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Flame spray pyrolysis synthesized gold-loaded titanium dioxide photocatalyst for degradation of Rhodamine B
摘要： Gold-loaded titanium dioxide (Au-loaded TiO2) was synthesized by the flame spray pyrolysis method for using as photocatalyst. The synthesized Au-loaded TiO2 photocatalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The photocatalytic degradation of Rhodamine B (RhB) dye solution over synthesized Au-loaded TiO2 was studied. The concentration of RhB was determined by UV–Vis spectrophotometry. For the photocatalytic activity, it was found that Au(1.00 mol%)-loaded TiO2 was a better photocatalyst than others under the same reaction conditions. The optimal conditions for photocatalytic degradation of RhB were found to be 0.6 g/L of photocatalyst concentration under UV light irradiation (UV–C 254 nm). The highest kinetic rate constant of photocatalyst was 0.0057 min?1 at the optimum conditions and the mechanism of the photocatalytic process had also been discussed.
关键词： Rhodamine B,Flame spray pyrolysis,Au-loaded TiO2,Degradation,Photocatalyst
更新于2025-09-09 09:28:46
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[IEEE 2018 Iranian Conference on Electrical Engineering (ICEE) - Mashhad (2018.5.8-2018.5.10)] Electrical Engineering (ICEE), Iranian Conference on - Investigating the Electronic Properties of Oxygen Vacancies in Anatase TiO2: An Ab Initio Study
摘要： Metal oxide dielectrics are known as promising candidates for resistive switching or memristor applications. TiO2 has been shown to be one of the favorites for the implementation of resistive switching devices. The mobile oxygen vacancies in TiO2 are recognized as the main source of resistive switching behavior. Therefore, the investigation of atomic scale properties of oxygen vacancies is of crucial importance for the description of microscopic phenomena leading to the resistive switching behavior. In the present work we employed standard DFT within the GGA approximation as well as GGA+U correction to investigate the electronic properties of oxygen vacancies in anatase phase of TiO2. We show that the Hubbard- like term (U) is essential for the correct description of the electronic properties. The defect formation energies at different charged states and the charge transition levels are calculated for different values of U-term. It has been shown that a value of U=3.5 eV is the best choice to obtain reasonable results for the band gap as well as the position of induced defect levels, at same time. Moreover, we show that the q=+2 charged state is the energetically most favorable state for the oxygen vacancy in TiO2.
关键词： metal oxides,DFT,resistive switching,charge transition levels,oxygen vacancy,Hubbard-like term,anatase TiO2
更新于2025-09-09 09:28:46
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Modeling and Optimization of the Photocatalytic Reduction of Molecular Oxygen to Hydrogen Peroxide over Titanium Dioxide
摘要： This study focuses on understanding the mechanisms for optimization of the photocatalytic hydrogen peroxide production over TiO2 (Aeroxide P25). Via precise control of the reaction parameters (pH, temperature, catalyst amount, oxygen content, sacrificial electron donor and light intensity) it is possible to tune either the apparent quantum yield or the production rate. As a result of the optimization, apparent quantum yields of up to 19.8 % and production rates of up to 83 μM min-1 were obtained. We also observed a light dependent change of the reaction order and an interdependency of the light intensity and catalyst amount and developed a well-fitting kinetic model for it, which might also be applied to other reactions. Furthermore, a previously unreported inactivation of the photocatalyst in case of water oxidation is described.
关键词： titanium dioxide (TiO2),hydrogen peroxide (H2O2),oxygen reduction,catalyst inactivation,light intensity,photocatalysis
更新于2025-09-09 09:28:46
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Compositing Two-Dimensional Materials with TiO2 for Photocatalysis
摘要： Energy shortage and environmental pollution problems boost in recent years. Photocatalytic technology is one of the most effective ways to produce clean energy—hydrogen and degrade pollutants under moderate conditions and thus attracts considerable attentions. TiO2 is considered one of the best photocatalysts because of its well-behaved photo-corrosion resistance and catalytic activity. However, the traditional TiO2 photocatalyst suffers from limitations of ineffective use of sunlight and rapid carrier recombination rate, which severely suppress its applications in photocatalysis. Surface modification and hybridization of TiO2 has been developed as an effective method to improve its photocatalysis activity. Due to superior physical and chemical properties such as high surface area, suitable bandgap, structural stability and high charge mobility, two-dimensional (2D) material is an ideal modifier composited with TiO2 to achieve enhanced photocatalysis process. In this review, we summarized the preparation methods of 2D material/TiO2 hybrid and drilled down into the role of 2D materials in photocatalysis activities.
