Ag2S/Ag2WO4 composite microrods,with lengths of 0.2-1μm and diameters of 20-30 nm,were fabricated by a facile sonochemical route.The as-synthesized products were intensively investigated by a series of physicochemica...Ag2S/Ag2WO4 composite microrods,with lengths of 0.2-1μm and diameters of 20-30 nm,were fabricated by a facile sonochemical route.The as-synthesized products were intensively investigated by a series of physicochemical characterizations,such as N2 physical adsorption,X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Fourier transform infrared spectroscopy,diffuser reflectance spectroscopy,X-ray photoelectron spectroscopy,photoluminescence spectroscopy and photocurrent response measurements.Ultrasonic irradiation yields an obvious improvement in the photocatalyst texture,for example,an increase in crystallinity and surface area.Moreover,sonochemically fabricated Ag2S/Ag2WO4 microrods display strong visible light absorption and a high transient photocurrent response.The produced intimate Ag2S/Ag2WO4interface between Ag2S and Ag2WO4 crystal phases largely promotes the separation of photogenerated holes and electrons.High photocatalytic activity and stability were obtained over Ag2S/Ag2WO4composite microrods.The dye degradation rate constant of Ag2S/Ag2WO4 was 4.7 times and 29.8times higher than that of bare Ag2WO4 and Ag2S,respectively.展开更多
To explore the application of the characteristics of metallic microparticles, alternating current electric trapping of the SU-8 microrods coated with a thin gold layer by the chemical approach is investigated. Positiv...To explore the application of the characteristics of metallic microparticles, alternating current electric trapping of the SU-8 microrods coated with a thin gold layer by the chemical approach is investigated. Positive dielectrophoresis is used to absorb the gold-coated SU-8 microrods at the edge of the parallel electrodes, thereby forming chains to connect the electrodes. This is a fast automatic microcircuit formation process. Moreover, a non-charged molecule is modified on the surface of the gold-coated SU-8 microrod, and the modified microrods are controlled by the alternating electric field to form a number of chains. The different chains between the parallel electrodes consist of various parallel circuits. In order to compare these chains with different electric surfaces, the impedances of the metallic and modified microrods are measured and compared, and the results show that the gold-coated microrods act as pure resistors, while the microrods functionalized by a non-charged molecule behave as good capacitors.展开更多
Microfluidics is a promising system for the manipulation of micro-nano particles and fluids. In this platform, alternating current （AC） electric field is usual an effective tool for the general particles control. Ho...Microfluidics is a promising system for the manipulation of micro-nano particles and fluids. In this platform, alternating current （AC） electric field is usual an effective tool for the general particles control. However, traditional work paid more attention on the regular spherical particles with no obvious distinction when rotating, resulting in imprecise rotation speed calculation. In essence, non-spherical especially biocompatible particles are not only important for biology application but also significant for obtaining accurate rotating results. Hence, in this paper, SU-8, one of the most biocompatible materials was selected as the manipulation object. AC electric field is employed to rotate SU-8 microrods, in order to obtain a controllable rotation angle for both the accurate experimental results and biosensor applications. Firstly, Clausius-Mossotti（CM） factors frequency spectra with different surface conductance and medium conductivities are presented, thereby the theoretical formula is carried out, including both the torque and rotation velocity expressions of SU-8 microrods. Moreover, simulations for the electric field distribution are developed, indicating the rotating direction. Secondly, the quadrupole electrodes are used to generate rotating electric field, and the electrorotation of SU-8 microrods in different medium is carried out, showing that the particles rotate in the opposite direction of the electric field, meanwhile, the peak frequency increases with the conductivity increases. Finally, the experimental results are discussed and compared with theoretical analysis, and the comparison result shows that they have a good agreement. This work proposes an effective and controllable method to rotate microrods, showing extend application potentials in microelectronics and biosensors.展开更多
