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Effective synthesis of nanoscale anatase TiO <sub/>2</sub> single crystals using activated carbon template to enhance the photodegradation of crystal violet
摘要： Nanoscale anatase TiO2 single crystals were successfully synthesized using three kinds of activated carbon (AC) templates through a simple sol–gel method. The optimal photocatalyst (T‐WOAC) was obtained using wood‐based AC template. X‐ray diffraction, transmission electron microscopy and Brunauer–Emmett–Teller analyses revealed that T‐WOAC possessed a small crystallite size of 8.7 nm and a clear mesoporous structure. The photocatalytic properties of samples were then evaluated through photodegradation of crystal violet (CV). Results implied that the photocatalysts prepared using the AC templates exhibited superior photocatalytic activity to that of the original TiO2. This enhancement may be due to the small crystallite size, large specific surface area and pore volume of the catalysts prepared with ACs. T‐WOAC showed high photocatalytic activity, CV degradation of 99.01% after 120 min of irradiation and k = 0.03914 min?1, which is 3.9 times higher than that of the original TiO2 (k = 0.00994 min?1). This result can be mainly attributed to the application of WOAC with moderate specific surface area and pore volume to produce T‐WOAC. Alkaline conditions benefitted the photodegradation of CV over photocatalysts. This work proposes a possible degradation mechanism of CV and indicates that the fabricated photocatalysts can be used to effectively remove CV from aqueous solutions.
关键词： photocatalyst,anatase TiO2 single crystals,sol–gel,crystal violet,activated carbon
更新于2025-11-14 17:04:02
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Photocatalytic Degradation of Bisphenol A Induced by Dense Nanocavities Inside Aligned 2D-TiO2 Nanostructures
摘要： The preparation of materials with aligned porosity in the nanometer range is of technological importance for a wide range of applications in molecular filtration, biomaterials and catalysis. Herein we present the advantages offered by cryo – lyophilisation technique as a smart and green non-standard concept to produce dense regular polyhedral nanocavities inside the 2D TiO2 nanosheets. Hierarchical morphologies of nanocavities start to appear at temperature higher than 800 °C and are strongly influenced by polymorph TiO2 evolution competing reactions. The small angle X-ray scattering (SAXS) analysis confirms self-assembled 3D nanocavities with size range from 5 to 10 nm in both length and width, and depth ~ 3.6 nm formed after realising of the confined ice-water. It was found that nanocavities enhance significantly the absorption properties of TiO2 in the UV region, thereby providing a new approach to increase the photoreactivity of 2D TiO2 nanosheets. The annealed precursors containing aqueous solution of peroxo polytitanic acid (PPTA) at 800 °C exhibited the highest photoactivity in degrading bisphenol A (BPA) due to evenly distributed nanocavities inside single anatase TiO2 nanocrystals interconnected and aligned onto the 2D TiO2 nanosheet arrays.
关键词： emerging pollutants,nanoconfined water,photocatalysis,nanocavities,freeze-drying,anatase TiO2
更新于2025-09-23 15:23:52
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EFFECT OF VOLTAGE ON TIO2 NANOTUBES FORMATION IN ETHYLENE GLYCOL SOLUTION
摘要： Anodization of Ti foils in ethylene glycol (EG) containing ammonium fluoride (NH4F), and hydrogen peroxide (H2O2) was carried out to study the effect of voltage on the formation of TiO2 nanotubes. The crystalline phase of the TiO2 nanotubes without further heat treatment were studied. The TiO2 nanotube arrays were produced by anodization of Ti foil at three different voltage; 10, 40, and 60 V in a bath with electrolytes composed of ethylene glycol (EG), ammonium fluoride (NH4F), and hydrogen peroxide (H2O2). The H2O2 is a strong oxidizing agent which was used as oxygen provider to increase the oxidation rate for synthesizing highly ordered and smooth TiO2 nanotubes. Anodization at voltage greater than 10 V leads to the formation of tubular structure where higher anodization voltage (~ 60 V) yield to larger tube diameter (~ 180 nm). Crystallinity of the nanotubes is improved as the voltage was increased. The transformation of amorphous to anatase can be obtained for as anodized TiO2 without any heat treatment. The Raman spectra results show the anodization at 40 V and 60 V gives anatase peak in which confirms the crystalline phase. The stabilization of the crystalline phase is due to the oxygen vacancies and ionic mobilities during the anodization at high voltage.
