Search

Resin‐infiltration technique has been employed as a versatile method to improve nanofiller dispersion in matrix. In this article, fabrication of polyvinyl chloride (PVC)/p‐phenylenediamine (PPD)/functional graphite (F‐G) and PVC/F‐G composite paper have been reported through resin‐infiltration techniques. Synthesis and characterization of PVC/PPD/F‐G and PVC/F‐G composite papers for enhanced structural, morphological, thermal, hardness, wettability, and conductivity properties have been studied. Moreover, the effect of increasing amount of F‐G and PPD/F‐G nanofiller on composite paper properties was scrutinized and compared. Transmission electron microscopy and scanning electron microscopy depicted better graphite nanofiller dispersion in PVC matrix and network formation in PVC/PPD/F‐G composite paper. Maximum degradation temperature (Tmax) of PVC/PPD/F‐G 0.08 composite paper (517°C) was found higher than PVC/F‐G 0.08 composite paper (484°C). Dynamic contact angle analysis shows that the PVC/PPD/F‐G and PVC/F‐G composite papers have better surface wettability than neat PVC. PVC/PDD/F‐G 0.1 and PVC/F‐G 0.1 composite papers possess high microhardness values up to 39.67 and 32.76 Hv, respectively. Electrical conductivity of 8.97 × 10−3 and 5.89 × 10−3 S m−1 was observed for 0.08 wt% PPD/F‐G and F‐G loaded samples. POLYM. COMPOS., 39:4176–4187, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The electrochemical performance of lithium-ion batteries are affected by the anode materials. SnO is an important anode material due to its high theoretical specific capacity of about 783 mAh/g for next-generation lithium-ion batteries with a higher energy density. In this work, we combined the electrochemical advantages of graphene and TiO, and the Ti-doped composites of SnO/reduced graphene oxide as the anode materials were fabricated by a hydrothermal method. To analyze the structure and electrochemical properties, a series of characterizations including X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical measurements were performed. The results confirmed that Ti atoms effectively replaced Sn atoms, improving the long-term cycling stability, which exhibited a superior rate capability and maintained a high discharge capacity around 500 mAh/g after 200 cycles. [ABSTRACT FROM AUTHOR]

We present the first report on the extraction and structure of cellulose nanocrystals (CNCs) from waste kelp residue after alginate extraction. CNCs were successfully prepared from this species of brown algae residue at a 9.6 % yield by a series of procedures involving swelling treatment, residual alginate isolation, ultrasonic smashing, bleaching, delignification and sulfuric acid hydrolysis. The high aspect ratio of CNCs with a crystallinity index of 74.5 % was observed by X-ray diffraction, transmission electronic microscopy and atomic force microscopy. Results clearly indicated that the selected multiple-step procedures provided the possibility of chemical cleavage of non-cellulosic components of kelp structure and then of fabrication of CNC nanowhiskers. Interestingly, stable aqueous and ethanol colloidal suspensions were determined by zeta potential measurement. In addition, porous CNC aerogels with interconnected fibrillar open networks were finally prepared using a freeze-drying process. This work mainly aimed to reuse industrial deaglinate kelp residue, giving it a useful application and preventing its role as an environmental pollutant. [ABSTRACT FROM AUTHOR]

In this paper, monodispersed ZnO microspheres in sizes from 50 to 200 nm were synthesized with a developed two-step method. In the primary reaction, ethanol suspension of ZnO nanoparticles was prepared, and monodispersed ZnO microspheres were synthesized in the secondary reaction by adding the ZnO nanoparticles suspension into the reaction solution. Diameter of the ZnO microspheres could be controlled by varying the volume of QDs suspension added. The transmission microscopy images and X-ray diffraction patterns of the ZnO microspheres showed that no matter their diameters, the ZnO microspheres were formed by aggregation of well crystallized ZnO nanoparticles. The polydispersity indexes (PDI) of ZnO microspheres were detected. It is found that PDI values of the microspheres were all less than 1.0, suggesting the monodispersity of the ZnO microspheres. The PDI value was only 0.16 when the diameter of the ZnO microspheres was 150 nm. [ABSTRACT FROM AUTHOR]

Abstract: Stable, neutral TiO2 hydrosols were prepared using TiCl4 as titanium source, HNO3 as peptizing agent, and SiO2 as stabilizer. Based on XRD, TEM, and FTIR measurements, the TiO2 was rodlike anatase crystallite with a major axis of 15–25 nm and a minor axis of 5 nm. Tih name="sbnd" />Si bonds were formed, which suppressed the TiO2 grain growth and stabilized the TiO2 hydrosols. The isoelectric points (IEP) of the series hydrosols were 3.1–4.7 pH values and the absolute zeta potentials of the SiO2-modified TiO2 hydrosols were much higher than 50.0 mV under neutral conditions. Methylene blue and reactive brilliant red X-3B were taken as the simulated pollutants to study the adsorption and photocatalytic properties of the obtained hydrosols. The results suggested that the prepared hydrosols had strong adsorption capacity for cationic pollutants rather than anionic ones, and high photodegradation rate of both cationic and anionic pollutants. [Copyright &y& Elsevier]