ZnO microrods are synthesized using the vapor phase transport method, and the magnetron sputtering is used to decorate the A1 nanoparticles （NPs） on a single ZnO microrod. The micro-PL and I-V responses are measured...ZnO microrods are synthesized using the vapor phase transport method, and the magnetron sputtering is used to decorate the A1 nanoparticles （NPs） on a single ZnO microrod. The micro-PL and I-V responses are measured before and after the decoration orAl NPs. The FDTD stimulation is also carried out to demonstrate the optical field distribution around the decoration of Al NPs on the surface of a ZnO microrod. Due to an implementation of AI NPs, the ZnO microrod exhibits an improved photoresponse behavior. In addition, AI NPs induced localized surface plasmons （LSPs） as well as improved optical field confinement can be ascribed to an enhancement of ultraviolet （UV） response. This research provides a method for improving the responsivity of photodetectors.展开更多
Tetrapod-shaped ZnO whiskers and microrods were synthesized in one crucible by thermal evaporation of Zn/C mixtures at 930 ℃ in air without any catalyst.The digital camera,optical microscopy,scanning electron microsc...Tetrapod-shaped ZnO whiskers and microrods were synthesized in one crucible by thermal evaporation of Zn/C mixtures at 930 ℃ in air without any catalyst.The digital camera,optical microscopy,scanning electron microscopy,energy dispersive X-ray spectroscopy,and X-ray diffraction techniques were used to study the morphologies and crystal structures of these tetrapod-shaped ZnO microcrystals.The results show that these two types of ZnO tetrapods are grown at different heights within the same crucible.The legs of these tetrapod-shaped ZnO crystals are hexagonally faceted.Some tetrapod-shaped ZnO whiskers show hierarchical structures.A short button-like hexagonal ZnO microcrystal is observed at the triple junctions of some tetrapod-shaped ZnO whiskers.The tetrapod-shaped ZnO microrods are capped by two sets of hexagonal pyramids with two different groups of crystal planes for the surfaces.These two types of tetrapod-shaped ZnO microcrystals have different side faces and aspect ratio,which are believed to be the result of their different growth behaviors.The octa-twin model was used to discuss the different growth behaviors of these two types of ZnO tetrapods.The crystal planes of the legs and the pyramids were determined.展开更多
New lanthanide metal-organic framework（MOF） nano/microrods, [C4mim]Cl-Eu-MOF, [C8mim]Cl-Eu- MOF and [C12mim]Cl-Eu-MOF, were conveniently synthesized via an ionic liquid-assisted hydrothermal method and characterized...New lanthanide metal-organic framework（MOF） nano/microrods, [C4mim]Cl-Eu-MOF, [C8mim]Cl-Eu- MOF and [C12mim]Cl-Eu-MOF, were conveniently synthesized via an ionic liquid-assisted hydrothermal method and characterized by means of powder X-ray diffraction（XRD）, Fourier transform infrared spectroscopy（FTIR）, thermo- gravimetric analysis（TG） and transmission electron microscopy（TEM）. The obtained nano/microrods with low sur- face areas were efficient for the removal of Congo red（CR） from aqueous solutions. Under the optimum conditions, [C4mim]Cl-Eu-MOF with a specific surface area of 5.1 m^2/g exhibited an ultrahigh adsorption capacity of 2606 mg/g toward CR. Notably, the adsorption efficiency of [C4mim]Cl-Eu-MOF for CR via nano/microscale stacking can be directly demonstrated by TEM. In-depth understanding of CR removal by [C4mim]Cl-Eu-MOF nano/microrods was also supported by FTIR, Raman spectroscopy and zeta potential analyses.展开更多
The morphology of MAX phase powders significantly influences their microwave absorption properties.However,the traditional synthesis via solid-state reactions produces irregular powders,and the preparation of MAX phas...The morphology of MAX phase powders significantly influences their microwave absorption properties.However,the traditional synthesis via solid-state reactions produces irregular powders,and the preparation of MAX phase powders with specific morphology remains a challenge.Herein,(VTiCr)Al C MAX phase microrods were fabricated for the first time in NaCl/KCl molten salts using vanadium,titanium,chromium,aluminum,and short carbon fibers as precursors.It was found that despite acting as a carbon source,carbon fibers also acted as sacrificial templates.By adjusting the molar ratio of metal powders and short carbon fibers,a series of carbon fiber@(V_(0.8)Ti_(0.1)Cr_(0.1))_(2)AlC microrods with core-sheath structure were also obtained.Carbon fiber@(V_(0.8)Ti_(0.1)Cr_(0.1))_(2)AlC microrods with a molar ratio of 8:2 showed the optimum microwave absorption performance.The reflection loss(RL)value reached up to–63.26 d B at 2.40 mm,and the effective absorption bandwidth(EAB)was about 5.28 GHz with a thickness of2.02 mm.Based on the electromagnetic parameter analysis and theoretical simulation,the enhanced microwave absorption performance was attributed to the synergistic effect of different factors like dielectric loss,magnetic loss,multiple reflection,and scattering.This work offers a facile route to modulate the morphology of MAX phase powders and may accelerate its application as microwave absorbers.展开更多
