Yunling Li

Henan Institute of Science and Technology, Honanfu, Henan Sheng, China

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Publications (15)22.83 Total impact

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    ABSTRACT: Cu active nanoparticles (Cu ANPs) were synthesized in weakly acidic solution to preserve their catalytic activity. SiO2 capsules were designed to insulate Cu ANPs from oxidation. The weak interaction between SiO2 capsules and Cu ANPs ensured that the designed nanoparticles had good anti-oxidation property and potentially high activity. The increased anti-oxidation property with thicker SiO2 capsules (Cus3 > Cus2 > Cus1) and the order of reactivity to oxygen (Cus1 = Cus2 > Cus3) showed that Cu ANPs with SiO2 capsules (Cus2) of appropriate thickness would be the best for application. By using the samples to construct non-enzymatic sensors, the detected activity toward electro-catalytic oxidation of glucose confirmed this conclusion. Dehiscence of SiO2 capsules recovered the activity of the Cu ANPs in the catalytic ammonium perchlorate (AP) decomposition process. With the addition of 1.5% of Cu ANPs, the high temperature decomposition of AP decreased by 184.2 °C.
    J. Mater. Chem. A. 06/2013; 1(27):8029-8036.
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    ABSTRACT: A simple room temperature method was reported for the synthesis of CuO nanocrystals in aqueous solution through the sequence of Cu(2+) → Cu(OA)2 → Cu(OH)2 → Cu(OH)(2-)4 → CuO. Sodium oleate (SOA) was used as the surfactant and shape controller. The as-prepared samples were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible absorption spectroscopy (UV-vis) and differential thermal analysis (DTA). It can be seen that 1D Cu(OH)(2) nanowires were first obtained from Cu(OA)(2) and, at room temperature, converted into 2D CuO nanoleaves (CuO NLs) in a short time under a weakly basic environment. On prolonging the reaction time, the top part of these 2D nanoleaves branched and separated along the long axis to form 1D rod-like nano-CuO because of the assistance of SOA. A possible transformation mechanism of Cu(OH)(2) to CuO nanostructures at room temperature in aqueous solution is discussed. The transformation velocity can be controlled by changing the pH value of the system. The prepared CuO NLs were used to construct an enzyme-free glucose sensor. The detecting results showed that the designed sensor exhibited good amperometric responses towards glucose with good anti-interferent ability.
    Nanotechnology 03/2011; 22(11):115604. · 3.84 Impact Factor
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    ABSTRACT: Tungsten oxide hydrate (WO3·H2O) nanoplates and flower-like assemblies were successfully synthesized via a simple aqueous method. The effects of reaction parameters in solution on the preparation were studied. Nanoplates and nanoflowers can be selectively prepared by changing the amount of H2C2O4. In-situ assembly of nanoplates to nanoflowers was also proposed for the formation of assembled nanostructures. In addition, the reaction time and temperature have important effects on the sizes of the as-obtained samples. Crystal structure, morphology, and composition of final nanostructures were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Optical properties of the synthesized samples and the growth mechanism were studied by UV–vis detection. Degradation experiments of Rhodamine B (RhB) were also performed on samples of nanoplates and nanoflowers under visible light illumination. Nanoflower sample exhibited preferable photocatalytic property to nanoplate sample.
    Journal of Solid State Chemistry 01/2011; 184(7):1661-1665. · 2.04 Impact Factor
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    ABSTRACT: Mn3O4 nanocrystals were prepared by a simple aqueous precipitation method using Mn(CH3COO)2·4H2O and NaOH as precursors at low temperature of 30 °C. The as-prepared Mn3O4 nanocrystals were characterized by means of XRD, SEM, UV–vis and FT-IR analyses. Mn3O4 nanoparticles prepared at 30 °C extended octahedral, spherical and rod-like structures with the sizes in the range of 60–100 nm. The size and shape could be manipulated by reaction time. The as-prepared Mn3O4 was so sensitive to hydrochloric acid (HCl) that the sample color changed obviously from brown to black. Analyses on the HCl treated and untreated samples gave results that varied ratio of Mn2+, Mn3+ and Mn4+ in Mn3O4 crystals led to color changes of the samples. Optical properties of the samples were discussed via the UV–vis and FT-IR results.Graphical abstractResearch highlights▶ Octahedral Mn3O4 nanocrystals were prepared by a simple aqueous method. ▶ The size and shape were controlled by the reaction time. ▶ The reaction velocity can be manipulated by PEG and temperature. ▶ The oxide composition of Mn3O4 vaied with H/Mn ratios.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 01/2011; 374:42-47. · 2.11 Impact Factor