Abstract: Multiwall carbon nanotubes (MWCNTs) were prepared by catalytic decomposition of methane at 680–700°C, using nickel oxide-silica binary aerogels as the catalyst. The morphological structure of MWCNTs was investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The results revealed that MWCNTs had a diameter of 40–60nm, with high quality and high length/diameter ratio, and some metal catalyst particles were encapsulated at the tip of nanotubes. Using MWCNTs as the electrodes of flow-through capacitor (FTC), desalination performance was investigated. The results showed that modification methods had great effect on desalination performance of MWCNTs. The removal amount of NaCl was generally dependent on the surface area and pore volume of MWCNTs. After modification in diluted HNO3 solution with ultrasonic and then ball milling, the metal catalyst particles at the tip of nanotubes disappeared, the nanotube length became short, the cap at the tip of nanotubes was opened, the internal surface area could be effectively used, leading to increasing the specific surface area and pore volume for MWCNTs, and thus, the desalination performance thereof was the best of all. [Copyright &y& Elsevier]

Abstract: ZnO nanocrystallites were synthesized with the aids of NaNO3–KNO3 eutectic (45:55 wt.%) instead of any organic additives. X-ray powder diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM) were conducted. The characterization results indicated that the NaNO3–KNO3 eutectic, which acted as solvent medium, was in favor of the formation of homogeneous hexagonal ZnO nanocrystals. [Copyright &y& Elsevier]

Abstract: TiF4 and Ti(OEt)4 were used as titanium source to prepare Ti-containing MCM-48 by hydrothermal method, respectively. The products were characterized by X-ray diffraction (XRD), N2 adsorption–desorption, UV–visible absorption spectra and X-ray absorption near edge structure (XANES). The analysis results indicated that the types of titanium sources have great effects on the formation of Ti-MCM-48. Using TiF4 as precursor, Ti-containing silica with cubic mesoporous structure can be synthesized simply and quickly. The UV–visible absorption spectra and Ti K-edge XANES spectra confirmed that the isolated tetrahedrally-coordinated titanium oxide moieties were highly dispersed in the framework of MCM-48 by using TiF4 as titanium source. [Copyright &y& Elsevier]

Abstract: A series of Ce1−x Cu x O2 nanocomposite catalysts with various copper contents were synthesized by a simple hydrothermal method at low temperature without any surfactants, using mixed solutions of Cu(II) and Ce(III) nitrates as metal sources. These bimetal oxide nanocomposites were characterized by means of XRD, TEM, HRTEM, EDS, N2 adsorption, H2-TPR and XPS. The influence of Cu loading (5–25mol%) and calcination temperature on the surface area, particle size and catalytic behavior of the nanocomposites have been discussed. The catalytic activity of Ce1−x Cu x O2 nanocomposites was investigated using the test of CO oxidation reaction. The optimized performance was achieved for the Ce0.80Cu0.20O2 nanocomposite catalyst, which exhibited superior reaction rate of 11.2×10−4 mmolg−1 s−1 and high turnover frequency of 7.53×10−2 s−1 (1% CO balanced with air at a rate of 40mLmin−1, at 90°C). No obvious deactivation was observed after six times of catalytic reactions for Ce0.80Cu0.20O2 nanocomposite catalyst. [Copyright &y& Elsevier]

Abstract: The Sn4+ doped anatase TiO2 nanocrystals with various amounts of dopant Sn4+ ions were prepared from peroxo-metal-complex precursor by solvothermal method and characterized by XRD, TEM, HRTEM, XPS, ICP-AES and UV–vis spectrophotometer. The experimental results indicated that the dopant Sn4+ substituted Ti4+ in the lattice of TiO2, which reflected in the lattice expansion in both a- and c-direction and change of the binding energy. All the Sn4+ doped TiO2 nanocrystal samples appeared to be anatase evenly with dopant level up to 10mol%. The effect of dopant Sn4+ ions and reaction solvents on physicochemical properties of the obtained Sn4+ doped anatase TiO2 nanocrystals had been discussed. In addition, the growth mechanism and microstructure evolution of Sn4+ doped anatase TiO2 nanocrystals had been suggested. The photocatalytic activity of the Sn4+ doped anatase TiO2 nanocrystals was tested by the degradation of phenol. Compared with the undoped TiO2 sample, the enhanced photocatalytic activity of the Sn4+ doped anatase TiO2 nanocrystals could be attributed to modification of the optical properties and surface state by doping the optimum concentration of Sn4+ ions. [Copyright &y& Elsevier]

