Browse
Submit Data
Databases
API
Help

Dataset Information

20 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Synthesis and Characterization of Anatase TiO₂ Microspheres Self-Assembled by Ultrathin Nanosheets.

ABSTRACT: In this paper, we report a novel anCd simple method for synthesizing the microspheres self-assembled from ultrathin anatase TiO₂ nanosheets with a high percentage of (001) facets via the hydrolysis process of the single-reagent (potassium fluorotitanate). We then used optical microscopy, scanning electron microscopy, and high-resolution confocal laser Raman spectroscopy to characterize the microspheres generated under different conditions. The study found that the size of the anatase TiO₂ microspheres synthesized was 0.5-3 μm. As the synthesis time increased, the corroded surface of the microspheres gradually increased, resulting in the gradual disappearance of the edges and corners of the anatase nanosheets. The exposure percentage of the (001) facets of ultrathin anatase nanosheets synthesized for 2 h at 180-200 °C are close to 100%. The microsphere whose surface is completely covered by these anatase nanosheets also has nearly 100% exposed (001) facets. This new anatase nanosheet-based self-assembled microsphere will have great application potential in pollution prevention, environmental protection, and energy fields.

SUBMITTER: Di J

PROVIDER: S-EPMC8198224 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Ultrathin self-assembled fibrin sheets.

Project description:Fibrin polymerizes into the fibrous network that is the major structural component of blood clots and thrombi. We demonstrate that fibrin from three different species can also spontaneously polymerize into extensive, molecularly thin, 2D sheets. Sheet assembly occurs in physiologic buffers on both hydrophobic and hydrophilic surfaces, but is routinely observed only when polymerized using very low concentrations of fibrinogen and thrombin. Sheets may have been missed in previous studies because they may be very short-lived at higher concentrations of fibrinogen and thrombin, and their thinness makes them very difficult to detect. We were able to distinguish fluorescently labeled fibrin sheets by polymerizing fibrin onto micro-patterned structured surfaces that suspended polymers 10 microm above and parallel to the cover-glass surface. We used a combined fluorescence/atomic force microscope system to determine that sheets were approximately 5 nm thick, flat, elastic and mechanically continuous. Video microscopy of assembling sheets showed that they could polymerize across 25-microm channels at hundreds of microm(2)/sec (approximately 10(13) subunits/s x M), an apparent rate constant many times greater than those of other protein polymers. Structural transitions from sheets to fibers were observed by fluorescence, transmission, and scanning electron microscopy. Sheets appeared to fold and roll up into larger fibers, and also to develop oval holes to form fiber networks that were "pre-attached" to the substrate and other fibers. We propose a model of fiber formation from sheets and compare it with current models of end-wise polymerization from protofibrils. Sheets could be an unanticipated factor in clot formation and adhesion in vivo, and are a unique material in their own right.

| S-EPMC2614779 | biostudies-literature

Self-assembly of mesoporous nanotubes assembled from interwoven ultrathin birnessite-type MnO2 nanosheets for asymmetric supercapacitors.

Project description:Porous nanotubes comprised of MnO2 nanosheets were fabricated with a one-pot hydrothermal method using polycarbonate membrane as the template. The diameter and thickness of nanotubes can be controlled by choice of the membrane pore size and the chemistry. The porous MnO2 nanotubes were used as a supercapacitor electrode. The specific capacitance in a three-electrode system was 365 F g(-1) at a current density of 0.25 A g(-1) with capacitance retention of 90.4% after 3000 cycles. An asymmetric supercapacitor with porous MnO2 nanotubes as the positive electrode and activated graphene as the negative electrode yielded an energy density of 22.5 Wh kg(-1) and a maximum power density of 146.2 kW kg(-1); these values exceeded those reported for other MnO2 nanostructures. The supercapacitor performance was correlated with the hierarchical structure of the porous MnO2 nanotubes.

| S-EPMC3902441 | biostudies-other

Self-hydrogenated shell promoting photocatalytic H2 evolution on anatase TiO2.

