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The Effects of the Content of NiO on the Microstructure and Photocatalytic Activity of the NiO/TiO2 Composite Film
摘要： The NiO/TiO2 composite films with the NiO content of 3 %, 5 %, 10 %, 13 %, 15 % and 20 % were prepared by mechanical coating technology and subsequent oxidation process. The composition and microstructure of the films were analyzed by X-ray Diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS). The photocatalytic activity was evaluated and the effects of the content of NiO on microstructure and photocatalytic activity of the films were studied. The results show that NiO particles are dispersed in the Ti coatings, and the NiO concentration in the inner layer of the coatings is higher than in the outer layer. With the addition of NiO in the NiO/Ti coating, the ductility is deteriorated and the thickness is reduced of the NiO/Ti coatings. The films with NiO/TiO2/Ti composite microstructure are obtained by the oxidation of NiO/Ti coatings. Photocatalytic efficiency of the films is obviously enhanced with the help of the p-n junction heterostructure in the NiO/TiO2 films. The optimum content of NiO is about 13 %, and the degradation rate of methyl orange solution reaches the maximum value of 88.44 %.
关键词： mechanical coating technology,NiO content,photocatalytic activity,NiO/TiO2 composite films
更新于2025-09-23 15:22:29
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Oxygen Vacancy Induced Structural Distortions in Black Titania - A Unique Approach using Soft X-Ray EXAFS at the O K-Edge
摘要： Unknown changes in the crystalline order of regular TiO2 result in the formation of black titania, which has garnered significant interest as a photocatalytic material due to the accompanying electronic changes. Herein, we determine the nature of the lattice distortion caused by an oxygen vacancy that in turn results in the formation of mid-band gap states found in previous studies of black titania. We introduce an innovative technique using a state-of-the-art silicon drift detector, which can be used in conjunction with extended x-ray absorption fine structure (EXAFS) to measure bulk interatomic distances. We illustrate how the energy dispersive nature of such a detector can allow us an unimpeded signal, indefinitely in energy space, thereby sidestepping the hurdles of more conventional EXAFS, which is often impeded by other absorption edges.
关键词： black titania,EXAFS,black TiO2,structural distortion,photocatalytic
更新于2025-09-23 15:22:29
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A novel bi-functional SiO2@TiO2/CDs nanocomposite with yolk-shell structure as both efficient SERS substrate and photocatalyst
摘要： A novel multi-functional yolk-shell SiO2@TiO2/CDs(y-STCs) nanocomposite with interesting structure of SiO2 cores, porous TiO2 shell, and cavities was synthesized by using a simple method. The experimental results indicate that the yolk-shell structure and modification of carbon dots (CDs) play important roles in the enhancement of SERS signals and photocatalytic performance. The y-STCs nanocomposite used as the SERS substrate showed excellent efficiency and reproducibility for the detection of rhodamine 6G (R6G). The detection limit of R6G was shown to be as low as 6 × 10?8 M. Furthermore, the fabricated y-STCs nanocomposite utilized as the photocatalytst for the degradation of dinitraphenols (DNP) can greatly shorten reaction time to 120 min compared with previous studies, and the DNP degradation rate could reach 96% under simulated sunlight irradiation. The y-STCs nanospheres also possessed excellent cycle stability for the photocatalytic degradation of DNP. Thus, the bi-functional y-STCs nanocomposite may have potential applications in the detection and photocatalytic degradation of organic pollutants.
关键词： SiO2@TiO2/CDs nanocomposite,Yolk-shell structure,SERS detection,Photocatalytic activity
更新于2025-09-23 15:22:29
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Different approaches for the solar photocatalytic removal of micro-contaminants from aqueous environment: Titania vs. hybrid magnetic iron oxides
摘要： This work reports on the light-induced heterogeneous photodegradation of four micro-contaminants (MCs): Carbamazepine (C), Flumequine (F), Ibuprofen (I), and Sulfamethoxazole (S), using two different heterogeneous advanced oxidation processes. The first one is the semiconductor photocatalysis, run in the presence of the suspension of a home prepared TiO2 (TiO2 HP); the second one is an heterogeneous photo-Fenton process run in the presence of a hybrid magnetic nanomaterial (MB3) with an iron oxides core and an organic shell made of bio-based substances (BBS) isolated from urban biowaste. The two materials work upon two different mechanisms and were already tested (and the action mechanism hypothesized) at the lab scale under model conditions: TiO2 acts as photocatalyst through the photo-generation of hole/electron pairs able to give rise to oxidation and reduction reactions, whereas hybrid magnetic nanomaterial acts in the presence of H2O2 by a photo-Fenton like mechanism. The results evidenced the better performances of TiO2 HP (also better than the well-known reference TiO2 P25). Preliminary photodegradation experiments carried out in a pilot plant under natural solar radiation confirmed the good results obtained with TiO2 HP. Moreover, in the adopted experimental conditions, the Fe(II) leached from MB3 can be considered as responsible of the MCs degradation through a homogeneous photo-Fenton reaction, where MB3 act as iron reservoir.