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    ABSTRACT: Low quality rice bran with high free fatty acid content was utilized to produce fatty acid ethyl ester (FAEE) via in situ method. The effects of extraction solvent, acid and alkaline catalysts on the yield rate, esterification rate and transesterification rate were studied. About 12% (wFAEE/wrice-bran) of FAEE was obtained when absolute ethanol was used as solvent to extract rice bran oil. The esterification rate and transesterification rate reached 98% and 83%, respectively. With the aid of petroleum ether, the yield rate of FAEE could be improved to 16% (wFAEE/wrice-bran), and the esterification rate and transesterification rate reached 99% and 86%. Hydrophobic CaCO3 nanorods were also synthesized as value-added byproduct. Based on the proposed method, the production process of FAEE could be simplified and the production cost could be reduced.
    Fuel. 01/2011; 90(2):592-597.
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    ABSTRACT: We report here a simple approach to the synthesis of highly dispersed Co3O4 nanocubes in higher yield by aqueous precipitation method at low temperatures (70–90 °C). The nanosized Co3O4 powders were directly achieved from Co(II) aqueous solution under alkaline and oxidizing conditions. TEM results indicate that the as-prepared Co3O4 has a cubic nanostructure with uniform size of about 20 nm and narrow size distribution. Powder X-ray diffraction (XRD) and infrared spectrum (IR) results show that the samples are Co3O4 in spinel structure. The objective Co3O4 nanocubes can be achieved in a wide range of experimental parameters, which can be preserved as stable suspension in distilled water or ethanol for several months with no obvious change. Appropriate reaction time and temperature should be controlled to get better crystallized Co3O4 nanocubes with perfect cubic appearance and good dispersibility. It is essential to achieve cubic-like Co3O4 particles by using ammonia as precipitator. The as-prepared Co3O4 nanocubes, combined with PbO2 as electrodes, extend improved electrocatalytic activities and decreased oxygen evolution potential in electrochemical reactions, so they can be used as potential electrode materials or electrocatalytic materials. This facile method for the synthesis of Co3O4 nanocubes is a simple and general process without any seed, catalyst, or template, thus it is promising for large-scale and low-cost production of Co3O4 with high-quality.
    Chemical Engineering Journal. 01/2011;
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    ABSTRACT: Rice husk is an abundant agricultural byproduct. In the present paper, research on consecutive preparation of d-xylose and superfine silica from rice husk is carried out. The optimum hydrolysis conditions of xylan in rice husk to d-xylose are as follows: the concentration of H(2)SO(4) is 4% (wt.%), the temperature is 130 degrees C, the ratio of rice husk mass (g) to H(2)SO(4) solution volume (ml) is 1:4 and the time is 2 h. The hydrolysis degree of xylan reaches 96.22% (wt.%). High purity (98.5%, wt.%) d-xylose is obtained from acid hydrolysis solution with the purification yield of 71.63% (wt.%). At the same time, the metal oxides in rice husk are efficiently dissolved by H(2)SO(4). Residuals from H(2)SO(4) pre-treatment are incinerated under 750 degrees C in stationary air for 15 min. Silica is obtained with the purity of 99.87% (wt.%). The superfine silica powder is obtained after ground and ultrasonic dispersion, with the diameter of 30-200 nm and specific surface 287.86 m(2)/g.
    Bioresource Technology 02/2010; 101(4):1263-7. · 5.04 Impact Factor
