structure with the P mn21 space group. It was found that the film exhibits ferroelectric properties. By means of X-ray photoelectron spectroscopy and specroellipsometry it was established that La:HfO2 consists of the HfO2 and La2O3 phases mixture. The specroellipsometry analysis with the Bruggeman effective medium approximation showed that the investigated La:HfO2 consists of 88% HfO2 and 12% La2O3. It is shown that etching La:HfO2 with argon ions leads to the oxygen vacancies generation in the near-surface region. These vacancies are generated mainly due to the knocking out of oxygen atoms to the interstitial positions, and the following annealing at 700 ℃ in vacuum for 1 hour leads to the annihilation of that Frenkel defects.
关键词： ferroelectric,XPS,electronic structure,plasma-assisted atomic layer deposition,atomic structure,La-doped HfO2,specroellipsometry,HRTEM
更新于2025-09-23 15:21:01
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Improving Interfacial Charge-Transfer Transitions in Nb-Doped TiO2 Electrodes with 7,7,8,8-Tetracyanoquinodimethane
摘要： Interfacial charge-transfer (ICT) transitions involved in charge-separation mechanisms are expected to enable efficient photovoltaic conversions through one-step charge-separation processes. With this in mind, the charge-transfer complex fabricated from TiO2 nanoparticles and 7,7,8,8-tetracyanoquinodimethane (TCNQ) has been applied to dye-sensitized solar cells. However, rapid carrier recombination from the conduction band of TiO2 to the highest occupied molecular orbital (HOMO) of TCNQ remains a major issue for this complex. In this study, to inhibit surface-complex recombinations, we prepared Nb-doped TiO2 nanoparticles with different atomic ratios for enhanced electron transport. To investigate the effects of doping on electron injection through ICT transitions, these materials were examined as photoelectrodes. When TiO2 was doped with 1.5 mol % Nb, the Fermi level of the TiO2 electrode shifted toward the conduction band minimum, which improved electron back-contact toward the HOMO of TCNQ. The enhancement in electron transport led to increases in both short circuit current and open circuit voltage, resulting in a slight (1.1% to 1.3%) improvement in photovoltaic conversion efficiency compared to undoped TiO2. Such control of electron transport within the photoelectrode is attributed to improvements in electron injection through ICT transitions.
关键词： photovoltaic conversion,Nb-doped TiO2,interfacial charge-transfer transition,7,7,8,8-tetracyanoquinodimethane
更新于2025-09-23 15:21:01
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Poly (Vinyl Alcohol) Decorated Lithium Doped Stannous Oxide Nanocomposites as Highly Flexible UVA Shieldants
摘要： Herein, we report the successful fabrication of a series of mechanically flexible poly (vinyl alcohol) (PVA) nanocomposite films with varying amounts of lithium doped stannous oxide (Li0.4Sn0.8O) nanofillers (i.e., 0.0, 0.5, 1.0, 2.0 and 4.0 wt %) by mechanical shearing followed by film casting. The structural characterizations (FTIR) ascertain the success of lithium doped stannous oxide integrations with PVA matrix. While, electronic spectral studies sheds light on the changes in electronic band structure leading to a gradual decrease in optical band gaps associated electronic transition from valence band to conduction band. The UV-visible transmittance study substantiates the ability of nano fabricated polymeric films to efficiently shield UV radiations, in particular UVA radiations and thereby act as highly flexible and visible transparent UVA protective coatings.
关键词： Lithium doped stannous oxide,UVA protective coatings,Nano composite
更新于2025-09-23 15:21:01
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In situ fluorine doped ZrO2?x nanotubes for efficient visible light photocatalytic activity
摘要： The F-doped ZrO2?x nanotubes are synthesized by anodic oxidization in a F-containing electrolyte and following a low temperature annealing process. The F-doped ZrO2?x nanotubes exhibit a dramatic increase in visible light absorption and efficient visible light photocatalytic activity which are not possessed to normalized ZrO2. The fluorine in anodic ZrO2 nanotubes plays a vital role in the formation of abundant anion vacancies during the annealing. Combining the doping effect of the residual fluorine element, the band gap of the F-doped ZrO2?x nanotubes reduced from 5.13 to 2.35 eV. Moreover, the transient photocurrent response plots and the photocatalytic experiments reveal the highly effective electrons–holes separation of the F-doped ZrO2?x nanotubes and enhanced visible-light photocatalytic degradation for RhB. The degradation rate of RhB in the presence of the F-doped ZrO2?x nanotubes catalyst has reached up to 83% under 2 h low-power LED light irradiation. In addition, the possible photocatalytic mechanism of the F-doped ZrO2?x nanotubes has been proposed via studying the band structure. It is believed that the F-doped ZrO2?x nanotubes will have a bright future for sustainable energy sources and cleaning environment.
