Showing papers by "Wuhan University of Technology published in 2010"
TL;DR: In this article, a simple hydrothermal route in a Ti(OC4H9)4-HF-H2O mixed solution followed by a photochemical reduction deposition of Pt nanoparticles on TiO2 nanosheets under xenon lamp irradiation is described.
Abstract: Pt/TiO2 nanosheets with exposed (001) facets were fabricated by a simple hydrothermal route in a Ti(OC4H9)4-HF-H2O mixed solution followed by a photochemical reduction deposition of Pt nanoparticles on TiO2 nanosheets under xenon lamp irradiation. The prepared samples were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption−desorption isotherms, UV−vis diffuse reflectance spectroscopy, and photoluminescence (PL) spectroscopy. Production of •OH radicals on the TiO2 surface was detected by the PL technique using coumarin as a probe molecule. The effects of Pt loading on the rates of photocatalytic hydrogen production of the as-prepared samples in ethanol aqueous solution were investigated and discussed. The results showed that the photocatalytic hydrogen production rates of TiO2 nanosheets from the ethanol aqueous solutions were significantly enhanced by loaded Pt on the TiO2 nanosheets, and the latter with a 2 wt % of deposited Pt exhi...
1,058 citations
TL;DR: The surface chemistry and the surface structure at the atomic level are key factors in tuning the adsorption selectivity and, consequently, photocatalytic selectivity of HTS toward azo dyes.
Abstract: A fluoride mediated self-transformation method is proposed for the synthesis of hollow TiO2 microspheres (HTS) composed of anatase polyhedra with exposed ca. 20% {001} facets. Importantly, HTS exhibit tunable photocatalytic selectivity in decomposing azo dyes in water. The fluorinated HTS show preferential decomposition of methyl orange (MO) in comparison to methylene blue (MB). In contrast, the surface-modified HTS by either NaOH washing or calcinations at 600 °C favor decomposition of MB over MO. The surface chemistry and the surface structure at the atomic level are key factors in tuning the adsorption selectivity and, consequently, photocatalytic selectivity of HTS toward azo dyes.
982 citations
TL;DR: It is demonstrated that ultralong hierarchical vanadium oxide nanowire is one of the most favorable nanostructures as cathodes for improving cycling performance of lithium ion batteries.
Abstract: Ultralong hierarchical vanadium oxide nanowires with diameter of 100−200 nm and length up to several millimeters were synthesized using the low-cost starting materials by electrospinning combined with annealing. The hierarchical nanowires were constructed from attached vanadium oxide nanorods of diameter around 50 nm and length of 100 nm. The initial and 50th discharge capacities of the ultralong hierarchical vanadium oxide nanowire cathodes are up to 390 and 201 mAh/g when the lithium ion battery cycled between 1.75 and 4.0 V. When the battery was cycled between 2.0 and 4.0 V, the initial and 50th discharge capacities of the nanowire cathodes are 275 and 187 mAh/g. Compared with self-aggregated short nanorods synthesized by hydrothermal method, the ultralong hierarchical vanadium oxide nanowires exhibit much higher capacity. This is due to the fact that self-aggregation of the unique nanorod-in-nanowire structures have been greatly reduced because of the attachment of nanorods in the ultralong nanowires,...
553 citations
TL;DR: In this article, surface-fluorinated anatase TiO 2 nanosheets with dominant {0,0,1} facets were fabricated by a simple hydrothermal route in a Ti(OC 4 H 9 ) 4 -HF-H 2 O mixed solution.