关键词： anatase,TiO2 nanotubes,crystallization,anodization
更新于2025-09-23 15:23:52
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Hierarchical rutile/anatase TiO2 nanorod/nanoflower thin film: Synthesis and characterizations
摘要： Hierarchical TiO2 nanorod/nano?ower thin ?lm was synthesized on ?uorine doped tin oxide glass via hydrothermal and aqueous chemistry methods. According to ?eld emission scanning electron microscopy results, the thin ?lm was crack-free and uniform. Primary nanorods had an average diameter of 95 nm and a length of 2 μm. They were perpendicular to the substrate owing to the TiO2 prenucleation. Growth of the nano?owers on the nanorods could increase both the speci?c surface area and roughness. X-ray di?raction and Raman spectroscopy showed that the nanorods were rutile; while the nano?owers were anatase. E?cient electron transfer from anatase to rutile could therefore occur. According to the di?use transmittance spectroscopy examination, the light harvesting rate was ameliorated and the band gap energy reduced to 2.83 eV. This was attributed to the F-doping the sample during synthesis. The enhancement of the photoelectrochemical activity allowed substitution of the TiO2 nanorod/nano?ower thin ?lm for the traditional TiO2 nanorods usually used in solar cells, sensors, and photocatalytic systems.
关键词： Aqueous chemistry,Nanorod array,Rutile/anatase TiO2,Hydrothermal,Nano?ower
更新于2025-09-23 15:22:29
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Effects of carbon doping and vacancy defect on the magnetism of anatase TiO2
摘要： The magnetism origin and mechanism of anatase TiO2 with C doping and vacancy remain controversial. In this study, the effects of C doping and vacancy defect on the magnetism of TiO2 were investigated by generalized gradient approximation and Hubbard U method based on density functional theory. Systems with coexisting interstitial C and O vacancies achieved half-metallic ferromagnetism, and the Curie temperature was above the room temperature. The system used as electron injection source reached 100% electron spin polarization. The Ti32CO2O62 system exhibited ferromagnetism, and the Curie temperature was above the room temperature. The magnetism source of Ti16CiO31 and Ti32CO2O62 demonstrated strong hybrid coupling electron exchange effects among Ti-3d, O-2p, and C-2p orbits which is consistent with the RKKY model of d-p orbital electron exchange.
关键词： Carbon doping and vacancy defect,Magnetism,Anatase TiO2,First-principles
更新于2025-09-23 15:21:21
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Effect of DI Water Content on the Growth of Anatase TiO<sub>2</sub> Nanotubes Synthesized by Anodization Process
摘要： Vertically aligned anatase TiO2 nanotubes (NTs) were fabricated by anodization of a pure Ti foil in ethylene glycol solutions containing different concentrations of deionized (DI) water. The morphology, elemental composition, and crystallization of TiO2 nanostructures were analyzed by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray spectroscopy (XPS), respectively. The diameter and length of TiO2 NTs were controlled by varying concentrations of DI water. Furthermore, we found that TiO2 NTs in DI water 12 wt. % was suitable for further applications in UV photodetector due to it has a high volume to surface area ratio and long tube. TiO2 NTs have a high potential in various applications such as UV photodetectors, gas sensor, dye sensitized solar cells, and photocatalysts.
关键词： Anatase TiO2,Anodization,Thermal annealing,Titanium dioxide,Nanotubes
更新于2025-09-23 15:21:01
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Enhanced current density of anatase TiO2 nanowire arrays by interface connection modulation in flexible quantum dot sensitized solar cells
摘要： The stability and photovoltaic conversion efficiency are very important issues for the industry application of flexible solar cells, which have been seriously limited by the interface connection of basic photo-electrodes in solar cells. Here, one-dimensional TiO2 nanowire arrays films were employed as photo-electrodes of flexible solar cells, which have modulated interface connection of the photo-electrodes by introducing small size of nanoparticles and heating pressure process. The charge generation and separation properties of photo-electrodes have been influenced, which may be attributed by the changes on band energy of small size of nanoparticles in photo-electrodes. With the improvement on the interface connection in the photo-electrodes, the charge transfer property has been effectively improved, which have exhibited a higher current density value of the solar cells, achieving photovoltaic conversion efficiency enhancement from 2.55% to 3.90%. Moreover, there have no obvious changes on the photovoltaic conversion efficiency of these flexible QDSSCs solar cells under the curling condition.
