Planar micro-supercapacitors show great potential as the energy storage unit in miniaturized electronic devices. Asymmetric structures have been widely inves- tigated in micro-supercapacitors, and carbon-based materia...Planar micro-supercapacitors show great potential as the energy storage unit in miniaturized electronic devices. Asymmetric structures have been widely inves- tigated in micro-supercapacitors, and carbon-based materials are commonly applied in the electrodes. To integrate different metal oxides in both electrodes in micro-supercapacitors, the critical challenge is the pairing of different faradic metal oxides. Herein, we propose a strategy of matching the voltage and capadtance of two faradic materials that are fully integrated into one high-performance asymmetric micro-supercapacitor by a facile and controllable fabrication process. The fabricated micro-supercapacitors employ MnO2 as the positive active material and Fe203 as the negative active material, respectively. The planar asymmetric micro-supercapacitors possess a high capacitance of 60 F-cm-3, a high energy density of 12 mW.h.cm-3, and a broad operation voltage range up to 1.2 V.展开更多
The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy...The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy and transmission electron microscopy. It is found that the freshly prepared hydrosol of Fe2O3 nanoparticles is not stable. The surface pressure increases with the aging time and finally approaches a constant, and the smaller the concentration is, the smaller the surface pressure is stabilized at and the shorter the time the hydrosol reaching stable needs. The surface pressure also increases with compression until collapsed, and the longer the hydrosol is aged, the higher the collapsing pressure is. A uniform and compact film composed of nanoparticles with an average diameter of about 2-3 nm on the air-hydrosol interface is observed by Brewster angle microscope and transmission electron microscope.展开更多
Fe_2O_3 sol with the particle diameter of 3-5 nm was flocculated by the addition of SDS, and the flocculate formed was redispersed by the further addition of that surfactant. Thus the surfactant bilayer was formed on ...Fe_2O_3 sol with the particle diameter of 3-5 nm was flocculated by the addition of SDS, and the flocculate formed was redispersed by the further addition of that surfactant. Thus the surfactant bilayer was formed on the surface of Fe_2O_3. The emulsion polymerization of styrene(St) adsolubilized on the surfactant adsorbed bilayer was carried out by initiator potassium persulfate(KPS). The UV-Vis and surface photovoltage spectra(SPS) indicate that the Fe_2O_3 particles were encapsulated in polystyrene(PSt) successfully.展开更多
Using a liquid-solid phase inversion method, a hybrid matrix poly(vinylidene fluoride)(PVDF) membrane was prepared with alumina(Al2O3) nanoparticle addition. Pd/Fe nanoparticles(NPs) were successfully immobili...Using a liquid-solid phase inversion method, a hybrid matrix poly(vinylidene fluoride)(PVDF) membrane was prepared with alumina(Al2O3) nanoparticle addition. Pd/Fe nanoparticles(NPs) were successfully immobilized on the Al2O3/PVDF membrane, which was characterized by Scanning Electron Microscopy(SEM) and Transmission Electron Microscopy(TEM). The micrographs showed that the Pd/Fe NPs were dispersed homogeneously. Several important experimental parameters were optimized, including the mechanical properties, contact angle and surface area of Al2O3/PVDF composite membranes with different Al2O3 contents. At the same time, the ferrous ion concentration and the effect of hydrophilization were studied. The results showed that the modified Al2O3/PVDF membrane functioned well as a support. The Al2O3/PVDF membrane with immobilized Pd/Fe NPs exhibited high efficiency in terms of dichloroacetic acid(DCAA) dechlorination. Additionally, a reaction pathway for DCAA dechlorination by Pd/Fe NPs immobilized on the Al2O3/PVDF membrane system was proposed.展开更多
A biosensor based on hemoglobin-Fe304@SiO2 nanoparticle bioconjunctions modified indium-tin-oxide (Hb/Fe3O4@SiOz/ITO) electrode was fabricated to determine the concentration of H202. UV-vis absorption spectra, fouri...A biosensor based on hemoglobin-Fe304@SiO2 nanoparticle bioconjunctions modified indium-tin-oxide (Hb/Fe3O4@SiOz/ITO) electrode was fabricated to determine the concentration of H202. UV-vis absorption spectra, fourier transform infrared (FT-IR) spectroscopy, cyclic voltammetry (CV) and high-resolution transmission electron microscopy (HRTEM) were used to characterize the bioconjunction of Fe3O4@SiO2 with Hb. Experimental results demonstrate that the immobilized Hb on the Fe3O4@SiO2 matrix retained its native structure well. In addition, Fe3O4@SiO2 nanoparticles (NPs) are very effective in facilitating electron transfer of the immobilized enzyme, which can be attributed to the unique nanostructure and larger surface area of the Fe304@SiO2 NPs. The biosensor displayed good performance for the detection of H2O2 with a wide linear range from 2.03×10^-6 to 4.05×10^3 mol/L and a detection limit of 0.32 μmol/L. The resulting biosensor exhibited fast amperometric response, good stability, reproducibility, and selectivity to H2O2.展开更多