Abstract: Surface-fluorinated anatase TiO 2 nanosheets with dominant {0 0 1} facets were fabricated by a simple hydrothermal route in a Ti(OC 4 H 9 ) 4 -HF-H 2 O mixed solution. The atomic ratios of fluorine to titanium ( R F ) exhibit an obvious influence on the structures and photocatalytic activity of TiO 2 samples. In the presence of HF, TiO 2 nanosheets can be easily obtained. With increasing R F , the relative anatase crystallinity, average crystallite size, pore size and percentage of exposed {0 0 1} facets increase, contrarily, BET specific surface areas decrease. All fluorinated TiO 2 nanosheets exhibit much higher photocatalytic activity than Degussa P-25 TiO 2 (P25) and pure TiO 2 nanoparticles prepared in pure water due to the synergistic effect of surface fluorination and exposed {0 0 1} facets on the photoactivity of TiO 2 . Especially, at R F = 1, the fluorinated TiO 2 nanosheet exhibits the highest photocatalytic activity, and its photoactivity exceeds that of P25 by a factor of more than nine times.
490 citations
TL;DR: The results of high-resolution electron microscopy and small angle and inelastic neutron scattering along with corresponding thermoelectric property measurements corroborate that the 10-20 nm nanocrystalline domains with coherent boundaries are the key constituent that accounts for the resulting exceptionally low lattice thermal conductivity and significant improvement of ZT.
Abstract: Herein, we report the synthesis of multiscale nanostructured p-type (Bi,Sb)2Te3 bulk materials by melt-spinning single elements of Bi, Sb, and Te followed by a spark plasma sintering process. The samples that were most optimized with the resulting composition (Bi0.48Sb1.52Te3) and specific nanostructures showed an increase of ∼50% or more in the figure of merit, ZT, over that of the commercial bulk material between 280 and 475 K, making it suitable for commercial applications related to both power generation and refrigeration. The results of high-resolution electron microscopy and small angle and inelastic neutron scattering along with corresponding thermoelectric property measurements corroborate that the 10−20 nm nanocrystalline domains with coherent boundaries are the key constituent that accounts for the resulting exceptionally low lattice thermal conductivity and significant improvement of ZT.
487 citations
TL;DR: The prepared TiO(2) nanosheet film electrode should also find wide-ranging potential applications in various fields including photocatalysis, catalysis, electrochemistry, separation, purification and so on.
Abstract: Dye-sensitized solar cells (DSSCs) are fabricated based on anatase TiO2 nanosheets (TiO2-NSs) with exposed {001} facets, which were obtained by a simple one-pot hydrothermal route using HF as a morphology controlling agent and Ti(OC4H9)4 as precursor. The prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis absorption spectroscopy and N2 adsorption-desorption isotherms. The photoelectric conversion performances of TiO2-NSs solar cells are also compared with TiO2 nanoparticles (TiO2-NPs) and commercial-grade Degussa P25 TiO2 nanoparticle (P25) solar cells at the same film thickness, and their photoelectric conversion efficiencies (η) are 4.56, 4.24 and 3.64%, respectively. The enhanced performance of the TiO2-NS solar cell is due to their good crystallization, high pore volume, large particle size and enhanced light scattering. The prepared TiO2 nanosheet film electrode should also find wide-ranging potential applications in various fields including photocatalysis, catalysis, electrochemistry, separation, purification and so on.
442 citations
TL;DR: In this article, high-ordered TiO2 nanotube arrays (TNs) are prepared by electrochemical anodization of titanium foil in a mixed electrolyte solution of glycerol and NH4F and then calcined at various temperatures.
Abstract: Highly ordered TiO2 nanotube arrays (TNs) are prepared by electrochemical anodization of titanium foil in a mixed electrolyte solution of glycerol and NH4F and then calcined at various temperatures The prepared samples are characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy The photocatalytic activity is evaluated by photocatalytic degradation of methyl orange (MO) aqueous solution under UV light irradiation The production of hydroxyl radicals ( OH) on the surface of UV-irradiated samples is detected by a photoluminescence (PL) technique using terephthalic acid (TA) as a probe molecule The transient photocurrent response is measured by several on–off cycles of intermittent irradiation The results show that low temperatures (below 600 °C) have no great influence on surface morphology and architecture of the TNs sample and the prepared TNs can be stable up to ca 600 °C At 800 °C, the nanotube arrays are completely destroyed and only dense rutile crystallites are observed The photocatalytic activity, formation rate of hydroxyl radicals and photocurrent of the TNs increases with increasing temperatures (from 300 to 600 °C) due to the enhancement of crystallization Especially, at 600 °C, the sample shows the highest photocatalytic activity due to its bi-phase composition, good crystallization and remaining tubular structures With further increase in the calcination temperature from 600 to 800 °C, the photocatalytic activity rapidly decreases due to the vanishing of anatase phase, collapse of nanotube structures and decrease of surface areas
399 citations
TL;DR: The as-prepared Ag-TiO(2) nanocomposite hollow spheres at the nominal atomic ratio of silver to titanium (R) of 2 showed the highest photocatalytic activity, which exceeds that of P25 by a factor of more than 2.
