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Voids in walls of mesoporous TiO2 anatase nanotubes by controlled formation and annihilation of protonated titanium vacancies
摘要： Amorphous TiO2 nanotubes (TNTs) grown anodically on Ti metal in aqueous electrolytes show a crystallization behaviour strongly dependent on the atmosphere used during annealing at high temperature. In wet oxidizing conditions, the amorphous TNTs walls transform into relatively large and well crystallized anatase-like domains permeated by prismatic voids. On the other hand, crystallization of the amorphous nanotubes under dry reducing conditions induces nanocrystalline aggregates that do not show prismatic voids and exhibit different electronic properties. Supported by density functional theory calculations, it is argued that the formation or absence of voids can be understood in terms of formation and condensation of protonated titanium vacancies. Tunable morphology through defect chemical engineering as such, enables TNTs with increased surface area and catalytic activity, which find potential application in supercapacitors, sensors, photocatalysis, photoelectrochemistry, and dye-sensitized solar cells.
关键词： TiO2 nanotube voids,Titanium oxohydroxide,Supercapacitors,Black titania,Anatase
更新于2025-09-12 10:27:22
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[IEEE TENCON 2019 - 2019 IEEE Region 10 Conference (TENCON) - Kochi, India (2019.10.17-2019.10.20)] TENCON 2019 - 2019 IEEE Region 10 Conference (TENCON) - Investigation of “Keriang” fruit Dye application on the performance of Dye-Sensitized solar cell with anatase-rutile TiO <sub/>2</sub> Electrode
摘要： Dye-sensitized solar cell (DSSC) or ‘Gratzel cell’ is a low-cost solar cell from the thin film family which consists of TiO2 electrode coating, sensitizer from dye molecules soaked in the TiO2 film, a mediator electrolyte layer, and a counter electrode. This paper focuses on fabricating dye-sensitized solar cell (DSSC) with anatase and anatase-rutile mixture of nanocrystalline TiO2 at varied thickness sensitized with high light-absorbing nature dye and an alternative conductive counter electrode catalytic material. This paper proposes on the potentials of 10 μm thickness of rutile-anatase (RA) with a 1:4 ratio concentration, absorbed into a high concentration anthocyanin from ‘keriang’ fruit extract and by the use of carbon as a counter electrode. This arrangement shows the highest solar cell efficiency at 1.16% with higher short circuit current of 5.5 mA/cm2 and fill factor of 0.55 which is the highest among overall experimented nature-based solar cell.
关键词： Keriang,Rutile,Anatase,TiO2,Dye,DSSC,Dye-Sensitized solar cell
更新于2025-09-12 10:27:22
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Microwave-Assisted Synthesis of High-Energy Faceted TiO2 Nanocrystals Derived from Exfoliated Porous Metatitanic Acid Nanosheets with Improved Photocatalytic and Photovoltaic Performance
摘要： A facile one-pot microwave-assisted hydrothermal synthesis of rutile TiO2 quadrangular prisms with dominant {110} facets, anatase TiO2 nanorods and square nanoprisms with co-exposed {101}/[111] facets, anatase TiO2 nanorhombuses with co-exposed {101}/{010} facets, and anatase TiO2 nanospindles with dominant {010} facets were reported through the use of exfoliated porous metatitanic acid nanosheets as a precursor. The nanostructures and the formation reaction mechanism of the obtained rutile and anatase TiO2 nanocrystals from the delaminated nanosheets were investigated. The transformation from the exfoliated metatitanic nanosheets with distorted hexagonal cavities to TiO2 nanocrystals involved a dissolution reaction of the nanosheets, nucleation of the primary [TiO6]8? monomers, and the growth of rutile-type and anatase-type TiO2 nuclei during the microwave-assisted hydrothermal reaction. In addition, the photocatalytic activities of the as-prepared anatase nanocrystals were evaluated through the photocatalytic degradation of typical carcinogenic and mutagenic methyl orange (MO) under UV-light irradiation at a normal temperature and pressure. Furthermore, the dye-sensitized solar cell (DSSC) performance of the synthesized anatase TiO2 nanocrystals with various morphologies and crystal facets was also characterized. The {101}/[111]-faceted pH2.5-T175 nanocrystal showed the highest photocatalytic and photovoltaic performance compared to the other TiO2 samples, which could be attributed mainly to its minimum particle size and maximum specific surface area.
