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Mass Production of High-Purity Semiconducting Carbon Nanotubes by Hydrochloric Acid-assisted Gel Chromatography
摘要： Mass production of high-purity semiconducting single-wall carbon nanotubes (s-SWCNTs) is critical for their application in the electronic and optoelectronic devices. Here we reported a method for the high-efficiency separation of high-purity s-SWCNTs with the acid-assisted gel chromatography, in which hydrochloric acid (HCl) was used to selectively oxidize metallic SWCNTs (m-SWCNTs) and enhance the difference in the interaction of metallic and semiconducting nanotubes with gel. Specifically, the concentration of HCl in the eluent was gradually increased to elute the carbon nanotubes adsorbed in the gel column step by step. The m-SWCNTs were firstly eluted at a low HCl concentration, and high-purity s-SWCNTs were selectively eluted at a higher HCl concentration. The final residues containing a relatively high content of m-SWCNTs and amorphous carbon impurities were left in the gel columns. Optical and electrical characterizations confirmed that the purity of the s-SWCNTs extracted from various raw SWCNT materials, especially CoMoCAT (7, 6), was improved greatly. Moreover, multiple single-chirality SWCNTs were firstly separated from the purified semiconducting CoMoCAT (7, 6) nanotubes. Our present work provides a simple and controllable way for the mass separation of high-purity s-SWCNTs and single-chirality species, which would accelerate their application in the field of electronics, optoelectronics and bio-imaging.
关键词： hydrochloric acid,separation,gel chromatography,Semiconducting carbon nanotubes,single-chirality
更新于2025-09-23 15:23:52
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A novel bis(dihydroxypropyl) viologen-based all-in-one electrochromic device with high cycling stability and coloration efficiency
摘要： Electrochromism and related devices have been studied for a few decades from both fundamental and technological point of view. At the present stage, screening electrochromic materials with excellent properties is still an interesting job. In our previous work, we have demonstrated that hydroxyalkyl viologens could exhibit satisfying electrochromic behavior. Further, in this paper, the bis(dihydroxyalkyl) viologen, (1,1‘-bis(2,3-dihydroxypropyl) 4,4‘-bipyridine derivative dichloride, DHPV2t 2Cl-, was synthesized and incorporated as an electrochromic chromophore in the all-in-one electrochromic devices (ECDs) on the basis of poly (vinyl butyal) (PVB)-carbonate and po?y (vinyl alcohol) (PVA)-borax gel electrolytes, respectively. It was found that DHPV2t 2Cl- in PVB-based gel ECDs underwent reversible switching between transparent and deep blue hue, whereas the clear color changes from colorlessness to amaranth in PVA-borax-based ones upon the potential ranges from 0 V to (cid:2)1.0 V. For PVB-based gel ECD, spectroelectrochemical studies demonstrated that it only needs a low coloration voltage down to (cid:2)0.6 V, and exhibites high coloration ef?ciency (h) up to 301 cm2/C. The optical contrast of it only reduces by 1% after consecutive operation for 10000 cycles between (cid:2)1.0 V and 0 V, demonstrating an excellent cycling stability of this kind of device. The ECD based on PVA-borax gel modi?ed with glycerol shows burgundy, and good electrochromic performance. It is interesting to note that a relatively large-area PVB-based gel electrochromic devices up to 168 cm2 was realized, the driving voltage and response time being (cid:2)1.5 V and 12 s, respectively, for blue-violet coloration state. The advantages of electrochromic properties exhibited by 1,1‘-bis(2,3-dihydroxypropyl) viologen dichloride over those reported can be regarded as a pronounced improvement for organic electrochromic materials, and are expected to set the stage for novel electrochromic devices such as smart window and display applications and so forth.
关键词： Coloration ef?ciency,Electrochromic (EC) gel,Stability,Viologen,Electrochromic devices (ECD)
更新于2025-09-23 15:23:52
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Mg dependent Sunlight photocatalytic performance of Nickel ferrite synthesized by a green sol-gel route
摘要： We report an environmentally friendly synthetic strategy to synthesize new nickel ferrite and Mg doped nickel ferrite photocatalysts under modified green sol-gel route in which Aloe Vera gel acts as a natural template. The crystalline phase, surface morphology and size of the prepared photocatalysts were characterized by PXRD, SEM, TEM and HRTEM analysis. The energy band gap of the nanoparticles (NPs) can be tuned in the range of 2.55–2.34 eV by varying the dopant concentration. The photoluminescence analysis indicates that the present NPs are an effective white component in display applications. These synthesized NPs were used for photocatalytic decomposition of recalcitrant pollutants in aqueous media under Sunlight irradiation. When compared to pure, NiFe2O4: Mg2+ (5 mol %), the NiFe2O4: Mg2+ (1mol %) exhibits the highest photocatalytic efficiency for the decomposition of recalcitrant pollutants than that of commercial P25.This enhancement in photocatalytic performance can be mainly attributed to the balance between the parameters, crystallanity,band gap, morphology, crystallite size, defects, dopant amount and combined facets of photocatalysis It opens new window to use this simple greener route to synthesize bi-functional character NPs in the area of photocatalysis particularly waste water treatment and display applications.