Abstract: Visible-light-driven plasmonic photocatalyst Ag-TiO(2) nanocomposite hollow spheres are prepared by a template-free chemically-induced self-transformation strategy under microwave-hydrothermal conditions, followed by a photochemical reduction process under xenon lamp irradiation. The prepared samples are characterized by using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, N(2) adsorption-desorption isotherms, X-ray photoelectron spectroscopy, UV/Vis and Raman spectroscopy. Production of .OH radicals on the surface of visible-light illuminated TiO(2) was detected by using a photoluminescence method with terephthalic acid as the probe molecule. The photocatalytic activity of as-prepared samples was evaluated by photocatalytic decolorization of Rhodamine B (RhB) aqueous solution at ambient temperature under visible-light irradiation. The results show that the surface plasmon absorption band of the silver nanoparticles supported on the TiO(2) hollow spheres was red shifted, and a strong surface enhanced Raman scattering effect for the Ag-TiO(2) nanocomposite sample was observed. The prepared nanocomposite hollow spheres exhibits a highly visible-light photocatalytic activity for photocatalytic degradation of RhB in water, and their photocatalytic activity is higher than that of pure TiO(2) and commercial Degussa P25 (P25) powders. Especially, the as-prepared Ag-TiO(2) nanocomposite hollow spheres at the nominal atomic ratio of silver to titanium (R) of 2 showed the highest photocatalytic activity, which exceeds that of P25 by a factor of more than 2.
323 citations
TL;DR: In this paper, a simple cation exchange using hydrothermally synthesized ZnS nanoparticles (NPs) and Cd(NO3)2 precursors was used to obtain high visible-light photocatalytic H2-production activity from aqueous solutions containing Na2SO3 and Na2S as sacrificial reagents.
322 citations
TL;DR: In this paper, a sacrificial template-accelerated hydrolysis (STAH) approach was proposed for the synthesis of iron oxide-based nanotube arrays including hematite α-Fe2O3 and magnetite Fe3O4 on centimeterscale conducting alloy substrates.
Abstract: We report a novel “sacrificial template-accelerated hydrolysis” (STAH) approach to the synthesis of iron oxide-based nanotube arrays including hematite α-Fe2O3 and magnetite Fe3O4 on centimeter-scale conducting alloy substrates. ZnO nanowire arrays are chosen as the inexpensive and sacrificial templates that do not contribute to the component of final iron oxide nanotubes but can be in situ dissolved by the acid produced from the Fe3+ precursor hydrolysis. Interestingly, the ZnO template dissolution in turn accelerates the Fe3+ hydrolysis, which is essential to initiating the nanotube formation. Such a STAH approach provides a morphology-reservation transformation, when various shaped ZnO templates are adopted. Moreover, by introducing glucose into the precursor solution, we also successfully obtain carbon/hematite(C/α-Fe2O3) composite nanotube arrays on large-area flexible alloy substrate, with a large number of pores and uniform carbon distribution at a nanoscale in the nanotube walls. These arrays have...
318 citations
TL;DR: In order to identify the correlation of CPA, which is a key indicator for collision avoidance, with ship's size, speed, and course, linear regression models are developed and a dynamic method based on SAMSON is presented.
TL;DR: In this paper, a sequential evolution process involving surface deposition, mutual diffusion, interior dissolution, and interfacial reaction is proposed to account for the formation of CuS/ZnS hollow spheres.
