Dandelion-like TiO2 Research Articles

Application of green synthesized biogenic Nd2Zr2O7 supported on dendritic fibrous nano-titanium for photocatalytic and antibacterial activities

The combination of a phase junction and fibrous structure has been proven to improve the catalytic ability and performance, as well as the separation of nano titanium oxide. However, there is still a pressing need for facile and environmentally sustainable fabrication techniques. In this research, we introduce an innovative approachfor the fabrication of dandelion-like TiO2 with anatase/TiO2 phase interfaces and an extremely specific exterior layer using a user-friendly and green deep eutectic solvent-tuning method. We have successfully synthesized DaNd2Zr2O7 nanospheres on dendritic fibrous nanotitanium (DFNT@DaNd2Zr2O7) using a straightforward method. The DFNT@DaNd2Zr2O7 composite retained its mesoporous structure and crystalline morphology, despite the loading of DaNd2Zr2O7. These nanocomposites are employed as active photocatalysts under UV radiation and can effectively treat water contaminated with organic pollutants and microorganisms. Additionally, they exhibit antimicrobial properties against gram-positive species like pathogenic strains of Enterococcus faecalis and Staphylococcus aureus, as well as Gram-negative species like Escherichia coli, Furthermore and Klebsiella pneumonia, these nanocomposites exhibit excellent stability over ten cycles, reinforcing their potential as proficient catalysts to address environmental concerns.

Efficient and selective cycloaddition of carbon dioxide, amines, and alkenes using Gd2ZnMnO6/Zn2MnO4 supported on dendritic fibrous nano-titanium

The co-fabrication of a phase junction and fibrous structure has been demonstrated to enhance the catalytic ability, catalytic performance, and separation of nano titanium oxide. Nevertheless, despite these benefits, there remains a critical need for facile and environmentally sustainable fabrication methods. In this study, we present an innovative approach to synthesizing dandelion-like TiO2 with anatase/TiO2 phase interfaces and a highly specific exterior level using a user-friendly and green deep eutectic solvent-tuning method. This impressive outer layer is the result of the 3D-ranked assembly of 2D ultrathin nanosheets with mesopores. Additionally, we have successfully fabricated Gd2ZnMnO6/Zn2MnO4 nanospheres on dendritic fibrous nanotitanium (DFNT@Gd2ZnMnO6/Zn2MnO4) via a facile synthetic pathway. Notably, the overall mapping of the DFNT@Gd2ZnMnO6/Zn2MnO4 composite remained largely unchanged after the loading of Gd2ZnMnO6/Zn2MnO4, and its mesoporous architecture and crystalline morphology were preserved. The investigation of diverse DFNT@Gd2ZnMnO6/Zn2MnO4 configurations as a nanocatalysts for the preparation of 3-aryl-2-oxazolidinones by anilines, carbon dioxide, and olefins was also conducted. It demonstrated appropriate stability over ten cycles, indicating its potential as a highly proficient catalyst to mitigate environmental concerns.

Dendritic fibrous nano-titanium (DFNT) with highly dispersed poly(ionic liquids) as a nanocatalyst for synthesis of dimethyl carbonate from methanol and carbon dioxide

The simultaneous fabrication of a phase junction and fibrous anatomy is able to ameliorate the separation, catalytic power, and catalytic activity of nano TiO2. However, It's easy and green fabrication is still essentially required. Here, an advanced dandelion-like TiO2 with anatase/TiO2 phase interface and the high particular outer layer was well created by a convenient and eco-friendly deep eutectic solvent-tuning approach. The large specific outer layer is the result of its 3D hierarchical anatomy assembled by 2D ultrathin nanosheets with mesopores. We fabricated Polyoxomolybdate [Mo132] nanospheres with various ionic liquid groups loaded on dendritic fibrous nanotitanium (DFNT@IL/Mo132) employing an unchallenging synthetic path. DFNT could provide abundant hydroxyl groups for uniform loading of IL through chemical bonding interaction, while IL could adjust the appropriate fiber dimension and show the active adsorption sites of amino groups that contribute to chemisorption with CO2. The overall topography of the DFNT@IL/Mo132 composite did not considerably alter after IL/Mo132 loading, and its mesoporous anatomy as well as crystal line shape were still sustained. This catalyst suffers from a low rate of DMC formation for the direct production of dimethyl carbonate (DMC) from methanol and CO2 due to its small specific outer layer and less active sites. In the current paper, we improved the issueby uniform dispersion of doped IL/Mo132 DFNT-based metal–organic frameworks (DFNT@IL/Mo132), which were produced through anamended hydrothermal approach.