关键词： Photo-Fenton catalytic performance,Photoluminescence,Green Sol-gel route,NiFe2O4:Mg2+NPs
更新于2025-09-23 15:23:52
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Spherical LiZnBO3: Structural, Optical and Electrochemical Properties
摘要： Spherical – LiZnBO3 material is synthesized by sol-gel technique and the structural, optical, and electrochemical properties of LiZnBO3 are analyzed. X-ray diffraction result reveals the formation of α-LiZnBO3. Scanning electron microscope and transmission electron microscope image shows spherical morphology and the size of particle is approximetly 80 nm. Absorbance spectra reveal the characteristics band edge of LiZnBO3 is noticed around 210 nm and the band gap is found to be 5.57 eV. Defect-induced intrinsic luminescence is observed in the LiZnBO3 material. The calculated electrical conductivity of LiZnBO3 is 9.52 x 10-9 S/cm. Charge–discharge measurement indicates that the sol-gel synthesized LiZnBO3 delivers a first charge-capacity of 78.82 mAh g-1 at C/10 rate and yields the discharge capacity of 7 mAh g-1 at the 10th cycle. An improved capacity is expected to be reached by further reduction in particle size, doping and conductive carbon coating.
关键词： Sol-gel,Spherical,Optical and electrochemical properties,LiZnBO3
更新于2025-09-23 15:23:52
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Acetic anhydride as oxygen donor in the non-hydrolytic sol-gel synthesis of mesoporous TiO2 with high electrochemical lithium storage performances
摘要： An original, halide-free non-hydrolytic sol-gel route to mesoporous anatase TiO2 with hierarchical porosity and high specific surface area is reported. This route is based on the reaction at 200 °C of titanium (IV) isopropoxide with acetic anhydride, in the absence of a catalyst or of a solvent. NMR studies indicated that this method provides an efficient, truly non-hydrolytic and aprotic route to TiO2. Formation of the oxide involves acetoxylation and condensation successive reactions, both with ester elimination. The resulting TiO2 materials were nanocrystalline, even before calcination. Small (≈10 nm) anatase nanocrystals spontaneously aggregated to form mesoporous micron sized particles with high specific surface area (260 m2 g-1 before calcination). Evaluation of the lithium storage performances showed a high reversible specific capacity, particularly for the non-calcined sample with the highest specific surface area favoring pseudo-capacitive storage: 253 mAh g-1 at 0.1C and 218 mAh g-1 at 1C (C = 336 mA g-1). This sample also showed good cyclability (>92% retention after 200 cycles at 336 mA g-1) with a high coulombic efficiency (99.8 %). Synthesis in the presence of a solvent (toluene or squalane) offers the possibility to tune the morphology and texture of the TiO2 nanomaterials.
关键词： anatase,mesoporous,acetic anhydride route,non-hydrolytic sol-gel,Li-ion batteries
更新于2025-09-23 15:23:52
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Improvement of nickel nanocomposite coatings by combining zinc-doped TiO2 nanoparticles
摘要： Pure nickel and compound of nickel coatings (Ni-TiO2 and Ni-Zn/TiO2) were coated on the steel material using Watts bath with the electrodeposition conditions. Effect of the nanoparticle type and current density on the coating structure, surface morphology of the coating, hardness of the coating, and the corrosion properties of the coatings are presented. Phase and elemental analysis of the coatings were carried out by XRD and EDS techniques, respectively. SEM was used to investigate the surface morphology of the coatings, and Vickers microhardness values were measured to determine the hardness variation of the coatings. NaCl solution (3.5 wt%) was used to evaluate the corrosion properties of the coatings by the potentiodynamic polarization tests. Corrosion current density of 2.890 μA/cm2 for pure nickel coating was improved to 0.379 μA/cm2 by the coating of Zn-doped TiO2 nanoparticles at the 7A/dm2 current density. Microhardness of the Zn-doped TiO2 coating was improved compared to the pure Ni coating.