Abstract: Monodisperse CuS/ZnS nanocomposite hollow spheres with diameters of about 255 nm and shells composed of nanoparticles have been successfully synthesized in high yield by an ion-exchange method using monodisperse ZnS solid spheres as a precursor. The prepared samples were characterized by X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption−desorption isotherms, and UV−visible absorption spectroscopy. The photocatalytic activity was evaluated by the photocatalytic decolorization of Rhodamine B (RhB) aqueous solution under visible-light irradiation. The results indicate that the difference of solubility products (Ksp) of ZnS and CuS is the main driving force for the formation of CuS/ZnS hollow spheres. A sequential evolution process involving surface deposition, mutual diffusion, interior dissolution, and interfacial reaction is proposed to account for the formation of CuS/ZnS nanocomposite hollow spheres. The reaction time greatly influences the ...
TL;DR: An efficient Fe(2)O(3)-pillared rectorite (Fe-R) clay was successfully developed as a heterogeneous catalyst for photo-Fenton degradation of organic contaminants and showed good stability for the degradation of RhB after five recycles.
Abstract: An efficient Fe(2)O(3)-pillared rectorite (Fe-R) clay was successfully developed as a heterogeneous catalyst for photo-Fenton degradation of organic contaminants. X-ray diffraction analysis and high-resolution transmission electron microscope analysis clearly showed the existence of the Fe(2)O(3) nanoparticles in the Fe-R catalyst. The catalytic activity of the Fe-R catalyst was evaluated by the discoloration and chemical oxygen demand (COD) removal of an azo-dye rhodamine B (RhB, 100 mg/L) and a typical persistent organic pollutant 4-nitrophenol (4-NP, 50 mg/L) in the presence of hydrogen peroxide (H(2)O(2)) under visible light irradiation (lambda > 420 nm). It was found that the discoloration rate of the two contaminants was over 99.3%, and the COD removal rate of the two contaminants was over 87.0%. The Fe-R catalyst showed strong adsorbability for the RhB in the aqueous solution. Moreover, the Fe-R catalyst still showed good stability for the degradation of RhB after five recycles. Zeta potential and Fourier transform infrared spectroscopy were used to examine the photoreaction processes. Finally, a possible photocatalytic mechanism was proposed.
TL;DR: In this paper, high-ordered TiO2 nanotube array (TNs) thin films were prepared by electrochemical anodization of titanium foil in a mixed electrolyte solution containing Na2SO4, H3PO4, NaF, and sodium citrate and then treated by calcination, vapor-thermal, and hydrothermal methods, respectively.
Abstract: Highly ordered TiO2 nanotube array (TNs) thin films were prepared by electrochemical anodization of titanium foil in a mixed electrolyte solution containing Na2SO4, H3PO4, NaF, and sodium citrate and then treated by calcination, vapor-thermal, and hydrothermal methods, respectively. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The photocatalytic activity of the film samples was evaluated by photocatalytic degradation of methyl orange (MO) aqueous solution under UV light irradiation. The production of hydroxyl radicals (•OH) on the surface of UV-irradiated samples was detected by a photoluminescence technique using terephthalic acid as a probe molecule. The transient photocurrent response was measured by several on−off cycles of intermittent irradiation. It was found that post-treatment exhibited a great influence on the morphology, crystallization, and photocatalytic activity of TNs th...
TL;DR: In this article, an Ag/ZnO photocatalytic reduction of Ag+ on ZnO with ethanol as hole scavenger was found to not only enhance its photocatalysis but also improve its photostability.
