Preparation of Y_2O_3 Nanoparticles Organosol by Microemulsion Method

Y 2O 3 nanoparticles organosol coated with DBS was prepared by microemulsion method. The optimum preparative conditions of Y 2O 3 nanoparticles organosol were obtained. TEM analysis indicates that the prepared Y 2O 3 nanoparticles are spherical in shape. The size is about 5 nm. The size distribution is in the narrow range and no agglomerates are observed. Y 2O 3 nanoparticles coated with DBS are easy to dissolve in weak polar solvents.

Synthesis of Long Afterglow Phosphors MAl_2O_4∶Eu^(2+), Dy~ (3+)(M=Ca, Sr, Ba) by Microemulsion Method and Their Luminescent Properties

Long afterglow phosphors MAl2O4：Eu^2＋ , Dy^3＋ （M = Ca, Sr, Ba） were synthesized by microemulsion method, and their crystal structure and luminescent properties were compared and investigated. XRD patterns of samples indicate that phosphors CaAl2O4：Eu^2＋, Dy^3＋ and SrAl2O4 ： Eu^2＋, Dy^3＋ are with monoelinie crystal structure and phosphor BaAl2O4：Eu^2＋ , Dy^3＋ is with hexagonal crystal structure. The wide range of excitation spectrum of phosphors MAl2O4： Eu^2 ＋ , Dy^3＋ （M = Ca,Sr, Ba） indicates that the luminescent materials can he excited by light from ultraviolet ray to visible light and the maximum emission wavelength of phosphors MAl2O4：Eu^2＋ , Dy^3＋ （M = Ca, Sr, Ba） is found mainly at λem of 440 nm （M = Ca）, 520 nm （M = Sr） and 496 nm （M = Ba） respectively, the corresponding colors of emission light are blue, green and eyna-green respectively. The afterglow decay tendency of phosphors can he summarized as three processes： initial rapid decay, intermediate transitional decay and very long slow decay. Afterglow decay curves coincide with formula I = At^ - n, and the sequence of afterglow intensity and time is Sr 〉 Ca 〉 Ba.

A microemulsion method for preparation of thiol-functionalized gold nanoparticles

A new microemulsion method using tetraoctylammonium bromide as a cationic surfactant has been formulated to fabricate thiol-functionalized gold nanoparticles, The nanoparticles were compared with those synthesized by the multistep Brust two-phase method.The nanoparticle sizes and size distributions fabricated by the two methods were characterized by UV-vis ahsorbance spectroscopy and transmittance electron microscopy. The simple microemulsion method produced the same results as those obtained by the Brust method,

Effect of Preparation Method on Surface Area and Crystalline Form of CeO_2-ZrO_2 Solid Solution

The CeO_2-ZrO_2 solid solutions were prepared by a reverse microemulsion method. The effect of preparation parameters on the surface area and crystalline form of the solid solutions were studied by the BET surface area and XRD analysis. The studies indicate that the separation of the microemulsion phase during the preparation procedure can decrease the specific surface area of sample, adding hydrogen peroxide in the matrix solution can increase the specific surface area and stability of sample. The surface area of sample calcined at 550 ℃ for 5 h is 149 m^2·g^(-1), and that calcined at 900 ℃ for 6 h is 88 m^2·g^(-1). The sample with tetragonal symmetry Ce_(0.5)Zr_(0.5)O_2 phase has a higher stability.

Synthesis and electrochemical properties of SnO_2-polyaniline composite

The SnO2-polyaniline(SnO2-PAn) composite was prepared by microemulsion polymerization method using aniline,ammonium peroxodisulfate and SnO2 as starting materials.The SnO2-PAn composite was characterized by X-ray diffractometer,scanning electron microscope and electrochemical techniques.The results show that PAn in the composites is amorphous.PAn formed in the reaction is deposited preferentially on the SnO2 particles,giving a SnO2-PAn composite,in which SnO2 is coated with PAn.SnO2-PAn composite shows a reversible capacity of 657.6 mA·h/g and the capacity loss per cycle is only 0.092% after 80 cycles,suggesting that SnO2-PAn composite is a promising anode material for lithium ion batteries.

Kinetics of ring-opening polymerization of octamethylcyclotetrasiloxane in microemulsion

Polysiloxane latexes were prepared by microemulsion polymerization of octamethylcyclotetrasiloxane （D4） in the absence of co-emulsifier with octadecyl trimethyl ammonium chloride as a cationic emulsifier and potassium hydrate as an initiator. The particle size was determined by the dynamic light scattering （DLS） technique and the reaction rates of the polymerization were discussed. Furthermore, the kinetics was studied by an initial-rate method, and the effects of the monomer, emulsifier and initiator concentrations and the temperature on polymerization conversions were investigated. From the kinetic results, the rate of polymerization, Rp at 80℃ can be expressed as Rp = k[D4]^0.79 [OTAC]^0.64[KOH]^0.38 and the aonarent activation energy（Ea）. which was determined by half-period method, is 95.32 kJ mol^-1.

Bi/3DPG composite structure optimization realizes high specific capacity and rapid sodium-ion storage

As an anode material for sodium-ion batteries(SIBs),bismuth(Bi)has attracted widespread attention due to its suitable voltage platform and high volumetric energy density.However,the severe volume expansion of Bi during charging and discharging leads to a rapid decline in battery capacity.Loading Bi on the graphene can relieve volume expansion and improve electrochemical performance.However,excessive loading of Bi on graphene will cause the porosity of the composite material to decrease,which leads to a decrease of the Na+transmission rate.Herein,the Bi/three-dimensional porous graphene(Bi/3DPG)composite material was prepared and the pore structure was optimized to obtain the medium-load Bi/3DPG(Bi/3DPG-M)with better electrochemical performance.Bi/3DPG-M exhibited a fast kinetic process while maintaining a high specific capacity.The specific capacity still remained at 270 mA·h·g^(−1)(93.3%)after 500 cycles at a current density of 0.1 A·g^(−1).Even at 5 A·g^(−1),the specific capacity of Bi/3DPG-M could still reach 266.1 mA·h·g^(−1).This work can provide a reference for research on the use of alloy–graphene composite in the anode of SIBs.

Luminescence properties of Eu^(3+):NaGd(WO_4_)2 nanoparticles and nanorods

The NaGd(WO4)2:Eu3+ phosphors were prepared by the microemulsion mediated hydrothermal method. The morphology and size of the samples could be dependent on the pH in the initial solution. These phosphors obtained had a strong absorption at 395 nm matching with the popular emission of near-UV LED chips, and could emit intense red light at 616 nm. The small ellipsoid-like particles or short rods were provided with large parameters of oscillator strength?2 and asymmetry ratio. Compared to the ellip-soid-like phosphors, the rod-like phosphors took on stronger emission, longer lifetime and larger quantum efficiency. This work demonstrated that the one-dimension NaGd(WO4)2:Eu3+ phosphors might be a more favorable device than zero-dimension ones for photoluminescence.