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    ABSTRACT: Low quality rice bran was used to produce fatty acid methyl ester (FAME) via in situ extraction, esterification and transesterification process. The effects of the acid and alkaline catalysts on the ester yield, esterification and transesterification process were studied. When 75 ml of absolute methanol, 150 ml of petroleum ether, 0.75 g of concentrated sulfuric acid and 0.71 g of sodium hydroxyl were used, 16.69% (wFAME/wrice bran) of FAME was obtained. The esterification rate and the transesterification rate reached 98.83% and 80.47%. Based on the proposed route, the production process of FAME (biodiesel) could be simplified and the production cost could be reduced.
    Fuel. 01/2010;
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    ABSTRACT: In this work, we report a mild chemical procedure to synthesize rice ear-like cobalt microstructures using hydrazine hydrate as the reductive agent. The as-obtained products were characterized by X-ray diffraction, scanning electron microscopy, and vibrating sample magnetometry. The results show that the samples are hexagonal-close-packed (hcp) Co dendritic structures composed of a pronounced trunk and multiple ears. The length of the main trunk is tens of micrometers, and that of each ear is 3–5 μm with a width of about 1 μm. It was found that the chain length of surfactant PEG as directing agent drastically influenced the morphologies of the produced cobalt crystals. The morphologies of samples can be manipulated from cauliflower to flower and then to rice ear-like structures only by choosing PEG of different molecular weight as surfactant. These microstructures exhibited a ferromagnetic behavior at 300 K and might have potential applications in microdevices and other related magnetic devices.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 01/2010; 356:156-161. · 2.11 Impact Factor
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    ABSTRACT: An aqueous synthesis approach has been developed for shape control of Bi nanostructures. Here, we demonstrate a work on the selective preparation of bismuth nanospheres and nanorods reduced by hydrazine hydrate in the presence of organic molecules as controlling agent. Bismuth nanotubes were also obtained by manipulating the reaction parameters in the system. On controlling the size and dispersibility of the project powders, Bi nanospheres with average diameter of 100 nm, Bi nanorods with length of 50 nm or 200 nm, and Bi nanotubes with length of 100–200 nm have been successfully synthesized. We also discussed the possible growth mechanisms of bismuth nanostructures by studying the influences of experimental parameters. The optical absorption spectra of the shape-controlled bismuth nanostructures show strong absorptions in the range of 200–400 nm. These Bi nanostructures are expected to find potential applications in a variety of areas due to their optical characteristics.
    Colloids and Surfaces A: Physicochemical and Engineering Aspects. 01/2010;
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    ABSTRACT: Stabilized bismuth nanoparticles have been prepared by reducing bismuth chloride with hydrazine hydrate in the presence of sodium oleate under a facile water-based process. The obtained samples are investigated by X-ray diffraction, transmission electron microscopy (TEM) and differential thermal analysis and thermogravimetry (DTA/TG). The present results indicate that the bismuth nanoparticles are spherical, small diameter and in a high purity. In addition, measurement of water contact angle indicates that Bi samples are hydrophobic, which gives defense to samples from further oxidation, samples are steady in 6 months without obvious oxidation.
    Materials Research Bulletin. 01/2009; 44(1):220-223.
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    ABSTRACT: We report here a simple approach to the synthesis of Cu2O/TiO2 core-shell nanocomposites with uniform octahedral structure in solution phase. First, fresh synthesized Cu2O octahedra were used as precursor, and butyl titanate (Ti(OBu)4) diluted by ethanol was preliminary hydrolyzed by the water adsorbed on the surface of Cu2O, so a very thin TiO2 condensed on the Cu2O surfaces. Then, when a mixture of water and ethanol was dropped into the reaction system, the Ti(OBu)4 would further hydrolyze and condense around the Cu2O to form TiO2, so octahedral Cu2O/TiO2 core-shell composites with uniform and compact TiO2 shells were obtained. This method is suitable for the formation of uniform integrated TiO2 shells and their thickness can be controlled by adjusting the ratio of water/ethanol (W/E). According to the surface photovoltage spectroscopy of the Cu2O/TiO2 composites, we think the material would have a potential application in photocatalysis and photoelectric transition.