Developing metal-organic framework(MOF)-based materials with good cyclic stability is the key to their practical application. Fluorinated organic compounds are usually highly chemically stability due to the high elect...Developing metal-organic framework(MOF)-based materials with good cyclic stability is the key to their practical application. Fluorinated organic compounds are usually highly chemically stability due to the high electronegativity of fluorine. Also, the pillared-layer structures based on coordination bonds have better structure and thermal stability than those based on hydrogen bonds. Herein, the fluorinated pillared-layer [Ni(2,3,4,5-tetrafluorobenzoic acid)(4,4-bipyridine)]nMOF([Ni(TFBA)(Bpy)]n) materials were constructed through a facile room-temperature solution reaction and used as electrode materials for supercapacitors. Surprisingly, the size/morphology of Ni(TFBA)(Bpy)nMOFs could be adjusted by varying the synthesis time. Benefting from the short ion diffusion length, unique pillar-layer structure, and strong intercomponent synergy of organic ligands, the Ni(TFBA)(Bpy)nMOF microrods showed a higher electrochemical energy storage capability than bulk MOFs. At the same time, compared to the non-fluorinated [Ni(benzoic acid)(Bpy)]nMOFs(31.5% capacitance decay), the fluorinated Ni(TFBA)(Bpy)n MOFs have a higher cycle stability with only 2.6% capacitance loss after 5000 cycles at 3 m A/cm^(2).展开更多
Cyclic voltammetry and chronopotentiometry have been used to study the Sb-doped Ti/SnO2 anodes prepared by magnetron sputtering. The results showed that magnetron sputtering condition influenced the surface morphology...Cyclic voltammetry and chronopotentiometry have been used to study the Sb-doped Ti/SnO2 anodes prepared by magnetron sputtering. The results showed that magnetron sputtering condition influenced the surface morphology and the properties of the anodes. After the Ti substrate was tempered in Ar at 600 ℃ for 1 h, Till1.5 on the surface generated from the acid etching was replaced by needle-like TiO2. The SnO2 coating on the above Ti substrate by magnetron sputtering with post-annealing was comprised of microrod and different with the traditional Ti/ SnO2 anode. The accelerated service life test showed that the microrod SnO2 anode gained the longest service time. The anode exhibited oscillations in the chronopotentiometry curves, and the microrod SnO2 coating almost dissolved after the life test. A model of layer-by-layer degradation mechanism for the anode was proposed.展开更多
基金supported by the National Natural Science Foundation of China(21567008,21263005)the Yangfan Project of Guangdong Province+2 种基金the Natural Science Foundation of Jiangxi Province(20133BAB21003,20161BAB203090)the Landing Project of Science and Technology of Colleges and Universities in Jiangxi Province(KJLD14046)the Graduate Innovation Project of Jiangxi Province(YC2015-S293)~~
文摘Ag2S/Ag2WO4 composite microrods,with lengths of 0.2-1μm and diameters of 20-30 nm,were fabricated by a facile sonochemical route.The as-synthesized products were intensively investigated by a series of physicochemical characterizations,such as N2 physical adsorption,X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Fourier transform infrared spectroscopy,diffuser reflectance spectroscopy,X-ray photoelectron spectroscopy,photoluminescence spectroscopy and photocurrent response measurements.Ultrasonic irradiation yields an obvious improvement in the photocatalyst texture,for example,an increase in crystallinity and surface area.Moreover,sonochemically fabricated Ag2S/Ag2WO4 microrods display strong visible light absorption and a high transient photocurrent response.The produced intimate Ag2S/Ag2WO4interface between Ag2S and Ag2WO4 crystal phases largely promotes the separation of photogenerated holes and electrons.High photocatalytic activity and stability were obtained over Ag2S/Ag2WO4composite microrods.The dye degradation rate constant of Ag2S/Ag2WO4 was 4.7 times and 29.8times higher than that of bare Ag2WO4 and Ag2S,respectively.