Abstract: Ag/ZnO photocatalysts with different Ag loadings were prepared by photocatalytic reduction of Ag+ on ZnO with ethanol as hole scavenger. It was found that loading an appropriate amount of Ag on ZnO not only enhances its photocatalytic activity, but also improves its photostability. The Ag/ZnO photocatalysts were characterized with XRD, BET, DRUV–vis, Raman, PL, and photoelectrochemical measurement. No matter what the Ag loading is higher or low, silver exists in the form of metallic species in the Ag/ZnO photocatalysts. The enhancement of photocatalytic activity is due to the fact that the modification of ZnO with an appropriate amount of Ag can increase the separation efficiency of photogenerated electrons and holes in ZnO, and the improvement of photostability of ZnO is attributed to a considerable decrease of the surface defect sites of ZnO after the Ag loading. The chemisorption of molecular oxygen and the chemisorption of atomic oxygen on Ag in the Ag/ZnO photocatalysts were observed. It was found that the metallic Ag in the Ag/ZnO photocatalysts does play a new role of O2 chemisorption sites except for electron acceptor, by which chemisorbed molecular oxygen reacts with photogenerated electrons to form active oxygen species, and thus facilitates the trapping of photogenerated electrons and further improves the photocatalytic activity of the Ag/ZnO photocatalysts.
TL;DR: A novel device of coupling photodegradation with light-to-electricity conversion was developed, which is a promising candidate for the photocatalytic removal of dye pollutants and a renewable energy source.
Abstract: Through comparing the photocatalytic performance of microscale ZnO, nano ZnO, and Degussa P25 titania (P25), it was found that the microscale ZnO exhibited 2.6-35.7 times higher photocatalytic activity for the photodegradation of various dye pollutants than P25 under both UV-visible and visible irradiation and showed much better photostability than the nano ZnO. The photocatalysts were characterized with XRD, Raman, BET, DRUV-vis, adsorption of dye, photoelectrochemical measurement, and PL. The much higher photocataltyic activity of the microscale ZnO than P25 under UV-visible irradiation is attributed to the higher efficiency of generation, mobility, and separation of photoinduced electrons and holes. The much higher visible photocataltyic activity of the microscale ZnO than P25 is due to the higher photosensitization efficiency of electron transfer from an excited dye to the conduction band of the microscale ZnO than that of P25. The much better photostability of the microscale ZnO than the nano ZnO is due to its better crystallinity and lower defects. The photostability of the microscale ZnO is greatly improved by the surface modification of ZnO with a small amount of TiO(2). On the basis of the excellent photocatalytic performance of the microscale ZnO and TiO(2)-modified ZnO, a novel device of coupling photodegradation with light-to-electricity conversion was developed, which is a promising candidate for the photocatalytic removal of dye pollutants and a renewable energy source.
TL;DR: In this article, hierarchical spindle-like Al2O3 materials were prepared in the form of fray ended bundles of twisted nanoflakes by a non-template hydrothermal synthesis and sequential calcination route using aluminium nitrate or aluminium chloride as precursors and urea as precipitating agent.
Abstract: Hierarchical spindle-like γ-Al2O3 materials were prepared in the form of fray ended bundles of twisted nanoflakes by a non-template hydrothermal synthesis and sequential calcination route using aluminium nitrate or aluminium chloride as precursors and urea as precipitating agent. The microstructures, morphologies and textural properties of the resulting materials were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and N2 adsorption–desorption techniques. It was found that the spindle-like γ-Al2O3 particles are composed of at least three levels of hierarchical organization: polycrystalline γ-Al2O3 at the nanoscale, oriented nanoflakes and uniform spindle-like assemblies. The hierarchical γ-Al2O3 particles prepared from aluminium nitrate show a slightly smaller size, fewer self-organized nanoplatelets and better textural properties than γ-Al2O3 prepared from aluminium chloride, due to the larger aqueous ionic radius of NO3− than that of Cl−. The reported experiments allowed us to propose the mechanism of formation of the spindle-like assemblies, which involves self-transformation of metastable amorphous aluminium hydroxide particles and their sequential cooperative assembly. The as-prepared γ-Al2O3 was found to be effective adsorbent for the removal of selective pollutants from wastewater as a result of its unique hierarchical structure and high specific surface area, indicating a promising potential of this material for environmental remediation.
TL;DR: In this article, surface-fluorinated TiO2 hollow microspheres and tabular-shaped anatase single micro-crystals with highly energetic (001) facets exposed were prepared by a one-step hydrothermal strategy using ammonium bifluoride (NH4HF2) as a morphology controlling agent.