关键词： Anatase TiO2 nanowire arrays,Flexible quantum dot sensitized solar cell,Interface connection,Photovoltaic performance enhancement,Small size of nanoparticles,Heating pressure
更新于2025-09-23 15:19:57
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High-Efficiency Perovskite Solar Cells Enabled by Anatase TiO2 Nanopyramid Arrays with Oriented Electric Field
摘要： One-dimensional (1D) nanostructured oxides have been proposed as excellent electron transport materials (ETMs) for perovskite solar cells (PSCs), but this has not yet been demonstrated experimentally. Here, we exploit a facile hydrothermal approach to grow highly oriented anatase TiO2 nanopyramid arrays and further demonstrate their advantages for application in PSCs. The oriented TiO2 nanopyramid arrays afford sufficient contact area for electron extraction and increase light transmission. Moreover, the nanopyramid array/perovskite system exhibits an oriented electric field that can increase charge separation and accelerate charge transport, thereby suppressing charge recombination. As a result, the anatase TiO2 nanopyramid arrays-PSCs deliver a champion power conversion efficiency of ~22.5%, which is the highest PCE reported thus far for PSCs consisting of 1D ETMs. This work demonstrates that the rational design of 1D ETMs can achieve PSCs that perform as well as typical mesoscopic and planar PSCs.
关键词： Anatase TiO2,Electric field distribution,Perovskite solar cells,One-dimensional nanostructures,Nanopyramid arrays
更新于2025-09-23 15:19:57
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Synthesis and photocatalytic properties of electrodeposited bismuth oxyiodide on rutile/anatase TiO<sub>2</sub> heterostructure
摘要： Bismuth oxyiodide (BiOI) modified rutile/anatase TiO2 heterostructure was fabricated by a three-step process. Anatase TiO2 sheet was first formed on fluorine-doped tin oxide (FTO) glass substrate. Rutile TiO2 nanorods were then grown on anatase TiO2 sheet via a hydrothermal process. BiOI was finally coated on the surface of hierarchical TiO2 film using an electrochemical deposition method. Photocatalytic tests on degradation of methylene blue (MB) in water indicated that BiOI modified hierarchical TiO2 film possessed an excellent photocatalytic activity superior to those of the monophase anatase and rutile TiO2 films, commercial P25 film and hierarchical TiO2 film. The enhanced photocatalytic performance was probably attributed to the synergetic effects of strong visible light absorption and formation of heterojunctions by the interfaces in the BiOI / rutile TiO2 / anatase TiO2 / FTO structure, which promoted efficient separation of photoinduced electron-hole pairs. In addition, the main active species during the degradation were confirmed to be hydroxyl radicals and superoxide radicals.
关键词： hierarchical rutile/anatase TiO2,nanostructure,film,electrodeposition,charge carrier separation,visible absorption,BiOI
更新于2025-09-19 17:15:36
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Supercritical CO <sub/>2</sub> -assisted deposition of NiO on (101)-anatase-TiO <sub/>2</sub> for efficient facet engineered photocatalysts
摘要： NiO/(101)-anatase-TiO2 heterostructure nanoparticles were synthesized by depositing NiO onto the (101) facet of anatase crystals via the supercritical fluid chemical deposition (SFCD) route. Thorough characterization experiments performed by various techniques (XRD, UV-Vis DRS, N2 sorption, HR-TEM, EDX, and XPS) indicate that the SFCD method allowed a good dispersion of NiO onto the TiO2 nanoparticles for NiO amounts below 2 wt%. Compared to pure TiO2, the 0.1–1 wt% NiO–TiO2 nanocomposites showed enhanced photocatalytic properties for methylene blue (MB) and methyl orange (MO) decomposition under UV light irradiation, the 0.25 wt% NiO–TiO2 system leading to the highest efficiencies. The photocatalytic properties were then rationalized in terms of the acidic properties and electronic structures of the NiO–TiO2 nanocomposites. This higher photocatalytic activity was mainly related to the heterocontact at the interface of the NiO–TiO2 crystallites and to the enhanced reaction rates at the NiOx surface.
关键词： anatase-TiO2,Supercritical CO2,photocatalysis,NiO deposition,facet engineering
更新于2025-09-19 17:15:36