Low-temperature NH3-SCR reaction over 3D Cu/Fe-TiO2-rGO composite catalyst synthesized by photoreduction method

Nitrogen oxides is a typical atmospheric pollutant and selective catalytic reduction with NH3 is an efficient and commonly used solution to remove NO from power plants and factories. In this paper, the Cu/Fe-TiO2-rGO catalysts with 3D hierarchical dandelion-like TiO2 microspheres and reduced graphene oxide as carrier were prepared by photocatalytic reduction method. The catalyst possessed the improved NO removal rate due to the following advantages: firstly, graphene oxide improved the specific surface area of Cu/Fe-TiO2-rGO catalyst. In addition, the Fe species promoted NH3 desorption and increased the oxidation of Cu species leading to the improvement of the low temperature activity of the catalyst. In another aspect, the amount of graphene oxide used to prepare MOx/GO by common hydrothermal method is large. The catalyst synthesized by photoreduction method with less amount and higher dispersion degree of reduced graphene oxide possessed the best NO conversion rate over 97 % at 250 °C, and Cu and Fe species were simultaneously distributed on the surface of rGO and 3D TiO2 microspheres. What was more, a large number of Lewis acid sites and a small amount of Brönsted acid sites in the catalysts were detected, and Fe element improved the NO conversion of Cu0.4Fe0.6-TiO2-rGO sample by Langmuir–Hinshelwood mechanism.

Nitrogen-doped carbon-coated hierarchical Li4Ti5O12-TiO2 hybrid microspheres as excellent high rate anode of Li-ion battery

Abstract Nitrogen-doped carbon-coated Li4Ti5O12-TiO2 (LTO-TO) hybrid microspheres were prepared by heat treating the dry mixture of urea and chemically lithiated dandelion-like TiO2 microspheres in a stainless steel autoclave at 550 °C for 5 h. The hybrid materials were tested as anode of Li-ion batteries. As compared to the pristine sample, the N-doped carbon-coated LTO-TO microspheres exhibited higher specific capacity at both low and high current rates. Discharge capacities of 184 and 123 mAh g−1 were obtained at 0.2 C and 20 C, respectively. Moreover, the LTO-TO/C electrode showed excellent cycle performance, with a discharge capacity of 121.3 mAh g−1 remained after 300 cycles at 5 C, corresponding to an average capacity degradation rate of 0.073% per cycle. These high specific capacity, excellent rate capability and cycle performance demonstrated the high potentiality of the N-doped carbon-coated LTO-TO microspheres as anode material of both energy storage-type and power-type Li-ion batteries.

The improvement of light scattering of dye-sensitized solar cells aided by a new dandelion-like TiO2 nanostructures

We present a new dandelion-like TiO2 spheres by a modified hydrothermal method for manufacture of dye-sensitized solar cells (DSSCs). This construct is composed of numerous nanowires for employment as the scattering layer of DSSCs. Such morphology is produced by nucleation-growth-assembly mechanism. The size of the dandelion-like spheres and their morphology can be tailored by controlling the processing parameters of the modified hydrothermal process. TiO2 nanoparticles with narrow size distribution are also synthesized by hydrothermal route for the active layer of DSSCs. The nanoparticles show pure anatase phase with average size of 40nm, whereas the dandelion-like TiO2 spheres are pure rutile structure with average diameter in the range 5–9μm. A systematic study is performed in order to improve the photovoltaic performance of the DSSCs with different arrangement modes. First, the monolayer DSSCs with various thicknesses are prepared using pure nanoparticles. The highest power conversion efficiency (PCE) of 7.4% is obtained for the monolayer cell with thickness of 31μm. Second, the double layer DSSCs containing an under-layer and an over-layer are reported. The double layer DSSC made of nanoparticles as the under-layer (with thickness around 31μm) and mixtures of nanoparticles and dandelion-like spheres as the over-layer (as light scattering layer with thickness around 8μm) shows the highest PCE of 8.3%. The improvement of cell efficiency is explained by triple function mechanism including significant increase in light scattering, dye sensitization and photo-generated charge carriers.