Abstract: Surface-fluorinated TiO2 hollow microspheres and tabular-shaped anatase single micro-crystals with highly energetic (001) facets exposed were prepared by a one-step hydrothermal strategy using ammonium bifluoride (NH4HF2) as a morphology controlling agent. The prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and N2 adsorption–desorption isotherms. Production of ˙OH radicals on the TiO2 surface was detected by a photoluminescence (PL) technique using terephthalic acid as a probe molecule. The photocatalytic activity of the as-prepared samples was evaluated by photocatalytic decolorization of Rhodamine B (RhB) aqueous solution at ambient temperature. The results indicate that the particle morphology, average crystallite size, specific surface areas, pore structures, and photocatalytic activity of the TiO2 samples can be readily controlled by changing the concentration of NH4HF2. With increasing NH4HF2 concentration, the average crystallite size and average pore size increase, whilst the specific surface area, pore volume and porosity steadily decrease. The photocatalytic activity of the as-prepared samples exceeds that of Degussa P25 (P25) when the molar ratios of fluorine to titanium (RF) are kept in the range of 0 to 1.
TL;DR: This work presents a new mesoporous-based approach to approximating the viscosity-to-oxide ratio of Na6(CO3)(SO4)2, which has shown Promise in Materials Synthesis and Processing and its Applications in Materials Science and Engineering.
Abstract: [ ∗] Dr. B. Hu , Ding , . Y D. Kulkarni , Shen , . Y Prof. sukruk , T . V. V Prof. Z. L. Wang School of Materials Science and Engineering Georgia Institute of TechnologyAtlanta, GA 30332-0245 (USA) E-mail: zhong.wang@mse.gatech.edu Dr. B. Hu , Prof. W Chen .State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Materials Science and Engineering Wuhan University of Technology Wuhan, 430070 (P. R. China) E-mail: chenw@whut.edu.cn
TL;DR: The dynamic remove of Crystal Violet by Semi-IPN hydrogels constituted of poly(acrylic acid-acrylamide-methacrylate) and amylose was studied and it was found that the sorption process agreed very well with the Langmuir model and the adsorption of CV depended on the length of the side chain,Amylose content and pH of the solution.
TL;DR: In this article, the photocatalytic activity of core-shell nanocomposite nanowires was evaluated for the decolorization of Rhodamine B (RhB) aqueous solution at ambient temperature under UV-light irradiation.
TL;DR: In this article, the interaction and adsorptive removal of ciprofloxacin (CIP) with a sodium montmorillonite (MMT) were studied in batch tests and supplemented by XRD and FTIR analyses.
TL;DR: The molar ratios of NH(4)F to TiO(2) (R) exhibit a significant influence on the morphology and photocatalytic activity of the TiO (2) samples and a possible formation mechanism by localized Ostwald ripening or chemically induced self-transformation is proposed based on the experimental observations.
Abstract: Mesporous anatase-phase TiO2 hollow spheres with high photocatalytic activity were prepared by hydrothermal treatment and self-transformation of amorphous TiO2 solid spheres in an NH4F aqueous solution. The prepared samples were characterized by X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption-desorption isotherms and UV-vis absorption spectroscopy. The photocatalytic activity was evaluated by photocatalytic oxidation decomposition of acetone in air under UV irradiation. It is found that F− plays an essential role in the formation of TiO2 hollow spheres. F− not only induces the hollowing of TiO2 solid spheres, but also promotes the crystallization of anatase TiO2 nanocrystals. A possible formation mechanism for the TiO2 hollow spheres by localized Ostwald ripening or chemically induced self-transformation is proposed based on the experimental observations. Furthermore, the molar ratios of NH4F to TiO2 (R) exhibit a significant influence on the morphology and photocatalytic activity of the TiO2 samples. The photocatalytic activity of the samples prepared in the presence of NH4F is higher than that of TiO2 sample prepared in pure water and commercial Degussa P25 (P25) powders. Especially, the TiO2 hollow spheres prepared at R = 1 show the highest photocatalytic activity and the specific rate constant Sk exceeds that of P25 by a factor of more than two.