关键词： Sol-gel processes,Metal matrix composites,Nanoparticles,Composite coatings
更新于2025-09-23 15:23:52
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Preparation of 3D flower-like Fe-Bi2O3 nanocomposite and its photocatalytic performance under visible light irradiation
摘要： The objective followed by this research is the synthesis of 3D ?ower-like Fe-Bi2O3 and the study of its capability for the degradation of Rhodamine B (RhB) under visible light irradiation (λ > 400 nm). Samples were obtained by a simple sol–gel method at room temperature. The as-prepared Fe-Bi2O3 exhibited excellent photocatalytic performance under the visible light due to its relatively narrow band gap energy (2.83 eV). The photocatalytic activity was carefully evaluated with respect to RhB photodegradation in di?erent conditions such as light source and reaction time. The experimental results showed that the degradation rate of 3D ?ower-like Fe-Bi2O3 is up to 82% under visible light irradiation, when EtOH/H2O volume ratio and Bi/Fe molar ratio are 7:3 and 20:1, respectively.
关键词： Nanocomposites,Fe-Bi2O3,Sol-gel,Photocatalytic activity
更新于2025-09-23 15:23:52
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Magnetization and magnetic resonance in sol-gel derived polycrystalline BiFeO3 film
摘要： The structure and magnetic properties of polycrystalline BiFeO3 films grown on glass substrate using Sol-Gel technique have been investigated. X-ray diffraction (XRD) analysis revealed the average grain size of about 21 nm. The root mean square (RMS) surface roughness of about 50 nm has been obtained for the film by using scanning electron microscope (SEM) technique. Ferromagnetic resonance (FMR) studies showed the presence of macroscopic ferromagnetic magnetization and uniaxial out-of-plane magnetic anisotropy. The temperature dependences of the magnetization of BiFeO3 films registered in zero field cooling (ZFC) and field cooling (FC) regimes revealed a spin glass state. The average magnetic crystallite sizes obtained from the magnetizations studies coincide with the values revealed from the structural studies.
关键词： sol-gel technique,magnetic properties,magnetic materials,multiferroics
更新于2025-09-23 15:23:52
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Composite BNT-BT0.08/CoFe2O4 with core-shell nanostructure for piezoelectric and ferromagnetic applications
摘要： In this work, we report on the synthesis and characterization of BNT-BT0.08/CoFe2O4 biphasic composite with core-shell structure. This artificial core (BNT-BT0.08)/shell (CoFe2O4) heterostructure was prepared by sol-gel method and the resulting composite was characterized in term of microstructure, dielectric, piezoelectric and magnetic properties. BNT-BT0.08/CoFe2O4 sintered ceramic shows high permittivity (ε′ ≥ 30) and high dielectric losses (tan δ ≥ 10) in the low frequency range (ν ≤ 104 Hz), remnant polarization (Pr) of ～7.7 μC/cm2 and, remanent magnetization (Mr) of 24 emu/g at 5 K and of 14 emu/g, at room temperature. The present study reveals that the ferroelectric, piezoelectric and magnetic properties of this new architectured composite depend on the amount of each component and, can be tailored by adjusting their synthesis conditions. BNT-BT0.08/CoFe2O4 core-shell material investigated in this work provides a novel way to exploit new applications for the multifunctional composite, such as piezoelectric sensor, magnetoelectronic sensors and data storage devices.
关键词： Sol-gel processes,Composite core-shell,((Bi0.5Na0.5)0.92Ba0.08TiO3),Cobalt ferrite (CoFe2O4),Lead-free piezoelectric
更新于2025-09-23 15:23:52
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Combustion synthesis of nontoxic water-induced InYO thin film and application in thin film transistor
摘要： In the work, novel indium yttrium oxide (InYO) thin ?lms are prepared by an environmentally friendly aqueous solution process. Y element is added to suppress the generation of oxygen vacancies. The e?ect of Y doping on the performance and stability of nontoxic water-induced InYO thin ?lm transistors (TFTs) is ?rstly examined. With the increase of Y doping contents, o?-state current is decreased and mobility decreases from 15.8 to 11.7 cm2 V?1 s?1. Furthermore, the stability under positive bias stress is also obviously improved. The device with 2 mol% Y element shows an optimized electrical performance and good stability, including mobility of 12.8 cm2/V s, threshold voltage of 1.4 V, subthreshold swing of 0.33 V/decade and threshold voltage shift of 2.31 V under positive voltage stress of 5 V for 10,000 s. The performance improvement is attributed to the decrease of oxygen vacancies and the decline of interface trap density by Y addition.
关键词： Thin ?lms,Amorphous materials,Electrical properties,Sol-gel chemistry
更新于2025-09-23 15:23:52