In this paper, the laccase immobilized on Fe304@SiO2-NH2 nanoparticles was successfully prepared by the glutaraldehyde cross-linking method. The degradations of 2,4-diehlorophenol (2,4-DCP) catalyzed by laccase and ...In this paper, the laccase immobilized on Fe304@SiO2-NH2 nanoparticles was successfully prepared by the glutaraldehyde cross-linking method. The degradations of 2,4-diehlorophenol (2,4-DCP) catalyzed by laccase and immobilized laccase were carried out. The optimal conditions regarding degradation efficiency were also discussed, which include reaction time, pH value, temperature, concentration of 2,4-DCP and laccase. When laccase was immobilized on Fe304@SiO2-NH2 carrier by crosslinking with glutaraldehyde, the stability and repetition were im- proved significantly. The removal efficiency of 2,4-DCP by immobilized laccase still remained over 59% after six cycles of operation. Degradation of 2,4-DCP is a first-order reaction and the activation energies of 2,4-DCP catalyzed by laccase and immobilized laccase are 51.93 kJ·mol-1 strate the immobilized laccase had a faster degradation Fe304@MSS-NH2 can promote the degradation reaction. and 44.12 kJ·mol-1, respectively. The results demonrate than the free laccase; the magnetic carrier展开更多
基金This work was supported by the National Key Research and Development Program of China (No. 2016YFA0202603), the National Basic Research Program of China (No. 2013CB934103), the Programme of Introducing Talents of Discipline to Universities (No. B17034), the National Natural Science Foundation of China (Nos. 51521001, 51502227, 51579198, and 51302203), the National Natural Science Fund for Distinguished Young Scholars (No. 51425204), and the Fundamental Research Funds for the Central Universities (WUT: 2016III001, 2016III005, 2016III006).
文摘Planar micro-supercapacitors show great potential as the energy storage unit in miniaturized electronic devices. Asymmetric structures have been widely inves- tigated in micro-supercapacitors, and carbon-based materials are commonly applied in the electrodes. To integrate different metal oxides in both electrodes in micro-supercapacitors, the critical challenge is the pairing of different faradic metal oxides. Herein, we propose a strategy of matching the voltage and capadtance of two faradic materials that are fully integrated into one high-performance asymmetric micro-supercapacitor by a facile and controllable fabrication process. The fabricated micro-supercapacitors employ MnO2 as the positive active material and Fe203 as the negative active material, respectively. The planar asymmetric micro-supercapacitors possess a high capacitance of 60 F-cm-3, a high energy density of 12 mW.h.cm-3, and a broad operation voltage range up to 1.2 V.
基金Funded by the National Natural Science Foundation of China (50672089)the Encouraging Foundation for the Scientific Research of the Excellent Young and Middleaged Scientists in Shandong Province(2006BS04034)
文摘The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy and transmission electron microscopy. It is found that the freshly prepared hydrosol of Fe2O3 nanoparticles is not stable. The surface pressure increases with the aging time and finally approaches a constant, and the smaller the concentration is, the smaller the surface pressure is stabilized at and the shorter the time the hydrosol reaching stable needs. The surface pressure also increases with compression until collapsed, and the longer the hydrosol is aged, the higher the collapsing pressure is. A uniform and compact film composed of nanoparticles with an average diameter of about 2-3 nm on the air-hydrosol interface is observed by Brewster angle microscope and transmission electron microscope.
基金Supported by the National Natural Science Foundation of China(No. 2 99730 2 6 and 2 0 0 75 0 2 8) ,K.C.Wang Post-Doctoral Research Award Fund of Chinese Academ y of Sciences,and China Postdoctoral Science Foundation
文摘Fe_2O_3 sol with the particle diameter of 3-5 nm was flocculated by the addition of SDS, and the flocculate formed was redispersed by the further addition of that surfactant. Thus the surfactant bilayer was formed on the surface of Fe_2O_3. The emulsion polymerization of styrene(St) adsolubilized on the surfactant adsorbed bilayer was carried out by initiator potassium persulfate(KPS). The UV-Vis and surface photovoltage spectra(SPS) indicate that the Fe_2O_3 particles were encapsulated in polystyrene(PSt) successfully.