TL;DR: In this article, hollow spherical mesoporous particles with tunable particle size and shell thickness were synthesized using latex templates and a silica precursor in a weakly basic ethanol−water mixture.
Abstract: Monodispersed hollow spherical mesoporous particles with tunable particle size and shell thickness were readily synthesized using latex templates and a silica precursor in a weakly basic ethanol−water mixture.
TL;DR: In this article, a series of hydrochloric acid-doped polyaniline (PANI) was prepared by chemical oxidative polymerization and the effects of HCl-doping concentration on the thermoelectric properties in the temperature range of 303-423 K were discussed.
TL;DR: In this article, the equiatomic multiprincipal CoCrFeNiCuAl high-entropy alloy was prepared using a vacuum arc melt casting method and the as-cast alloy was subsequently annealed at 1000°C for 2h and the annealing effects on the structure and properties evolution were investigated.
TL;DR: In this paper, the effect of positioning alkyl chains on DTBT on properties of polymers was investigated by investigating a small library of structurally related polymers with identical conjugated backbone.
Abstract: 4,7-Di(thiophen-2-yl)benzothiadiazole (DTBT) has been used to construct a number of donor−acceptor low band gap polymers for bulk heterojunction (BHJ) photovoltaics with high efficiency numbers. Its strong tendency to π-stack often leads to polymers with low molecular weight and poor solubility, which could potentially be alleviated by anchoring solubilizing chains onto the DTBT unit. A systematic study of the effect of positioning alkyl chains on DTBT on properties of polymers was implemented by investigating a small library of structurally related polymers with identical conjugated backbone. This series of donor−acceptor polymers employed a common donor unit, benzo[2,1-b:3,4-b′]dithiophene (BDT), and modified DTBT as the acceptor unit. Three variations of modified DTBT units were prepared with alkyl side chains at (a) the 5- and 6-positions of 2,1,3-benzothiadiazole (DTsolBT), (b) 3-positions of the flanking thienyl groups (3DTBT), and (c) 4-positions (4DTBT), in addition to the unmodified DTBT. Contrar...
TL;DR: In this paper, high-energy anatase TiO 2 photocatalysts with exposed {0,0,1} facets were tailored by hydrothermal reaction of tetrabutyl titanate (50 g) and HF solution at 200°C for 24h.
Abstract: In the present work, high-energy TiO 2 photocatalysts with exposed {0 0 1} facets were tailored by hydrothermal reaction of tetrabutyl titanate (50 g) and HF solution at 200 °C for 24 h. The photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, nitrogen adsorption–desorption isotherms and X-ray photoelectron spectroscopy. The photocatalytic activity of the photocatalyst was evaluated by a photoluminescence technique using coumarin as a probe molecule. It shows that, with increase in the amount of HF, the shape of TiO 2 evolves from octahedral bipyramid to nanosheet and the percentage of exposed high-energy {0 0 1} facets increases. The photocatalytic activity of the as-prepared high-energy anatase nanocrystals is positively related to the percentage of exposed {0 0 1} facets. When the amount of HF is more than 12 mL, the photocatalytic activity of anatase TiO 2 nanosheets is high than that of P25. The high photocatalytic activity of the high-energy anatase TiO 2 nanocrystals is ascribed to the synergetic effect of exposed high reactive {0 0 1} facets and surface fluorination. However, high concentrated HF (20 mL) results in the formation of cubic TiOF 2 , which shows very poor photocatalytic activity.
TL;DR: This work presents a simple and effective heterogeneous contraction method to fabricate hollow spheres with controllable interior structures by a non-equilibrium heat-treatment process of gel precursors with a high heating rate.
TL;DR: In this paper, the effects of polyphosphoric acid (PPA), styrene-butadiene rubber (SBR) and sulfur on the physical properties, dynamic rheological properties, the high-temperature storage stabilities, the morphologies and the internal structures of asphalts were studied, respectively.