Selenium nanoparticles were prepared by a reverse microemulsion system. Sodium selenosulfate was used as selenium source. The results showed that hydrochloric acid concentration and reaction temperature had great infl...Selenium nanoparticles were prepared by a reverse microemulsion system. Sodium selenosulfate was used as selenium source. The results showed that hydrochloric acid concentration and reaction temperature had great influence on the morphology of products. The crystalline selenium nanowires and amorphous selenium nanorods were obtained in given condition.展开更多
Ni nanoparticles plating was prepared in reverse microemulsion. The deposition was carried out through the Brownian motion of water pools in the reverse microemulsion and the adsorption of water pools on the electrode...Ni nanoparticles plating was prepared in reverse microemulsion. The deposition was carried out through the Brownian motion of water pools in the reverse microemulsion and the adsorption of water pools on the electrode surface. Effects of electrolytic parameters on the size of Ni particles were studied. The performances of hydrogen evolution and hydrogen storage of the Ni nanoparticles plating electrode were also investigated. The results indicate that the size of Ni nanoparticles decreases with the increase of Ni2+ concentration and the decrease of current density. The electrochemical activity of Ni nanoparticles plating electrode is much higher than that of bulk Ni electrode.展开更多
Using the polymerizable hydrophobic styrene monomer as the dispersion medium and the traditional nonionic surfactant OP-10 as emulsifier, stable silver nanoparticles of narrow size distribution were prepared by a reve...Using the polymerizable hydrophobic styrene monomer as the dispersion medium and the traditional nonionic surfactant OP-10 as emulsifier, stable silver nanoparticles of narrow size distribution were prepared by a reverse （w/o） microemulsion method. The powder X-ray diffraction （XRD） pattern indicated that the obtained silver nanoparticles were of face-centered cubic structure. The results of the transmission electron microscopy （TEM） show that the final silver nanoparticles are of spherical structure with an average diameter of 15.2 nm and of a Gaussian distribution. The internal high-ordered structure of silver nanoparticles was characterized by the field-emission high-resolution transmission electron microscopy （FEHRTEM）, indicating that the silver is monocrystalline and it has only one nucleation site during the formation process of a nanoparticle. The time-resolved UV-visible absorption spectra was used to monitor the process of the reaction in situ. The results show that the concentration of silver nanoparticles increases but the size changes little and the morphology transforms from obvious ellipsoidal shape to nearly spherical shape during the process. The experimental results indicate that the droplets’ dynamic exchange which is closely related to the nature of surfactant film is the control factor of the kinetics. The dynamic exchange mechanism of silver nanoparticle formation is proposed to involve continual encounter of two separate droplets forming transient fused dimer in which the chemical reaction occurs followed by re-separation without combination. Attributed to the dual role of surfactant in the nanoparticle formation, tailored nanoparticles can be successfully synthesized in control in the premise of a certain stability of reverse microemulsion.展开更多
Al2O3 nanoparticles were prepared by polyethylene glycol octylphenyl ether(Triton X-100)/n-butyl alcohol/cyclohexane/ water W/O reverse microemulsion. The proper calcination temperature was determined at 1 150 ℃ by t...Al2O3 nanoparticles were prepared by polyethylene glycol octylphenyl ether(Triton X-100)/n-butyl alcohol/cyclohexane/ water W/O reverse microemulsion. The proper calcination temperature was determined at 1 150 ℃ by thermal analysis of the precursor products. The structures and morphologies of Al2O3 nanoparticles were characterized by X-ray diffraction, transmission electron microscopy and UV-Vis spectra. The influences of mole ratio of water to surfactant on the morphologies and the sizes of the Al2O3 nanoparticles were studied. With the increase of surfactant content, the particles size becomes larger. The agglomeration of nanoparticles was solved successfully. And the formation mechanisms of Al2O3 nanoparticles in the reverse microemulsion were also discussed.展开更多