Abstract: A simple method to prepare Cu2+ doped mesoporous TiO2 with improved visible sensitive photocatalytic activity is reported. The mesoporous samples were characterized by low angle and wide angle X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption–desorption, X-ray photoelectron spectra (XPS) and UV–visible absorbance spectroscopy. The degradation of methylene blue under visible light irradiation was investigated to evaluate the photocatalytic activity of these materials. Analytical results demonstrate that Cu2+ doping amount is crucial to affect the photocatalytic ability of the mesoporous titania. Among the samples, 0.05at.% Cu2+ doped mesoporous TiO2 exhibits the highest photocatalytic activity. [Copyright &y& Elsevier]

Abstract: Fluorine-doped tin dioxide (FTO) nanocrystals were prepared with a sol–gel process followed by a hydrothermal treatment using SnCl4 and NH4F as SnO2 and fluorine dopant, respectively. The nanostructure and composition were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), zeta potential analysis, electrochemical measurement technology and X-ray photoelectron spectroscopy (XPS) respectively. The diameter of the fluorine doped SnO2 nanocrystal in rutile-type structure is about 10nm. Compared to the pure SnO2 nanocrystals, the fluorine doped SnO2 nanocrystals can be dispersed homogeneously in H2O, forming transparent sol with high stability. The powder of fluorine doped SnO2 nanocrystals could be obtained by removing the solvent, and the electrical resistivity properties were measured by a four-point probe measurement. The results show that sheet resistances (Rs) of fluorine doped SnO2 decrease with the increasing NH4F/Sn molar ratio in the range from 0 to 2. However, further increase of NH4F/Sn molar ratio from 2 to 5 leads to higher sheet resistance. The F/Sn molar ratio of fluorine doped SnO2 measured by XPS is about 0.18 when NH4F/Sn molar ratio is equal to 2, and the sheet resistance of fluorine doped SnO2 powder is 110Ω/□. [Copyright &y& Elsevier]

Abstract: Monodisperse Y2O3:Eu3+ nanospheres have been successfully synthesized by a low-temperature reflux method assisted by cetyltrimethyl ammonium bromide (CTAB). The products were characterized by X-ray diffraction spectroscopy, transmission electron microscopy, scanning electron microscopy, Fourier-transform infrared spectrophotometer, thermogravimetric and differential thermal analysis, and X-ray photoelectron spectroscopy. It is demonstrated that the size of Y2O3:Eu3+ nanospheres can be controlled from 80 to 140nm with narrow size distribution by adjusting the amount of CTAB. A possible formation mechanism of Y2O3:Eu3+ nanospheres has been proposed. The photoluminescence analysis shows that Y2O3:Eu3+ nanospheres obtained have a strong red emission peak of Eu3+ ions at around 611nm, due to the 5D0 → 7F2 forced electric dipole transition of Eu3+ ions. It is found that the photoluminescence performance of the obtained Y2O3:Eu3+ nanospheres is stronger than that of the Y2O3:Eu3+ nanorods synthesized by a traditional hydrothermal route. [Copyright &y& Elsevier]

Abstract: Carbon nanotube (CNT)/ceria core–shell nanowires were prepared facilely on a large scale under the boiling reflux of ethylene glycol. The composites are characterized by transmission electron microscopy, X-ray diffraction as well as Fourier transformed infrared spectra. It is found that the entire outer surface of CNTs is fully sheathed with a dense layer of uniform nanosized CeO2, and that the thickness of the coating sheath can be readily manipulated by tuning the molar ratio of ceria to CNTs. Finally, a possible formation mechanism has been suggested as follows: with the high reaction temperature, ethylene glycol is partially converted to oxalic acid, and the surface hydroxyl groups of CeO2 tiny particles react with oxalic acid to form the polymer-like inorganic–organic compounds. Subsequently, in view of the low-energy point, the polymer-like inorganic–organic compounds are coated on the surface of CNTs, and thus CNTs/ceria core–shell composites are obtained. [Copyright &y& Elsevier]

Abstract: In this work, the nanocomposites, carbon nanotubes (CNTs) coated with nanosized ceria, were prepared by a facile solvothermal method. The obtained nanocomposites have a dense overlayer which is made of nanoparticles with the diameter of ∼10nm. Ceria nanotubes with a porous and hollow structure were fabricated by the removal of CNTs, which possess high surface area and remarkable thermal stability. The products were characterized by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The parameters affecting the formation of CeO2 nanotubes were discussed in details. The key steps involved in the formation of the CeO2 nanotubes are solvothermal modifications of CNTs and controlled calcinations. CeO2 nanotubes have an excellent catalytic performance for the CO oxidation. The remains of the templates in the CeO2 nanotubes are considered to play an important part in the enhanced catalytic activity for the formation of CeO2− x C x . [Copyright &y& Elsevier]