关键词： TiO2,composite,2D materials,photocatalysis
更新于2025-09-09 09:28:46
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Criticial Assessment of the Photocatalytic Reduction of Cr(VI) over Au/TiO2
摘要： The puri?cation of drinking water is one of the most urgent challenges in developing countries, for which the ef?cient removal of traces of heavy metals, e.g., Cr(IV), represents a key technology. This can be achieved via photocatalysis. In this study, we compare the performance of Au/TiO2 to bare TiO2 P25 catalysts. Furthermore, the in?uence of the sacri?cial reagent citric acid under UV-Vis and Vis excitation was investigated and a detailed investigation of the catalysts before and after reaction was performed. During the photocatalytic reduction of Cr(IV) under acidic conditions, both leaching of Au, as well as absorption of Cr, occur, resulting in new catalyst systems obtained in situ.
关键词： Au/TiO2,adsorption,photocatalysis,Cr(VI) reduction,citric acid
更新于2025-09-09 09:28:46
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Improved Microbial Electrolysis Cell Hydrogen Production by Hybridization with a TiO2 Nanotube Array Photoanode
摘要： A microbial electrolysis cell (MEC) consumes the chemical energy of organic material producing, in turn, hydrogen. This study presents a new hybrid MEC design with improved performance. An external TiO2 nanotube (TNT) array photoanode, fabricated by anodization of Ti foil, supplies photogenerated electrons to the MEC electrical circuit, signi?cantly improving overall performance. The photogenerated electrons help to reduce electron depletion of the bioanode, and improve the proton reduction reaction at the cathode. Under simulated AM 1.5 illumination (100 mW cm?2) the 28 mL hybrid MEC exhibits a H2 evolution rate of 1434.268 ± 114.174 mmol m?3 h?1, a current density of 0.371 ± 0.000 mA cm?2 and power density of 1415.311 ± 23.937 mW m?2, that are respectively 30.76%, 34.4%, and 26.0% higher than a MEC under dark condition.
关键词： hydrogen production,microbial electrolysis cell,TiO2 nanotube
更新于2025-09-09 09:28:46
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Hierarchical Ta-Doped TiO2 Nanorod Arrays with Improved Charge Separation for Photoelectrochemical Water Oxidation under FTO Side Illumination
摘要： TiO2 is one of the most attractive semiconductors for use as a photoanode for photoelectrochemical (PEC) water oxidation. However, the large-scale application of TiO2 photoanodes is restricted due to a short hole diffusion length and low electron mobility, which can be addressed by metal doping and surface decorating. In this paper we report the successful synthesis of hierarchical Ta doped TiO2 nanorod arrays, with nanoparticles on the top (Ta:TiO2), on F-doped tin oxide (FTO) glass by a hydrothermal method, and its application as photoanodes for photoelectrochemical water oxidation. It has been found that the incorporation of Ta5+ in the TiO2 lattice can decrease the diameter of surface TiO2 nanoparticles. Ta:TiO2-140, obtained with a moderate Ta concentration, yields a photocurrent of ～1.36 mA cm?2 at 1.23 V vs. a reversible hydrogen electrode (RHE) under FTO side illumination. The large photocurrent is attributed to the large interface area of the surface TiO2 nanoparticles and the good electron conductivity due to Ta doping. Besides, the electron trap-free model illustrates that Ta:TiO2 affords higher transport speed and lower electron resistance when under FTO side illumination.
