Fe–Fe2O3–MnO2–sucrose–epoxy resin and O2 as reaction system and feed gas,separately,were used to prepare micro-nano hollow multiphase ceramic microspheres containing MnFe2O4absorbent by self-reactive quenching met...Fe–Fe2O3–MnO2–sucrose–epoxy resin and O2 as reaction system and feed gas,separately,were used to prepare micro-nano hollow multiphase ceramic microspheres containing MnFe2O4absorbent by self-reactive quenching method which is integrated with flame jet,selfpropagating high-temperature synthesis(SHS),and rapidly solidification.The morphologies and phase compositions of hollow microspheres were studied by scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),and energy dispersive spectroscopy.The results show that the quenching products are regular spherical substantially with hollow structure,particle size is between few hundreds nanometers and 5 lm.Phase compositions are diphase of Fe3O4,Mn3O4,and MnFe2O4,and the spinel soft magnetic ferrite MnFe2O4 with microwave magnetic properties is in majority.Collisions with each other,burst as well as‘‘refinement’’of agglomerate powders in flame field may be the main reasons for the formation of micro-nano hollow multiphase ceramic microspheres containing MnFeOabsorbent.展开更多
Herein, we report a "dissolution-reassembly" approach for preparation of N-doped hollow carbon spheres with mesoporous/microporous composite structure (H(Micro/Meso)CS). Basing on the compositional inhomogen...Herein, we report a "dissolution-reassembly" approach for preparation of N-doped hollow carbon spheres with mesoporous/microporous composite structure (H(Micro/Meso)CS). Basing on the compositional inhomogeneity inside the nanospheres of 3-aminophenol/formaldehyde (3-AF) polymerization, the internal 3-AF oligomer with low-molecular-weight is dissolved by acetone to form cavity. Then the dispersive 3-AF oligomer reassemble with silica oligomer as pore-forming agent and cetyltrimethyl-ammonium bromide as surfactant to form a mesoporous outer shell. In addition, the amount of acetone has a great influence on the morphology and structure of H(Micro/Meso)CS. The obtained H(Micro/Meso)CS shows uniform spherical and microporous/mesoporous shell structure and has a high specific capacity and excellent high rate capability.展开更多
By means of distillation precipitation polymerization,the silica-hybrid particles with polyazobenzene shell (PAzo@SiO2) microspheres were prepared with 6-(4-methoxy-4'-oxy-azobenzene) hexyl methacrylate (Azo-M) as...By means of distillation precipitation polymerization,the silica-hybrid particles with polyazobenzene shell (PAzo@SiO2) microspheres were prepared with 6-(4-methoxy-4'-oxy-azobenzene) hexyl methacrylate (Azo-M) as monomer,divinylbenzene (DVB) as cross-linker,and ～250 nm vinylated sol-gel silica particles as template. Hollow polyazobenzene microspheres were further developed after selective removal of the silica cores with HF solution. When the content of DVB related to Azo-M is 20 wt%,the acetonitrile is 200 mL,and the polymerization time is 4.5 h,the hollow PAzo microspheres with about 20 nm shell are successfully fabricated. These hollow PAzo microspheres have excellent reversible photoisomerization,and their first-order rate constant of trans-cis isomerization only decreases 11.8% compared with homopolymer of azobenzene (Homo-PAzo).展开更多
Hollow mesoporous silica spheres with magnetite cores(HMSMC) have been fabricated by Vacuum Nano-casting Route. The amount of magnetite cores and saturation magnetization value can be easily adjusted by changing the c...Hollow mesoporous silica spheres with magnetite cores(HMSMC) have been fabricated by Vacuum Nano-casting Route. The amount of magnetite cores and saturation magnetization value can be easily adjusted by changing the concentration of iron nitrate solution used in the synthesis procedure. Furthermore, the as-prepared HMSMCs still maintain narrow mesopore distribution, high surface area and large pore volume after the hollow cores of hollow mesoporous silica spheres were filled with magnetite particles. Specially, when the saturation magnetization value of as-prepared HMSMCs reaches 22.0 emu/g, the surface area and pore volume of corresponding HMSMCs are 149 m^2/g and 0.19 cm^3/g, respectively, and the pore size is 2.30 nm. The corresponding samples are characterized by X-ray diffraction, N_2 sorption isotherms, transmission electron microscopy and vibrating-sample magnetometer.展开更多
ZnO micro-nano spheres covered with ZnO nanowires were synthesized at 650 ℃ without using cataly-sts. Characterizations of the products by TEM, SEM, XRD, SAED and EDS showed that the ZnO nanowires were of high purity...ZnO micro-nano spheres covered with ZnO nanowires were synthesized at 650 ℃ without using cataly-sts. Characterizations of the products by TEM, SEM, XRD, SAED and EDS showed that the ZnO nanowires were of high purity and single-crystalline with hexagonal wurtzite structure. The diameter of ZnO nanowires ranges from 60 to 200 nm and the length is longer than 10 μm. The size of the ZnO micro-nano spheres ranges from hundreds of nanometers to tens of microns. At the same time, the growth mechanism of ZnO micro-nano spheres is discussed.展开更多
基金supported by the ational Natural Science Foundation of China (No. 51172282)
文摘Fe–Fe2O3–MnO2–sucrose–epoxy resin and O2 as reaction system and feed gas,separately,were used to prepare micro-nano hollow multiphase ceramic microspheres containing MnFe2O4absorbent by self-reactive quenching method which is integrated with flame jet,selfpropagating high-temperature synthesis(SHS),and rapidly solidification.The morphologies and phase compositions of hollow microspheres were studied by scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),and energy dispersive spectroscopy.The results show that the quenching products are regular spherical substantially with hollow structure,particle size is between few hundreds nanometers and 5 lm.Phase compositions are diphase of Fe3O4,Mn3O4,and MnFe2O4,and the spinel soft magnetic ferrite MnFe2O4 with microwave magnetic properties is in majority.Collisions with each other,burst as well as‘‘refinement’’of agglomerate powders in flame field may be the main reasons for the formation of micro-nano hollow multiphase ceramic microspheres containing MnFeOabsorbent.