关键词： TiO2,Micro-contaminants,Photo-Fenton,Photocatalysis,Water treatments,Magnetic materials.
更新于2025-09-23 15:22:29
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Enhanced UV-light driven photocatalytic performances and recycling properties of TiO2/AlON composite photocatalyst
摘要： AlON has been reported to have photocatalytic capability under ultraviolet-light (UV-light), which can be improved by fabricating large-sized powder (~20 μm) having porous skeleton microstructure. To further enhance photocatalytic property of AlON, highly photocatalytic-efficient nanocrystalline TiO2 was loaded onto both the outer and inner surface of porous AlON particles by hydrothermal method. In order to ensure easy recovery without secondary pollution, the obtained composite powder was filtered in deionized water three times to remove both small-sized AlON and free TiO2 particles to produce a composite photocatalyst with particle size > 10 μm. The proposed TiO2/AlON showed excellent photocatalytic performance on Methylene blue (MB) and Methyl orange (MO) for 97.9% and 99.1% of pollutants (in 30 mg/L, 40 mL solution) being degraded by 50 mg as-synthesized composite photocatalyst in 120 min. Further test showed that the hydrothermal process can significantly improve the photocatalytic performance of TiO2/AlON composite photocatalyst and its enhancement mechanism were discussed. In addition, the large-sized composite photocatalyst is easy to recover and stable to reuse with no regeneration needed.
关键词： Hydrothermal method,Composite photocatalyst,TiO2/AlON,UV-light
更新于2025-09-23 15:22:29
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Efficient visible-light-responsive photocatalyst: Hybrid TiO2-Ag3PO4 nanorods
摘要： Herein, ordered TiO2-Ag3PO4 nanorods are fabricated by loading Ag3PO4 nanoparticles on the as-prepared brookite TiO2 nanorods. The amount of Ag3PO4 nanoparticles loaded on brookite TiO2 nanorods can be rationally optimized. These hybrid TiO2-Ag3PO4 nanorods could provide large surface area, extend the visible light absorption and facilitate the charge separation, leading to efficient visible-light-driven photocatalytic performance. When evaluated as photocatalysts under visible light illumination, all the hybrid TiO2-Ag3PO4 nanorods exhibit high photocatalytic activity for degrading 2-propanol. Particularly, TiO2-Ag3PO4-3 enables the best photocatalytic property, which yields high acetone production of 147 ppm at 3 h and CO2 production of 424 ppm at 11 h.
关键词： TiO2-Ag3PO4,Visible-light-responsive,Nanocomposites,Solar energy materials
更新于2025-09-23 15:22:29
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Chromium segregation in Cr-doped TiO2 (rutile): impact of oxygen activity
摘要： This work considers the effect of chromium surface segregation for polycrystalline Cr-doped TiO2 on surface vs. bulk defect disorder. It is shown that annealing of Cr-doped TiO2 (0.04 at% Cr) in the gas phase of variable oxygen activity at 1273 K results in a gradual transition in the valence of chromium at the surface from predominantly Cr3+ species in reduced conditions, p(O2) = 10?12 Pa, to comparable concentrations of both Cr3+ and Cr6+ species in oxidising conditions, p(O2) = 105 Pa. The reported data is considered in terms of defect equilibria leading to the formation of positively and negatively charged chromium in both the cation sub-lattice and interstitial sites. The derived theoretical models represent the effect of oxygen activity on the surface charge and the resulting electric field leading to migration mechanism of charged chromium species.