Pd-Ag bimetallic alloy nanoparticles were synthesized by the reverse microemulsion method, and then deposited on A1203 to form the supported catalyst. The nanoparticles of Pd-Ag and Pd-Ag/AI203 samples were characteri...Pd-Ag bimetallic alloy nanoparticles were synthesized by the reverse microemulsion method, and then deposited on A1203 to form the supported catalyst. The nanoparticles of Pd-Ag and Pd-Ag/AI203 samples were characterized by UV/ Vis, HRTEM, EDX, XRD, and XPS. The test results indicated that Pd-Ag bimetallic alloy nanoparticles with a size of about 2 nm and a face-centered cubic （fcc） structure were formed in the measured area of microemulsion. The growth of nanopar- ticles was effectively limited within the droplet of micoremulsion. TEM image exhibited that the Pd-Ag alloy nanoparticles were well-dispersed on the A1203 support. The catalytic performance of various catalysts for selective hydrogenation of acetylene showed that a higher acetylene conversion and selectivity to ethylene upon acetylene hydrogenation was achieved on a nano-sized Pd-Ag bimetallic catalyst with a Pd/Ag alloy supported molar ratio of 1：1.5.展开更多
Nanosized particles of hydroxyapatite (HAP) were synthesized by reacting Ca(H_2PO_4)_2·H_2O solution complex with equimolar Ca(OH)_2 saturated solution in sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane w...Nanosized particles of hydroxyapatite (HAP) were synthesized by reacting Ca(H_2PO_4)_2·H_2O solution complex with equimolar Ca(OH)_2 saturated solution in sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane water-in-oil microemulsion.The formation of microemulsion strongly depended on water content w (w=[H_2O]/[AOT] molar ratio) and concentration of surfactant and cosurfactant (1-octanol).By the variety of conductivity with w and the partial ternary phase diagram derived from a series of demarcation points,we set the basic component of microemulsions:[AOT]=0.1M(mol/dm^3),[1-octanol]=0.1M and w=3-9.Dynamic light scattering (DLS),UV-visible absorbance,TEM analysis and X-ray diffraction were used to characterize the microemulsion,formation of particles and resulting HAP particles.At low water content(w<9),the water pool radius of the droplet in the Ca(H_2PO_4)_2·H_2O microemulsion lineally depended on w.The size of final HAP particles was strongly affected by water content w and reactant concentration.With increasing water content w from 3 to 9,the size of HAP particles increased from 10-20nm to 40-50 nm at reactant concentration [Ca(H_2PO_4)2·H_2O]=12×10^(-3) mol/dm^3.The resulting HAP particles were poorly crystallized and spherical in morphology.展开更多
In this study, the CaP/pDNA nanoparticles were prepared using Triton X-100/Butanol/Cyclohexane/Water reverse microemulsion system. Optimization of preparation conditions was based on evaluation of particle size by Box...In this study, the CaP/pDNA nanoparticles were prepared using Triton X-100/Butanol/Cyclohexane/Water reverse microemulsion system. Optimization of preparation conditions was based on evaluation of particle size by Box–Behnken design method. The particle sizes of the optimized CaP/pDNA nanoparticles were found to be 60.23 ± 4.72 nm, polydispersity index was 0.252 and pDNA encapsulate efficiency was more than 90%. The optimized CaP/pDNA nanoparticles have pH sensitivity and biocompatibility. Further, optimized CaP/pDNA nanoparticles showed higher transfection efficiency.展开更多
文摘Selenium nanoparticles were prepared by a reverse microemulsion system. Sodium selenosulfate was used as selenium source. The results showed that hydrochloric acid concentration and reaction temperature had great influence on the morphology of products. The crystalline selenium nanowires and amorphous selenium nanorods were obtained in given condition.
基金Projects(20673036,J0830415) supported by the National Natural Science Foundation of ChinaProject(09JJ3025) supported by Hunan Provincial Natural Science Foundation of ChinaProject(09GK3173) supported by the Planned Science and Technology Project of Hunan Province,China
文摘Ni nanoparticles plating was prepared in reverse microemulsion. The deposition was carried out through the Brownian motion of water pools in the reverse microemulsion and the adsorption of water pools on the electrode surface. Effects of electrolytic parameters on the size of Ni particles were studied. The performances of hydrogen evolution and hydrogen storage of the Ni nanoparticles plating electrode were also investigated. The results indicate that the size of Ni nanoparticles decreases with the increase of Ni2+ concentration and the decrease of current density. The electrochemical activity of Ni nanoparticles plating electrode is much higher than that of bulk Ni electrode.