基金supported by the National Natural Science Foundation of China(Grant No.51075087)the Funds from the State Key Laboratory of Fluid Power Transmission and Control,Zhejiang University,China(Grant Nos.GZKF-201107 and GZKF-201004)the Foundation from the China Scholarship Council(Grant No.2009612129)
文摘To explore the application of the characteristics of metallic microparticles, alternating current electric trapping of the SU-8 microrods coated with a thin gold layer by the chemical approach is investigated. Positive dielectrophoresis is used to absorb the gold-coated SU-8 microrods at the edge of the parallel electrodes, thereby forming chains to connect the electrodes. This is a fast automatic microcircuit formation process. Moreover, a non-charged molecule is modified on the surface of the gold-coated SU-8 microrod, and the modified microrods are controlled by the alternating electric field to form a number of chains. The different chains between the parallel electrodes consist of various parallel circuits. In order to compare these chains with different electric surfaces, the impedances of the metallic and modified microrods are measured and compared, and the results show that the gold-coated microrods act as pure resistors, while the microrods functionalized by a non-charged molecule behave as good capacitors.
基金Supported by National Natural Science Foundation of China(Grant No.51305106)The State Key Lab of Fluid Power Transmission and Control,Zhejiang University of China(Grant No.GZKF-201107)
文摘Microfluidics is a promising system for the manipulation of micro-nano particles and fluids. In this platform, alternating current （AC） electric field is usual an effective tool for the general particles control. However, traditional work paid more attention on the regular spherical particles with no obvious distinction when rotating, resulting in imprecise rotation speed calculation. In essence, non-spherical especially biocompatible particles are not only important for biology application but also significant for obtaining accurate rotating results. Hence, in this paper, SU-8, one of the most biocompatible materials was selected as the manipulation object. AC electric field is employed to rotate SU-8 microrods, in order to obtain a controllable rotation angle for both the accurate experimental results and biosensor applications. Firstly, Clausius-Mossotti（CM） factors frequency spectra with different surface conductance and medium conductivities are presented, thereby the theoretical formula is carried out, including both the torque and rotation velocity expressions of SU-8 microrods. Moreover, simulations for the electric field distribution are developed, indicating the rotating direction. Secondly, the quadrupole electrodes are used to generate rotating electric field, and the electrorotation of SU-8 microrods in different medium is carried out, showing that the particles rotate in the opposite direction of the electric field, meanwhile, the peak frequency increases with the conductivity increases. Finally, the experimental results are discussed and compared with theoretical analysis, and the comparison result shows that they have a good agreement. This work proposes an effective and controllable method to rotate microrods, showing extend application potentials in microelectronics and biosensors.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61475035 and 61275054the Science and Technology Support Program of Jiangsu Province under Grant No BE2016177the Collaborative Innovation Center of Suzhou Nano Science and Technology
文摘ZnO microrods are synthesized using the vapor phase transport method, and the magnetron sputtering is used to decorate the A1 nanoparticles （NPs） on a single ZnO microrod. The micro-PL and I-V responses are measured before and after the decoration orAl NPs. The FDTD stimulation is also carried out to demonstrate the optical field distribution around the decoration of Al NPs on the surface of a ZnO microrod. Due to an implementation of AI NPs, the ZnO microrod exhibits an improved photoresponse behavior. In addition, AI NPs induced localized surface plasmons （LSPs） as well as improved optical field confinement can be ascribed to an enhancement of ultraviolet （UV） response. This research provides a method for improving the responsivity of photodetectors.