基金the National Natural Science Foundation of China(No. 21676070)Hebei One Hundred-Excellent Innovative Talent Program(Ⅲ)(No. SLRC2017034)Beijing National Laboratory for Molecular Sciences
文摘Herein, we report a "dissolution-reassembly" approach for preparation of N-doped hollow carbon spheres with mesoporous/microporous composite structure (H(Micro/Meso)CS). Basing on the compositional inhomogeneity inside the nanospheres of 3-aminophenol/formaldehyde (3-AF) polymerization, the internal 3-AF oligomer with low-molecular-weight is dissolved by acetone to form cavity. Then the dispersive 3-AF oligomer reassemble with silica oligomer as pore-forming agent and cetyltrimethyl-ammonium bromide as surfactant to form a mesoporous outer shell. In addition, the amount of acetone has a great influence on the morphology and structure of H(Micro/Meso)CS. The obtained H(Micro/Meso)CS shows uniform spherical and microporous/mesoporous shell structure and has a high specific capacity and excellent high rate capability.
基金supported by the Outstanding Youth Fund of the National Natural Science Foundation of China (50825301)Open Fund of State Key Laboratory of Plastic Forming Simulation and Die & Mould Technology of HUST
文摘By means of distillation precipitation polymerization,the silica-hybrid particles with polyazobenzene shell (PAzo@SiO2) microspheres were prepared with 6-(4-methoxy-4'-oxy-azobenzene) hexyl methacrylate (Azo-M) as monomer,divinylbenzene (DVB) as cross-linker,and ～250 nm vinylated sol-gel silica particles as template. Hollow polyazobenzene microspheres were further developed after selective removal of the silica cores with HF solution. When the content of DVB related to Azo-M is 20 wt%,the acetonitrile is 200 mL,and the polymerization time is 4.5 h,the hollow PAzo microspheres with about 20 nm shell are successfully fabricated. These hollow PAzo microspheres have excellent reversible photoisomerization,and their first-order rate constant of trans-cis isomerization only decreases 11.8% compared with homopolymer of azobenzene (Homo-PAzo).
基金support of this research by the National Science Foundation of China(Grant No.50702072)Chinese Academy of Science(Grant No.KJCX2.YW.M02)+1 种基金National 863 Projects(Grant No.2007AA03Z317)Shanghai Nano-Science Program(Grant No.0852nm03900)
文摘Hollow mesoporous silica spheres with magnetite cores(HMSMC) have been fabricated by Vacuum Nano-casting Route. The amount of magnetite cores and saturation magnetization value can be easily adjusted by changing the concentration of iron nitrate solution used in the synthesis procedure. Furthermore, the as-prepared HMSMCs still maintain narrow mesopore distribution, high surface area and large pore volume after the hollow cores of hollow mesoporous silica spheres were filled with magnetite particles. Specially, when the saturation magnetization value of as-prepared HMSMCs reaches 22.0 emu/g, the surface area and pore volume of corresponding HMSMCs are 149 m^2/g and 0.19 cm^3/g, respectively, and the pore size is 2.30 nm. The corresponding samples are characterized by X-ray diffraction, N_2 sorption isotherms, transmission electron microscopy and vibrating-sample magnetometer.
文摘ZnO micro-nano spheres covered with ZnO nanowires were synthesized at 650 ℃ without using cataly-sts. Characterizations of the products by TEM, SEM, XRD, SAED and EDS showed that the ZnO nanowires were of high purity and single-crystalline with hexagonal wurtzite structure. The diameter of ZnO nanowires ranges from 60 to 200 nm and the length is longer than 10 μm. The size of the ZnO micro-nano spheres ranges from hundreds of nanometers to tens of microns. At the same time, the growth mechanism of ZnO micro-nano spheres is discussed.