Project description:As one of the most important photocatalysts, TiO2 has triggered broad interest and intensive studies for decades. Observation of the interfacial reactions between water and TiO2 at microscopic scale can provide key insight into the mechanisms of photocatalytic processes. Currently, experimental methodologies for characterizing photocatalytic reactions of anatase TiO2 are mostly confined to water vapor or single molecule chemistry. Here, we investigate the photocatalytic reaction of anatase TiO2 nanoparticles in water using liquid environmental transmission electron microscopy. A self-hydrogenated shell is observed on the TiO2 surface before the generation of hydrogen bubbles. First-principles calculations suggest that this shell is formed through subsurface diffusion of photo-reduced water protons generated at the aqueous TiO2 interface, which promotes photocatalytic hydrogen evolution by reducing the activation barrier for H2 (H-H bond) formation. Experiments confirm that the self-hydrogenated shell contains reduced titanium ions, and its thickness can increase to several nanometers with increasing UV illuminance.

| S-EPMC6048119 | biostudies-literature

Radially oriented mesoporous TiO2 microspheres with single-crystal-like anatase walls for high-efficiency optoelectronic devices.

Project description:Highly crystalline mesoporous materials with oriented configurations are in demand for high-performance energy conversion devices. We report a simple evaporation-driven oriented assembly method to synthesize three-dimensional open mesoporous TiO2 microspheres with a diameter of ~800 nm, well-controlled radially oriented hexagonal mesochannels, and crystalline anatase walls. The mesoporous TiO2 spheres have a large accessible surface area (112 m(2)/g), a large pore volume (0.164 cm(3)/g), and highly single-crystal-like anatase walls with dominant (101) exposed facets, making them ideal for conducting mesoscopic photoanode films. Dye-sensitized solar cells (DSSCs) based on the mesoporous TiO2 microspheres and commercial dye N719 have a photoelectric conversion efficiency of up to 12.1%. This evaporation-driven approach can create opportunities for tailoring the orientation of inorganic building blocks in the assembly of various mesoporous materials.

| S-EPMC4640639 | biostudies-literature

Self-induced synthesis of phase-junction TiO2 with a tailored rutile to anatase ratio below phase transition temperature.

Project description:The surface phase junction of nanocrystalline TiO2 plays an essential role in governing its photocatalytic activity. Thus, facile and simple methods for preparing phase-junction TiO2 photocatalysts are highly desired. In this work, we show that phase-junction TiO2 is directly synthesized from Ti foil by using a simple calcination method with hydrothermal solution as the precursor below the phase transition temperature. Moreover, the ratio of rutile to anatase in the TiO2 samples could be readily tuned by changing the ratio of weight of Ti foil to HCl, which is used as the hydrothermal precursor, as confirmed by the X-ray diffraction analysis. In the photocatalytic reaction by the TiO2 nanocomposite, a synergistic effect between the two phases within a certain range of the ratio is clearly observed. The results suggest that an appropriate ratio of anatase to rutile in the TiO2 nanocomposite can create more efficient solid-solid interfaces upon calcination, thereby facilitating interparticle charge transfer in the photocatalysis.

| S-EPMC4750061 | biostudies-literature

Self-Templated Synthesis of Ultrathin Nanosheets Constructed TiO<sub>2</sub> Hollow Spheres with High Electrochemical Properties.

Project description:TiO2 is well-known nanomaterials and mostly used as solid nanoparticles, and normal hollow spheres for photocatalysts or electrode materials. In this study, a novel self-templated method is presented to successfully fabricate high-surface-area ultrathin nanosheets constructed TiO2 hollow spheres through the solvothermal treatment of the titanate-silicone composite particles combined with calcination. The uniquely structured hollow spheres exhibit excellent rate capability and good cycle stability even at a high current density of ≈10 C for the anode material of Li-ion battery.

| S-EPMC5102664 | biostudies-literature

Well-defined BiOCl colloidal ultrathin nanosheets: synthesis, characterization, and application in photocatalytic aerobic oxidation of secondary amines.