关键词： Oxygen activity,XPS,Cr-doped TiO2,Segregation,Titanium dioxide
更新于2025-09-23 15:22:29
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Interfacial Charge Transfer in 0D/2D Defect-Rich Heterostructures for Efficient Solar-Driven CO2 Reduction
摘要： Two-dimensional graphitic carbon nitride (g-C3N4) has been widely explored as a promising photocatalyst for solar CO2 conversion. However, rapid charge recombination and low visible-light utilization are severely detrimental to photocatalytic CO2 conversion. Zero-dimensional/two-dimensional (0D/2D) heterostructures are considered the promising materials with size tunability and enhanced charge separation efficiency for photocatalysis. Herein, a 0D/2D heterostructure of oxygen vacancy-rich TiO2 quantum dots confined in g-C3N4 nanosheets (TiO2-x/g-C3N4) was prepared by in-situ pyrolysis of NH2-MIL-125 (Ti) and melamine. Charge dynamics analysis by time-resolved photoluminescence (tr-PL) and femtosecond and nanosecond pump-probed transient absorption (TA) spectra revealed that charges transfer occured from 2D-g-C3N4 to 0D-TiO2 at an ultrafast subpicosecond time scale (<1 ps) through the intimate interface. The overall fast decay of the charge carriers was attributed to interfacial charge transfer, which was accompanied by recombination relaxation mediated by shallow trapped sites. Ultrafast interfacial charge transfer greatly promoted charge separation as well as electrons in shallow trapped sites were easily trapped by CO2. In addition, combing with the synergetic advantage of strong visible light absorption, high CO2 adsorption and large surface area, TiO2-x/g-C3N4 exhibited a superior CO evolution rate of 77.8 μmol g?1 h?1, roughly 5 times that of pristine g-C3N4 (15.1 μmol g?1 h?1). This work provides in-depth insights into optimizing the heterojunction for robust solar CO2 conversion.
关键词： TiO2 quantum dots,solar CO2 reduction,charge transfer,0D/2D heterostructures,oxygen vacancy
更新于2025-09-23 15:22:29
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Construction of Ag@AgCl decorated TiO2 nanorod array film with optimized photoelectrochemical and photocatalytic performance
摘要： A novel Ag@AgCl/TNR film photocatalyst was successfully obtained by a facile multistep route. Using a well-organized TiO2 nanorod array (TNR) film as the starting material, Ag nanoparticles were uniformly deposited on the TNR film via a photochemical reduction, and in situ oxidation of Ag by FeCl3 solution resulted in the formation of Ag@AgCl/TNR film. The structure, morphology, composition, optical, photocatalytic and photoelectrochemical properties of the obtained films were investigated in detail. The results showed that core-shell Ag@AgCl can effectively promote the transfer of photo-generated electron-hole pairs, suppress their recombination, and enhance the visible light absorption. The Ag@AgCl/TNR film with 60 min oxidation time (S60) showed the highest photocurrent and best transfer performance of interfacial electrons in the electrochemical impedance spectroscopy (EIS) Nyquist plots. For the photodegradation of methyl orange (MO), the S60 exhibited the highest photocatalytic efficiency (90.8%) and good stability under visible light irradiation, which can be comparable and even better than the previous reports. A detailed photocatalytic mechanism was proposed on the basis of the fact that Ag nanoparticles with surface plasma resonance (SPR) can be excited by visible light and this unique structure effectively transfers photo-generated electrons from Ag to TiO2 conduction band, accomplished by the transfer of compensative electrons from a donor (Cl-) to Ag nanoparticles.
关键词： Nanorod array,Photocatalytic activity,Photocurrent,TiO2,Ag@AgCl
更新于2025-09-23 15:22:29
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Photocatalytic Degradation of Aflatoxin B1 by activated carbon supported TiO2 catalyst
摘要： The photocatalytic efficiency of activated carbon supported TiO2 catalyst (AC/TiO2) for degradation of aflatoxin B1 (AFB1) under UV-Vis light was evaluated in this study. AC/TiO2 was prepared by simple hydrothermal synthesis and characterized by scanning electron micrograph (SEM), X-ray diffraction (XRD) and FT-IR. The various factors including catalyst dosage, pH value and light source affecting the degradation efficiency of AFB1 were also investigated. The higher degradation efficiency of AFB1 by AC/TiO2 composite (98 %) than bare TiO2 (76 %) were attributed to a higher surface area and enhanced visible light intensity by the synergy of AC and TiO2. The degradation process of AFB1 was fitted with the pseudo-first-order kinetic model. In addition, the catalyst can be easily separated from the solution and keep good activity. The hole (h+) and the hydroxyl radicals (?OH) were found to play an important role in the degradation of AFB1. These results demonstrated that AC/TiO2 possess synergy of high absorption capacity and photoactivity, thus supplying a simple, efficient and green approach for the degradation of AFB1.
关键词： AC/TiO2 catalyst,Photocatalytic Degradation,Aflatoxin B1
更新于2025-09-23 15:22:29