文摘Using the polymerizable hydrophobic styrene monomer as the dispersion medium and the traditional nonionic surfactant OP-10 as emulsifier, stable silver nanoparticles of narrow size distribution were prepared by a reverse （w/o） microemulsion method. The powder X-ray diffraction （XRD） pattern indicated that the obtained silver nanoparticles were of face-centered cubic structure. The results of the transmission electron microscopy （TEM） show that the final silver nanoparticles are of spherical structure with an average diameter of 15.2 nm and of a Gaussian distribution. The internal high-ordered structure of silver nanoparticles was characterized by the field-emission high-resolution transmission electron microscopy （FEHRTEM）, indicating that the silver is monocrystalline and it has only one nucleation site during the formation process of a nanoparticle. The time-resolved UV-visible absorption spectra was used to monitor the process of the reaction in situ. The results show that the concentration of silver nanoparticles increases but the size changes little and the morphology transforms from obvious ellipsoidal shape to nearly spherical shape during the process. The experimental results indicate that the droplets’ dynamic exchange which is closely related to the nature of surfactant film is the control factor of the kinetics. The dynamic exchange mechanism of silver nanoparticle formation is proposed to involve continual encounter of two separate droplets forming transient fused dimer in which the chemical reaction occurs followed by re-separation without combination. Attributed to the dual role of surfactant in the nanoparticle formation, tailored nanoparticles can be successfully synthesized in control in the premise of a certain stability of reverse microemulsion.
基金Project(2002AA323100) supported by the National High-Tech Research and Development Program of China
文摘Al2O3 nanoparticles were prepared by polyethylene glycol octylphenyl ether(Triton X-100)/n-butyl alcohol/cyclohexane/ water W/O reverse microemulsion. The proper calcination temperature was determined at 1 150 ℃ by thermal analysis of the precursor products. The structures and morphologies of Al2O3 nanoparticles were characterized by X-ray diffraction, transmission electron microscopy and UV-Vis spectra. The influences of mole ratio of water to surfactant on the morphologies and the sizes of the Al2O3 nanoparticles were studied. With the increase of surfactant content, the particles size becomes larger. The agglomeration of nanoparticles was solved successfully. And the formation mechanisms of Al2O3 nanoparticles in the reverse microemulsion were also discussed.
文摘Pd-Ag bimetallic alloy nanoparticles were synthesized by the reverse microemulsion method, and then deposited on A1203 to form the supported catalyst. The nanoparticles of Pd-Ag and Pd-Ag/AI203 samples were characterized by UV/ Vis, HRTEM, EDX, XRD, and XPS. The test results indicated that Pd-Ag bimetallic alloy nanoparticles with a size of about 2 nm and a face-centered cubic （fcc） structure were formed in the measured area of microemulsion. The growth of nanopar- ticles was effectively limited within the droplet of micoremulsion. TEM image exhibited that the Pd-Ag alloy nanoparticles were well-dispersed on the A1203 support. The catalytic performance of various catalysts for selective hydrogenation of acetylene showed that a higher acetylene conversion and selectivity to ethylene upon acetylene hydrogenation was achieved on a nano-sized Pd-Ag bimetallic catalyst with a Pd/Ag alloy supported molar ratio of 1：1.5.
文摘Nanosized particles of hydroxyapatite (HAP) were synthesized by reacting Ca(H_2PO_4)_2·H_2O solution complex with equimolar Ca(OH)_2 saturated solution in sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane water-in-oil microemulsion.The formation of microemulsion strongly depended on water content w (w=[H_2O]/[AOT] molar ratio) and concentration of surfactant and cosurfactant (1-octanol).By the variety of conductivity with w and the partial ternary phase diagram derived from a series of demarcation points,we set the basic component of microemulsions:[AOT]=0.1M(mol/dm^3),[1-octanol]=0.1M and w=3-9.Dynamic light scattering (DLS),UV-visible absorbance,TEM analysis and X-ray diffraction were used to characterize the microemulsion,formation of particles and resulting HAP particles.At low water content(w<9),the water pool radius of the droplet in the Ca(H_2PO_4)_2·H_2O microemulsion lineally depended on w.The size of final HAP particles was strongly affected by water content w and reactant concentration.With increasing water content w from 3 to 9,the size of HAP particles increased from 10-20nm to 40-50 nm at reactant concentration [Ca(H_2PO_4)2·H_2O]=12×10^(-3) mol/dm^3.The resulting HAP particles were poorly crystallized and spherical in morphology.
基金the Natural Science Foundation Committee of China for the financial support (No.81173004 and No.81202483)
文摘In this study, the CaP/pDNA nanoparticles were prepared using Triton X-100/Butanol/Cyclohexane/Water reverse microemulsion system. Optimization of preparation conditions was based on evaluation of particle size by Box–Behnken design method. The particle sizes of the optimized CaP/pDNA nanoparticles were found to be 60.23 ± 4.72 nm, polydispersity index was 0.252 and pDNA encapsulate efficiency was more than 90%. The optimized CaP/pDNA nanoparticles have pH sensitivity and biocompatibility. Further, optimized CaP/pDNA nanoparticles showed higher transfection efficiency.