Abstract: In this work, CeO2 nanoplates were synthesized by a hydrothermal reaction assisted by hexadecyltrimethylammonium bromide (CTAB) at 100–160°C. The size of nanoplates was around 40nm. Further experiment showed that the controlled conversion of nanoplates into nanotubes, and nanorods can be realized by changing the reaction time, temperature, and CTAB/Ce3+ ratio value. X-ray diffraction (XRD), transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET) nitrogen adsorption–desorption measurements were employed to characterize the samples. The CO oxidation properties of nanorods, nanoplates, and nanotubes were investigated. An enhanced catalytic activity has been found for CO oxidation by using CeO2 nanoplates as compared with CeO2 nanotubes and nanorods, and the crystal surfaces (100) of CeO2 nanoplates were considered to play an important role in determining their catalytic oxidation properties. [Copyright &y& Elsevier]

This work reports the synthesis of highly dispersed Mn-Co/RGO via a novel light driven approach having attributes of being green, facile and controllable, for the catalytic degradation of methylene blue (MB) in the presence of H 2 O 2 . The prepared catalysts were characterized by TEM, EDS, IR, XRD and XPS techniques. A synergy between RGO and Mn-Co species existed where the former helped in adsorption of MB and stabilization and dispersion of Mn and Co on the surface while the latter improved H 2 O 2 utilization by generating HO , which enhanced the decomposition of MB. It was found that O 2 •− and O 2 •− /HO • were the main radicals in post Mn/RGO and Mn-Co/RGO treatment, respectively. Both O 2 •− and HO • oxidized MB with a faster rate by the former, but its side reaction can hinder effective utilization of H 2 O 2 while the reverse was true for the latter. A 50 mg/L MB was completely decomposed within 15 min using 10 mg of Mn-Co/RGO. Thus the synergistic effect of RGO by adsorption MB and Co species avoiding the side reaction led to enhanced rate of MB decomposition. [ABSTRACT FROM AUTHOR]

Abstract: At ambient pressure, metastable corundum-type In2O3 nanocrystals were successfully synthesized with ZnCl2 molten salt assisted calcination above 500°C. The products were characterized by X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy and photoluminescence spectroscopy. For the first time, we observed the formation of h-In2O3 with the aid of inorganic salt. The results show that ZnCl2 salt has significant effects on the formation of h-In2O3, which acted not only as a molten medium but also a mineralizer for the induced corundum phase. The approach requires neither complex apparatus and sophisticated procedures nor any organic additives during the reaction. The photoluminescence properties of In2O3 nanocrystals were also investigated. [Copyright &y& Elsevier]

Abstract: CeO2 hollow nanobeads have been synthesized facilely using carbon nanotubes as templates by means of a solvothermal treatment combined with controlled calcinations. The properties of CeO2 hollow nanobeads were characterized by TEM, EDS, XRD and XPS. The obtained CeO2 hollow nanobeads with polycrystalline face-centered cubic phase have a uniform morphology ranging from 150 to 200nm in outer diameter and 40 to 60nm in inner diameter. A possible formation mechanism has been suggested to explain the formation of CeO2 hollow nanobeads. It is found that CeO2 hollow nanobeads have an excellent catalytic performance for the CO oxidation. [Copyright &y& Elsevier]

Abstract: Bi2WO6 multilayer films have been fabricated successfully by a layer-by-layer (LbL) technique from Bi2WO6 nanoplates, which show higher visible-light photoactivity (λ>420nm) than that of Bi2WO6 nanoplate powders and P25 TiO2 films. The films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and UV–visible absorption spectroscopy. Photocatalytic activities of the films were evaluated by the rhodamine B (RhB) decomposition under UV and visible-light irradiation. Thickness and photoactivity of the film can be modified easily by changing the deposition cycles. Bi2WO6 films have the spectral selectivity of the photocatalytic degradation of RhB. Under the wavelength greater than 300nm, the RhB molecules tend to be transformed to rhodamine over Bi2WO6 films selectively. However, in the case of shorter wavelength (λ=254nm) light irradiation, the RhB molecules can be photodegraded completely. [Copyright &y& Elsevier]

Abstract: MoS2 nanolamellers were synthesized by a one-step oxidation–reduction reaction in solution, in which the (NH4)2MoS4 and H2C2O4·2H2O were used as reactants and then calcined at 800°C under N2 for 1h. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The diameter and nanoplate thickness of the obtained MoS2 nanolamellers were approximately 80nm and 20–30nm, respectively. These novel structures of nanolamellers had potential applications in solid lubricants. [Copyright &y& Elsevier]