基金supported by the Nature Science Foundation of Heilongjiang Province (No. B201410)the Postdoctoral Foundation Project of Heilongjiang Province (No. LBH-Z13128)+3 种基金the Science and Technology Research Program of Education Bureau of Heilongjiang Province (No. 12531206)the Special Scientific Research Projects of Harbin Normal University (12XQXG02)the National Nature Science Foundation of China (No. 41030743)the National Nature Science Foundation of China (No. 42171217)
文摘Using a liquid-solid phase inversion method, a hybrid matrix poly(vinylidene fluoride)(PVDF) membrane was prepared with alumina(Al2O3) nanoparticle addition. Pd/Fe nanoparticles(NPs) were successfully immobilized on the Al2O3/PVDF membrane, which was characterized by Scanning Electron Microscopy(SEM) and Transmission Electron Microscopy(TEM). The micrographs showed that the Pd/Fe NPs were dispersed homogeneously. Several important experimental parameters were optimized, including the mechanical properties, contact angle and surface area of Al2O3/PVDF composite membranes with different Al2O3 contents. At the same time, the ferrous ion concentration and the effect of hydrophilization were studied. The results showed that the modified Al2O3/PVDF membrane functioned well as a support. The Al2O3/PVDF membrane with immobilized Pd/Fe NPs exhibited high efficiency in terms of dichloroacetic acid(DCAA) dechlorination. Additionally, a reaction pathway for DCAA dechlorination by Pd/Fe NPs immobilized on the Al2O3/PVDF membrane system was proposed.
基金Project supported by the National Natural Science Foundation of China (Nos. 20905010, 20905016), Jiangsu Provincial Natural Science Foundation (No. BK2008147), Guangxi Natural Science Foundation (No. 0991082), and China Postdoctoral Science Foundation (No. 20100471293).
文摘A biosensor based on hemoglobin-Fe304@SiO2 nanoparticle bioconjunctions modified indium-tin-oxide (Hb/Fe3O4@SiOz/ITO) electrode was fabricated to determine the concentration of H202. UV-vis absorption spectra, fourier transform infrared (FT-IR) spectroscopy, cyclic voltammetry (CV) and high-resolution transmission electron microscopy (HRTEM) were used to characterize the bioconjunction of Fe3O4@SiO2 with Hb. Experimental results demonstrate that the immobilized Hb on the Fe3O4@SiO2 matrix retained its native structure well. In addition, Fe3O4@SiO2 nanoparticles (NPs) are very effective in facilitating electron transfer of the immobilized enzyme, which can be attributed to the unique nanostructure and larger surface area of the Fe304@SiO2 NPs. The biosensor displayed good performance for the detection of H2O2 with a wide linear range from 2.03×10^-6 to 4.05×10^3 mol/L and a detection limit of 0.32 μmol/L. The resulting biosensor exhibited fast amperometric response, good stability, reproducibility, and selectivity to H2O2.
基金support from the National Natural Science Foundation of China (Grant No. 20971043 and No. 20577010), the Open Project Program of State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University.
文摘In this paper, the laccase immobilized on Fe304@SiO2-NH2 nanoparticles was successfully prepared by the glutaraldehyde cross-linking method. The degradations of 2,4-diehlorophenol (2,4-DCP) catalyzed by laccase and immobilized laccase were carried out. The optimal conditions regarding degradation efficiency were also discussed, which include reaction time, pH value, temperature, concentration of 2,4-DCP and laccase. When laccase was immobilized on Fe304@SiO2-NH2 carrier by crosslinking with glutaraldehyde, the stability and repetition were im- proved significantly. The removal efficiency of 2,4-DCP by immobilized laccase still remained over 59% after six cycles of operation. Degradation of 2,4-DCP is a first-order reaction and the activation energies of 2,4-DCP catalyzed by laccase and immobilized laccase are 51.93 kJ·mol-1 strate the immobilized laccase had a faster degradation Fe304@MSS-NH2 can promote the degradation reaction. and 44.12 kJ·mol-1, respectively. The results demonrate than the free laccase; the magnetic carrier