    Colloids and Surfaces A: Physicochemical and Engineering Aspects. 01/2009;
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    ABSTRACT: Cobalt microspheres constructed by the assembly of nanoplatelets have been synthesized by a wet chemical reductive procedure at room temperature with the help of glycerin and citric acid and without additional surfactants. The size of the microspheres is about 2–5 μm and that of the nanoplatelets assembled the microspheres is tens of nanometers in thickness. In this synthetic system, cobalt acetate was employed as Co source, sodium hydroxide was used to manipulate the pH value of the reaction system, and hydrazine hydrate was used as a reducing agent. A series of experiments were performed with different amounts of glycerin, from 0.5 mL to 4 mL, the results reveal that the formation of cobalt microspheres is assisted by glycerin. The shape, structure, and magnetic properties of the final products were investigated by XRD, SEM and VSM. This kind of Co nanostructures shows a ferromagnetic behavior at room temperature with enhanced coercivity, and has potential uses in magnetic recording devices and other related nanodevices. A possible mechanism for the formation of microspheres is proposed.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 01/2009; 336:41-45. · 2.11 Impact Factor
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    ABSTRACT: One-dimensional hydrophobic ZnO nanocrystals were successfully prepared via a one-step process through a direct precipitation reaction in aqueous solutions of ZnSO4 and NaOH with self-prepared octadecyl dihydrogen phosphate (C18H37OPO3H2, ODP) as a surface functionalizing reagent. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results showed that the obtained ZnO particles were one-dimensional (1D) with hexagonal crystal structure. Measurements of relative contact angle and active ratio indicated that the obtained 1D ZnO nanocrystals were hydrophobic. The results of Fourier transform infrared spectroscopy (FT-IR) spectrum and X-ray photoelectron spectroscopy (XPS) clearly showed the formation of interfacial chemical bonds between ZnO and ODP. Furthermore, from the results of TGA test, it was confirmed that a certain amount of organic components existed in the 1D ZnO nanocrystals. These results suggested that the formed organics were bonded onto the surface of 1D ZnO nanocrystals during the reaction process, besides, the organics resulted in the perfect compatibility of obtained ODP functionalized ZnO particles with common organic reagents like ethanol, cyclohexane, and acetone. The influences of ODP on the size of the obtained ZnO particles and the mechanism of surface hydrophobic functionalization by ODP were presented.
    Chemical Engineering Journal 06/2008; 139(3):642-648. · 3.47 Impact Factor
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    ABSTRACT: Cu nanostructures with different shapes were synthesized via a simple reduction approach from CuO nanoleaves at room temperature. The purity and morphology of samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements. By changing the dosage of reducing agent, Cu flowers and Cu octahedral cages were obtained successfully. The growth mechanism of morphology evolvement to different shaped Cu nanostructures is discussed. Thermo-gravimetric and differential thermal analysis (TG–DTA) results illuminated that Cu flowers sample has relatively higher activity to oxygen in air atmosphere compared to Cu octahedral cages. A well-defined, stable and fast amperometric response of glucose was observed when the Cu nanostructures were constructed as non-enzymatic glucose sensors. The Cu flowers modified electrode has higher sensitivity than Cu octahedral cages modified one.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 409:105–111. · 2.11 Impact Factor

Publication Stats

44 Citations
22.83 Total Impact Points

Institutions

  • 2013
    • Henan Institute of Science and Technology
      Honanfu, Henan Sheng, China
  • 2009–2011
    • Hunan University
      • College of Chemistry and Chemical Engineering
      Ch’ang-sha-shih, Hunan, China
  • 2008–2011
    • Jilin University
      • College of Chemistry
      Jilin, Jilin Sheng, China