关键词： oxygen vacancies,F-doped ZrO2?x nanotubes,anodic oxidization,visible light photocatalytic activity,band gap narrowing
更新于2025-09-23 15:21:01
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Semiconductor Photocatalysis - Materials, Mechanisms and Applications || Photocatalytic Removal of Organics over BiVO4-Based Photocatalysts
摘要： Organic compounds, such as organic dyes and phenols, are the main pollutants in wastewater. In the past years, a large number of studies on the fabrication and photocatalytic organics degradation of BiVO4 and its related materials have been reported in the literature. In this chapter, we shall focus on the advancements in the synthesis and photocatalytic applications of several kinds of BiVO4-based photocatalysts: (i) well-defined morphological BiVO4 photocatalysts, (ii) porous BiVO4 photocatalysts, (iii) heteroatom-doped BiVO4 photocatalysts, (iv) BiVO4-based heterojunction photocatalysts, and (v) supported BiVO4 photocatalysts. We shall discuss the structure–photocatalytic performance relationship of the materials and the involved photocatalytic degradation mechanisms. In addition, we also propose the research trends and technologies for practical applications of the BiVO4-based photocatalytic materials.
关键词： BiVO4-based heterojunction,well-defined morphology,heteroatom-doped BiVO4,supported BiVO4,porous BiVO4 photocatalyst
更新于2025-09-23 15:21:01
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The fabrication of self-floating Ti3+/N co-doped TiO2/diatomite granule catalyst with enhanced photocatalytic performance under visible light irradiation
摘要： Powdery photocatalyst has long been investigated and developed, yet its disadvantages such as low light-harvesting and reuse capability in suspension system have greatly hindered its practical application. The proposal of floating photocatalyst provided an alternative method to overcome the above limitations. In this work, TiO2 nanoparticles were doped by Ti3+ and N, and dispersed onto natural porous mineral diatomite via sol-gel method. The obtained black powder was granulated to produce floating granule catalyst (black Ti3+/N co-doped TiO2/diatomite hybrid granule), denoted as b/N-TDHG. The synergy between Ti3+ and N dopants, as well as diatomite and TiO2 were studied. The photoactivity of b/N-TDHG was investigated via the degradation of antibiotic tetracycline (TC) solution under visible light irradiation, and then the optimal co-doping amount and granule dosage were determined. The optimal granule catalyst presented its removal rate of TC as 92.0% within 150 min, and its rate constant was 0.0144 min?1, while the corresponding powdery sample showed the removal rate of TC as 90.5% during the same period, with its rate constant as 0.0135 min?1. Moreover, floating b/N-TDHG could simply be filtrated from TC solution, and the removal rate slightly dropped to 89.6% after 5 repetitions, presenting good reusability.
关键词： Ti3+/N co-doped,Diatomite,Visible light,Self-floating,Tetracycline
更新于2025-09-23 15:21:01
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Optical properties of OH? doped 2Bi2O3–3GeO2 glass and crystal
摘要： The OH? doped 2Bi2O3–3GeO2 (Bi4Ge3O12, BGO) glass was prepared via conventional melt cast-quenching technique, and OH? doped Bi4Ge3O12 (BGO) crystal has been grown by Vertical Bridgman method for comparison. Absorption, transmittance, near infrared (NIR) emission, and XPS spectra were measured. The infrared transmittance spectra reflect the characteristics of OH? absorption in doped BGO glasses and crystals. Broad NIR emission (under excitation at 785 nm) centered at about 1300 nm was detected in OH? doped BGO glasses, and the measured fluorescent lifetime is several hundred microseconds. The introduced OH? might make Bi3+ lower valence ions. The XPS measurement of the Bi 4f region reveals that the NIR emission should be related to lower valence Bi ions. The OH? doped BGO glass with broad NIR emission may be used as effective amplifier for signals in silica fiber.
关键词： OH?,Luminescence,2Bi2O3–3GeO2,Doped
更新于2025-09-23 15:21:01