Project description:We demonstrate the first colloidal synthesis of single-crystalline BiOCl ultrathin nanosheets (UTNSs) that feature a well-defined square morphology. Unlike BiOCl nanomaterials prepared by hydrothermal routes, our colloidal BiOCl UTNSs exhibit hydrophobic surface properties and high activity and selectivity toward the photocatalytic aerobic oxidation of secondary amines to corresponding imines at room temperature. Hence, the application of BiOCl nanomaterials has been successfully extended from the widely studied photodecomposition of pollutants in aqueous solution to the synthesis of fine chemicals in organic solvent using a green approach.

| S-EPMC5649566 | biostudies-literature

Anatase TiO2 ultrathin nanobelts derived from room-temperature-synthesized titanates for fast and safe lithium storage.

Project description:Lithium-ion batteries (LIBs) are promising energy storage devices for portable electronics, electric vehicles, and power-grid applications. It is highly desirable yet challenging to develop a simple and scalable method for constructions of sustainable materials for fast and safe LIBs. Herein, we exploit a novel and scalable route to synthesize ultrathin nanobelts of anatase TiO2, which is resource abundant and is eligible for safe anodes in LIBs. The achieved ultrathin nanobelts demonstrate outstanding performances for lithium storage because of the unique nanoarchitecture and appropriate composition. Unlike conventional alkali-hydrothermal approaches to hydrogen titanates, the present room temperature alkaline-free wet chemistry strategy guarantees the ultrathin thickness for the resultant titanate nanobelts. The anatase TiO2 ultrathin nanobelts were achieved simply by a subsequent calcination in air. The synthesis route is convenient for metal decoration and also for fabricating thin films of one/three dimensional arrays on various substrates at low temperatures, in absence of any seed layers.

| S-EPMC4488874 | biostudies-other

Colloidal Synthesis of NbS<sub>2</sub> Nanosheets: From Large-Area Ultrathin Nanosheets to Hierarchical Structures.

Project description:Layered NbS2, a member of group-V transition metal dichalcogenides, was synthesized via a colloidal synthesis method and employed as a negative material for a supercapacitor. The morphologies of NbS2 can be tuned from ultrathin nanosheets to hierarchical structures through dynamics controls based on growth mechanisms. Electrochemical energy storage measurements present that the ultrathin NbS2 electrode exhibits the highest rate capability due to having the largest electrochemical surface area and its efficient ion diffusion. Meanwhile, the hierarchical NbS2 shows the highest specific capacitance at low current densities for small charge transfer resistance, displays 221.4 F g-1 at 1 A g-1 and 117.1 F g-1 at 10 A g-1, and cycling stability with 78.9% of the initial specific capacitance after 10,000 cycles. The aggregate or stacking of nanosheets can be suppressed effectively by constructing hierarchical structure NbS2 nanosheets.

| S-EPMC7154151 | biostudies-literature

Performance Enhancement of CdS/CdSe Quantum Dot-Sensitized Solar Cells with (001)-Oriented Anatase TiO2 Nanosheets Photoanode.

Project description:CdS/CdSe quantum dot-sensitized solar cells (QDSSCs) were fabricated on two types of TiO2 photoanodes, namely nanosheets (NSs) and nanoparticles. The TiO2 NSs with high (001)-exposed facets were prepared via a hydrothermal method, while the TiO2 nanoparticles used the commercial Degussa P-25. It was found that the pore size, specific surface area, porosity, and electron transport properties of TiO2 NSs were generally superior to those of P-25. As a result, the TiO2 NS-based CdS/CdSe QDSSC has exhibited a power conversion efficiency of 4.42%, which corresponds to a 54% improvement in comparison with the P-25-based reference cell. This study provides an effective photoanode design using nanostructure approach to improve the performance of TiO2-based QDSSCs.

| S-EPMC6329687 | biostudies-other