Preparation, Characterization and Growth Mechanism of Dandelion-like TiO2 Nanostructures and their Application in Photocatalysis towards Reduction of Cr(VI)

Three-dimensional (3D) dandelion-like TiO2 nanostructures were successfully synthesized from TiCl4 and water via simple hydrothermal method. The samples were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). The photocatalytic activity of the dandelion-like TiO2 nanostructures was evaluated by photoreduction of Cr(VI) under UV light irradiation. The results indicated that the dandelion-like rutile TiO2 nanostructures were composed of ordered nanorods with an average diameter of 17nm. Furthermore the results indicated that the dandelion-like TiO2 can be easily scaled-up and reproducible. The growth mechanism of the dandelion-like TiO2 nanostructures has been proposed to occur in a four-step reaction, i.e., (i) nucleation and nanoparticle formation; (ii) formation of spheres through self-assembly growth; (iii) further growth and (iv) agglomeration of the dandelions to form flower-like rutile TiO2. The dandelion-like TiO2 structures exhibited higher photocatalytic efficiency compared to P25 TiO2 for the photoreduction of Cr(VI). The highest photocatalytic reduction rate was with 2g of the catalyst in a 10mg/L Cr(VI) solution with pH 2. The high photocatalytic activity of the dandelion-like TiO2 nanostructures was attributed to the flower-like morphology, highest light-harvesting efficiency resulted from multiple reflections of light, hierarchical mesoporous structure and large specific surface area (81 m2/g).

One-pot synthesis of 3-D dandelion-like architectures constructed by rutile TiO2 nanorods grown along [001] axis for high-rate lithium ion batteries

A novel 3-D dandelion-like TiO2 anode constructed by rutile nanorods grown along [001] axis exhibits high-rate lithium ion battery behaviour.

Substrate placement angle-dependent growth of dandelion-like TiO2nanorods for solid-state semiconductor-sensitized solar cells

Hierarchical nanostructures grown directly on transparent conducting oxides hold the promise of overcoming the limitations of current semiconductor-sensitized solar cells based on random networks of nanoparticles. Here, we develop a facile substrate placement angle-dependent hydrothermal process to grow dandelion-like TiO2 nanostructures directly on transparent conductive oxides. TiO2 nanocrystals grown in solution during the synthesis process are found to promote the dandelion-like structure. By using these TiO2 nanostructures as photoanodes, Sb2S3 as the sensitizer, and P3HT as the hole-transporting material, we demonstrate fabrication of all-solid-state semiconductor-sensitized solar cells, which yield solar power conversion efficiency up to 4.71%. Electrochemical impedance spectroscopy indicates that moderate rod fusion at the base beneficially reduces electron recombination in the device. This work provides an innovative method for growing branched, one-dimensional TiO2 nanostructures that can be used for energy harvesting and storage.

Decoration of reduced graphene oxide with dandelion-like TiO2 and their dielectric properties in poly(arylene ether nitriles) composites

Novel dandelion-like titanium oxide (TiO2) decorated reduced graphene oxide (rGO@TiO2) hybrids were obtained by a one-step solvent-thermal reduction of GO and tetrabutyl titanate simultaneously. The hybrids were used as a novel filler for high performance poly(arylene ether nitriles) (PEN) composites. The thermal stability and morphological properties of the PEN composites were, respectively, investigated by the thermo gravimetric analysis and scanning electron microscope, aiming at examining the effect of surface decoration on the dispersion of rGO@TiO2 in PEN matrix. The results indicated that the rGO@TiO2 present better dispersion in the PEN matrix. Meanwhile, the derived composite films exhibited high thermal stability with initial decomposition temperatures (T id ) in the range of 477–487 °C. DSC curves showed that the glass transition temperatures were in the range of 219–227 °C. Moreover, all of the composite films also showed excellent flexibility and mechanical properties. The tensile modulus and strength were increased about 4 and 6 % with 5 wt% rGO@TiO2 loading, respectively. More importantly, for 30 wt% rGO@TiO2 reinforced PEN composite film, the dielectric permittivity dramatically increased from 3.8 to 81 at 1 kHz.

Facile and effective synthesis of hierarchical TiO2 spheres for efficient dye-sensitized solar cells

Three-dimensional (3D) crystalline anatase TiO2 hierarchical spheres were successfully derived from Ti foils via a fast, template-free, low-temperature hydrothermal route followed by a calcination post-treatment. These dandelion-like TiO2 spheres are composed of numerous ultrathin nanoribbons, which were subsequently split into fragile nanoflakes as a result of the decomposition of Ti-complex intermediates to TiO2 and H2O at high temperature. The dye-sensitized solar cells (DSSCs) employing such hierarchically structured TiO2 spheres as the photoanodes exhibited a light-to-electricity conversion efficiency of 8.50%, yielding a 28% enhancement in comparison with that (6.64%) of P25-based DSSCs, which mainly benefited from the enhanced capacity of dye loading in combination with effective light scattering and trapping from hierarchical architecture.