关键词： high-energy facets,photocatalytic activity,photovoltaic performance,anatase TiO2 nanocrystals
更新于2025-09-11 14:15:04
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Laser‐Assisted, Large‐Area Selective Crystallization and Patterning of Titanium Dioxide Polymorphs
摘要： While ubiquitous in multiple industrial applications, the widespread use of solution-based precursors for crystalline titanium dioxide (TiO2) for optoelectronic device integration remains limited due to its high processing temperature. This limitation generates material compatibility issues and complicates the fabrication steps, especially for low-temperature substrates used in flexible hybrid electronics and low-cost photovoltaics. It is currently possible to crystallize TiO2 at lower processing temperatures, but it requires a carefully-controlled atmosphere or metallic doping of the amorphous precursor and can only achieve a low-yield conversion of the precursor. This paper presents a qualitative method for the processing of an amorphous photo-sensitive precursor in order to achieve high-yield conversion to highly-crystalline TiO2 at room-temperature and in ambient environment without added dopants using a low-energy laser. Moreover, it demonstrates the ability to controllably convert locally to anatase or rutile TiO2 only by adjusting the laser power density. This work shows real potential for the additive manufacturing of TiO2 structures for photo-catalysis, printable flexible hybrid electronics and low-cost photovoltaics using low-energy laser processing that is compatible with heat sensitive materials and flexible substrates.
关键词： rutile,anatase,titanium dioxide,laser-assisted conversion
更新于2025-09-11 14:15:04
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Water Dissociation and Hydroxyl Ordering on Anatase
摘要： We studied the interaction of water with the anatase TiO2e001T surface by means of scanning tunneling microscopy, x-ray photoelectron spectroscopy, and density functional theory calculations. Water adsorbs dissociatively on the ridges of a (1 × 4) reconstructed surface, resulting in a (3 × 4) periodic structure of hydroxyl pairs. We observed this process at 120 K, and the created hydroxyls desorb from the surface by recombination to water, which occurs below 300 K. Our calculations reveal the water dissociation mechanism and uncover a very pronounced dependence on the coverage. This strong coverage dependence is explained through water-induced reconstruction on anatase TiO2e001T-e1 × 4T. The high intrinsic reactivity of the anatase TiO2e001T surface towards water observed here is fundamentally different from that seen on other surfaces of titania and may explain its high catalytic activity in heterogeneous catalysis and photocatalysis.
关键词： x-ray photoelectron spectroscopy,scanning tunneling microscopy,anatase TiO2,hydroxyl ordering,density functional theory,water dissociation
更新于2025-09-10 09:29:36
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Highly efficient solar light-assisted TiO2 nanocrystalline for photodegradation of ibuprofen drug
摘要： Pure anatase, pure brookite, and anatase/brookite heterojunction (ABH) TiO2 with tunable anatase/brookite ratios were prepared via a facile hydrothermal process using Titanium (III) sulfate, as precursor and different glycine/NaOH ratios, as pH adjusting reagents. The obtained samples were characterized by XRD, Raman, FT-IR, FE-SEM, TEM, EDX, BET surface area, UV-vis-DRS, XPS, and PL. The photocatalytic performance of as-synthesized catalysts was evaluated by photodegradation of ibuprofen under simulated solar light. The photodegradation rate of A/B heterojunction TiO2 photocatalysts was greater 12.5, 8.5 and 1.6 times than that the pure brookite, pure anatase, and the commercial P-25, respectively. The complete ibuprofen mineralization (100%) was performed under simulated solar light within 5 h using the photocatalyst obtained at pH 10 (i.e. 1:3 glycine/NaOH volume ratio), however, the commercial P-25 is 75%. The optimum sample containing 61.8%A/38.2%B exhibits the best photocatalytic activity due to it has a mesoporous structure, high surface area, and the low PL intensity.