关键词： hierarchical TiO2,photoelectrochemical water oxidation,Ta doping,charge separation
更新于2025-09-09 09:28:46
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Simple TiO <sub/>2</sub> Coatings by Sol–Gel Techniques Combined with Commercial TiO <sub/>2</sub> Particles for Use in Heterogeneous Photocatalysis
摘要： TiO2 coatings were obtained by a combination of a sol–gel process with the addition of commercial TiO2 particles (Degussa-Evonik P25). Simple and composite (with P25) sols were deposited by dip-coating on glass plates giving simple and composite coatings. The order of addition of reagents in the preparation of sols, the incorporation of P25 to the sols, and the thermal treatments were analyzed as variables to improve the photocatalytic activity. The samples were completely characterized with respect to the amount of deposited TiO2, the crystal structure (XRD) and the morphology (SEM). The activity of the supported photocatalysts (simple, composite and P25 coatings) was evaluated using 4-chlorophenol degradation and Cr(VI) reduction in the presence of EDTA as model photocatalytic systems. The stability of sols and the photocatalytic activity of the resulted coatings depended strongly on the order of addition of the reagents to obtain the simple sol. Sols prepared by adding the alcohol-water-HCl mixture to the precursor were the simple sols presenting a very good stability that permitted the incorporation of powdered P25 without the addition of additives. The composite coatings prepared from these simple sols were the most active in both photocatalytic systems and also presented the highest resistance to scratch.
关键词： TiO2 Films,Sol–Gel,Heterogeneous Photocatalysis
更新于2025-09-09 09:28:46
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Stone/Coating Interaction and Durability of Si-Based Photocatalytic Nanocomposites Applied to Porous Lithotypes
摘要： The use of hybrid nanocoatings for the protection of natural stones has received increasing attention over the last years. However, the interaction of these materials with stones and, in particular, its modification resulting from the blending of nanoparticles and matrices, are yet little explored. In this work, the interaction of two nanocomposite coatings (based on alkylalkoxysilane matrices and TiO2 nanoparticles in water and 2-propanol) with two different porous stones is examined in detail by comparing their absorption behaviour and protection performance with those of the respective TiO2-free matrices. It is shown that the protective effectiveness of both matrices is not negatively affected by the presence of TiO2, as the desired water barrier effect is retained, while a significant photocatalytic activity is achieved. The addition of titania leads to a partial aggregation of the water-based matrix and accordingly reduces the product penetration into stones. On the positive side, a chemical interaction between titania and this matrix is observed, probably resulting in a greater stability of nanoparticles inside the protective coating. Moreover, although an effect of TiO2 on the chemical stability of matrices is observed upon UV light exposure, the protective performance of coatings is substantially maintained after ageing, while the interaction between matrices and nanoparticles results in a good retention of the latter upon in-lab simulated rain wash-out.
关键词： UV ageing,stone protection,water-repellency,photo-oxidative degradation,durability,artificial rain,photocatalysis,TiO2 nanoparticles,alkylalkoxysilane
更新于2025-09-09 09:28:46
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Synthesis of Uniform Ordered Mesoporous TiO2 Microspheres with Controllable Phase Junctions for Efficient Solar Water Splitting
摘要： As a benchmark photocatalyst, commercial P25-TiO2 has been widely used for various photocatalytic applications. However, the low surface area and poorly porous structure greatly limit its performance. Herein, uniform ordered mesoporous TiO2 microspheres (denoted as Meso-TiO2-X, X represents the rutile percentage in the resulted microspheres) with controllable anatase/rutile phase junctions and radially oriented mesochannels were synthesized by a coordination-mediated self-assembly approach. The anatase/rutile ratio in the resultant microspheres can be facilely adjusted as desired (rutile percentage: 0–100) by changing the concentrations of hydrochloric acid. As a typical one, the yielded Meso-TiO2-25 microspheres have a similar anatase/rutile ratio with commercial P25. But the surface area (78.6 m2 g–1) and pore volume (0.39 cm3 g–1) of the resultant microspheres are larger than that of commercial P25. When used as the photocatalysts for H2 generation, the Meso-TiO2-25 delivers a high solar-driven H2 evolution rate under air mass 1.5 global (AM 1.5G) and visible-light (λ > 400 nm), respectively, which are significantly larger than that of commercial P25. This coordination-mediated self-assembly method paves a new way toward the design and synthesis of high performance mesoporous photocatalysts.
关键词： water splitting,mesoporous TiO2,phase junctions,self-assembly,photocatalysis
更新于2025-09-09 09:28:46