Synthesis of dandelion-like TiO2 microspheres as anode materials for lithium ion batteries with enhanced rate capacity and cyclic performances

Dandelion-like TiO2 microspheres consisting of numerous rutile single-crystalline nanorods were synthesized for the first time by a hydrothermal method. Their crystal structure, morphology and electrochemical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and galvanostatic charge and discharge tests. The results show that the synthesized TiO2 microspheres exhibit good rate and cycle performances as anode materials of lithium ion batteries. It can be found that the dandelion-like structure provides a larger specific surface area and the single-crystalline nanorod provides a stable structure and fast pathways for electron and lithium ion transport, which contribute to the rate and cycle performances of the battery.

Effects of acid on the microstructures and properties of three-dimensional TiO2 hierarchical structures by solvothermal method

Three-dimensional (3D) TiO2 hierarchical structures with various microstructures have been successfully synthesized via a surfactant-free and single-step solvothermal route, in which hydrochloric acid (HCl), nitric acid (HNO3), and acetic acid (HAc) are employed as the acid medium, respectively. The effects of acid medium on the microstructures and properties of 3D TiO2 hierarchical structure have been studied. The results indicate that 3D dandelion-like microspheres assembled of radial rutile nanorods are obtained in the sample prepared with HCl. Both the fraction of rutile and the diameter of nanorod enhance with the increasing HCl concentration. For the products derived from either HNO3 or HAc, 3D spheres composed of anatase nanoparticles are present. The 3D dandelion-like TiO2 hierarchical structures show low reflectance and efficient light harvesting since this ordered rod geometry offers a light-transfer path for incident light as well as multiple reflective and scattering effects. Moreover, 3D TiO2 with this unique topology shows superior photocatalytic activity despite low surface area, which can be ascribed to the enhanced light harvesting, fast electron transport, and low electron/hole recombination loss.

Solvent-controlled synthesis of three-dimensional TiO2 nanostructures via a one-step solvothermal route

Three-dimensional (3D) TiO2 nanostructures with various microstructures have been successfully synthesized by altering the solventvia a surfactant-free and single-step solvothermal route. The effects of the solvent on the microstructures of 3D TiO2 nanostructures were investigated. 3D dandelion-like TiO2 structures self-assembled of nanorods were synthesized in non-polar solvent based on water–non-polar solvent interface. For the product derived from the solvent of n-hexane, the 3D microspheres have a homogeneous size distribution in diameter of about 2 μm and a uniform morphology of radially packed nanorods of 15 nm in diameter along a [001] preference growth direction. A three-step growth model is proposed to illustrate the growth mechanism of TiO2 nanorods self-assembled into 3D dandelion-like structures. Microspheres composed of nanoparticles are obtained using low polar or polar solvent such as n-butyl alcohol and ethanol, which are also amphiphilic solvents. The amphiphile bilayer capped outside the particle serves as the microreactor and soft temple for crystal growth. Only bulky aggregated TiO2 nanoparticles were obtained when pure water is used as the solvent due to the fast hydrolysis of titanium precursor. Mechanisms of the self-assembly of 3D TiO2 structures in different solvents were proposed.

Novel three-dimensional dandelion-like TiO 2 structure with high photocatalytic activity

Pure rutile phase crystalline TiO 2 powder with novel 3D dandelion-like structure was synthesized by using a facile hydrothermal method with TiCl 3 as the main starting material. In such a 3D structure, the nanometer-scale construction elements aggregate together and form a micrometer-scale artificial unit. The typical 3D dandelion structure has an average diameter of 1.5–2 μm and is packed radially by nanorods with [001] preference growth direction. Each individual nanorod is hundreds of nanometers in length, and tens of nanometers in diameter. The obtained 3D dandelion-like TiO 2 powder has a high photocatalytic activity, which is equivalent to that of the commercial available P25 titania powder. Mechanisms of the formation of the dandelion-like structure were also discussed. A different oxidation process of Ti(III) to Ti(IV) during hydrothermal was suggested.

Preparation and characterization of doped TiO 2 nanodandelion

Doped dandelion-like TiO 2 microspheres assembled nanorods were synthesized from rutile powders using either urea or thiourea leading to N- or S-doped TiO 2. The rutile particles reacted in concentrated NaOH and urea (or thiourea) solution under hydrothermal conditions (200 °C for 24 h), yielding N- and S-doped TiO 2 nanodandelions with diameters ranging from 0.7 to 1.3 μm. SEM, HRTEM, X-ray diffraction (XRD) and IR spectra were used to characterize the synthesis of powders. The results show that concentrated urea (or thiourea) and NaOH are used as additives that help in the construction of the dandelion-like structures. The fabricated nanostructures exhibit high photocatalytic activity in the photodegradation of aqueous Methylene Blue solution.