关键词： Ibuprofen,Solar light,Photodegradation,Anatase-brookiteTiO2,Photocatalyst
更新于2025-09-10 09:29:36
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Microwave Assisted Synthesis, Modification With Platinum And Photocatalytical Properties of TiO2 Nanofibers
摘要： In the present work formation of active TiO2 nanoparticles in microwave synthesis and their modification with platinum were studied. Anatase nanopowder and 10 M KOH solution were used as raw materials. Microwave assisted synthesis method permited to obtain TiO2 nanofibres and nanowires with a diameter of 10 nm and a specific surface area in the range of 70 – 150 m2/g. In order to modify TiO2 nanofibers with platinum it was stirred in H2PtCl6 solution under UV irradiation. Photocatalytic activity was determined by degradation of the methylene blue (MB) solution under UV and visible light irradiation. The obtained samples showed higher photocatalytic activity with respect to pure TiO2 nanofibers. The doped TiO2 nanofibers were appropriate for degradation of harmful organic compounds as well as for hydrogen production by water splitting.
关键词： platinum,nanowires,titania nanofibers,anatase,photocatalysis
更新于2025-09-10 09:29:36
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DFT Calculation about Oxygen Vacancy to Promote Adsorption of a CO Molecule on Single Au-Supported Titanium Dioxide
摘要： The properties and behavior of a single Au atom supported anatase TiO2(001) surface are calculated using density functional theory (DFT) methods. The structures and energies of adsorbed single Au on an anatase TiO2(001) surface with surface oxygen vacancy, as well as subsurface oxygen vacancy, are systematically determined. Initially, the surface threefold coordinated oxygen vacancy adjacent to a single Au atom, rather than the surface two-fold coordinated oxygen vacancy and subsurface threefold coordinated oxygen vacancy, results in more stability for anatase TiO2(001) surface with an Au adatom. Afterwards, the CO molecule is more strongly adsorbed on the single Au-supported TiO2(001) surface with surface threefold coordinated oxygen vacancy when comparing to other structures. This is attributed to the more negatively charged Au single-atom caused by a surface threefold coordinated oxygen vacancy presents concededly active for CO adsorption.
关键词： surface,anatase TiO2,adsorption,oxygen vacancy,Au,CO molecule
更新于2025-09-10 09:29:36
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A crystallization method for preparation of anatase-based glass-ceramic glaze
摘要： Developing a way to prepare effective, durable and high-temperature stable anatase-based photocatalytic ceramic is of great significance. In this work, we report a crystallization method for the preparation of anatase-based glass-ceramic glaze. The raw materials were made into frit and glazed on ceramic bodies. The glazed ceramics were sintered at 1180oC and soaked at 700oC. The effect of soaking temperature on the crystallization process was investigated. The photocatalytic property of the glazed tiles was evaluated by degradation of methyl orange. Experimental results show that after sintering and soaking at 700 oC, nanosized anatase grains crystallize in glaze. The crystallization of anatase nanograins is attributed to the relative high viscosity at crystallization temperature. HF etching makes more anatase grains exposed on the surface. The sample etched for 45 seconds shows the highest photocatalytic activity and the methyl orange is decomposed by about 90% after illumination for 35 h.
关键词： Glass-ceramic glaze,Photocatalytic property,Anatase,Crystallization process
更新于2025-09-10 09:29:36
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Light-Tuned DC Conductance of Anatase TiO2 Nanotubular Arrays: Features of Long-Range Charge Transport
摘要： Experimental results related to the photoactivated dc conductance of anatase TiO2 nanotubular arrays (aTNTAs) under pulsed irradiation by a laser light inside and outside the fundamental absorption band are presented. It is found that the mobility and diffusion coefficients of charge carriers in the examined aTNTA are extremely low due to a strong charge-phonon coupling, abundance of shallow traps, and hopping conductivity between adjacent nanotubes. We consider that the confining electric field appeared within the array structure due to the difference in the local concentrations of excess electrons and holes at large values of the dc conductance suppresses the drift current. In this case, the dc conductance of such aTNTAs is mainly matured by the diffusion of mobile carriers. A recurrent kinetic model for evolution of the dc conductance of aTNTAs under laser irradiation has been proposed to interpret the experimental results.
关键词： anatase nanotubes,laser irradiation,dc conductance,Urbach energy,drift current,inter-band transition,diffusion current,charge mobility
更新于2025-09-10 09:29:36