基金Project(0061)supported by the Doctorate Foundation of Nanchang University,ChinaProject(2006015)supported by the Center for Analysis and Testing,Nanchang University,China
文摘Tetrapod-shaped ZnO whiskers and microrods were synthesized in one crucible by thermal evaporation of Zn/C mixtures at 930 ℃ in air without any catalyst.The digital camera,optical microscopy,scanning electron microscopy,energy dispersive X-ray spectroscopy,and X-ray diffraction techniques were used to study the morphologies and crystal structures of these tetrapod-shaped ZnO microcrystals.The results show that these two types of ZnO tetrapods are grown at different heights within the same crucible.The legs of these tetrapod-shaped ZnO crystals are hexagonally faceted.Some tetrapod-shaped ZnO whiskers show hierarchical structures.A short button-like hexagonal ZnO microcrystal is observed at the triple junctions of some tetrapod-shaped ZnO whiskers.The tetrapod-shaped ZnO microrods are capped by two sets of hexagonal pyramids with two different groups of crystal planes for the surfaces.These two types of tetrapod-shaped ZnO microcrystals have different side faces and aspect ratio,which are believed to be the result of their different growth behaviors.The octa-twin model was used to discuss the different growth behaviors of these two types of ZnO tetrapods.The crystal planes of the legs and the pyramids were determined.
基金Supported by the National Natural Science Foundation of China（No.21475042）, the Scientific Research Fund of Hunan Pro- vincial Education Department, China（No.12B077）, the Open Fund Project of State Key Laboratory of Chemo/Biosensing and Chemometrics in Hunan University, China（No.201103） and the Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province, China.
文摘New lanthanide metal-organic framework（MOF） nano/microrods, [C4mim]Cl-Eu-MOF, [C8mim]Cl-Eu- MOF and [C12mim]Cl-Eu-MOF, were conveniently synthesized via an ionic liquid-assisted hydrothermal method and characterized by means of powder X-ray diffraction（XRD）, Fourier transform infrared spectroscopy（FTIR）, thermo- gravimetric analysis（TG） and transmission electron microscopy（TEM）. The obtained nano/microrods with low sur- face areas were efficient for the removal of Congo red（CR） from aqueous solutions. Under the optimum conditions, [C4mim]Cl-Eu-MOF with a specific surface area of 5.1 m^2/g exhibited an ultrahigh adsorption capacity of 2606 mg/g toward CR. Notably, the adsorption efficiency of [C4mim]Cl-Eu-MOF for CR via nano/microscale stacking can be directly demonstrated by TEM. In-depth understanding of CR removal by [C4mim]Cl-Eu-MOF nano/microrods was also supported by FTIR, Raman spectroscopy and zeta potential analyses.
基金supported by National Natural Science Foundation of China(Grant No.51602184)Natural Science Foundation of Shaanxi Province(Grant no.2020JM-505)the Academic Talent Introduction Program of SUST(134080056)。
文摘The morphology of MAX phase powders significantly influences their microwave absorption properties.However,the traditional synthesis via solid-state reactions produces irregular powders,and the preparation of MAX phase powders with specific morphology remains a challenge.Herein,(VTiCr)Al C MAX phase microrods were fabricated for the first time in NaCl/KCl molten salts using vanadium,titanium,chromium,aluminum,and short carbon fibers as precursors.It was found that despite acting as a carbon source,carbon fibers also acted as sacrificial templates.By adjusting the molar ratio of metal powders and short carbon fibers,a series of carbon fiber@(V_(0.8)Ti_(0.1)Cr_(0.1))_(2)AlC microrods with core-sheath structure were also obtained.Carbon fiber@(V_(0.8)Ti_(0.1)Cr_(0.1))_(2)AlC microrods with a molar ratio of 8:2 showed the optimum microwave absorption performance.The reflection loss(RL)value reached up to–63.26 d B at 2.40 mm,and the effective absorption bandwidth(EAB)was about 5.28 GHz with a thickness of2.02 mm.Based on the electromagnetic parameter analysis and theoretical simulation,the enhanced microwave absorption performance was attributed to the synergistic effect of different factors like dielectric loss,magnetic loss,multiple reflection,and scattering.This work offers a facile route to modulate the morphology of MAX phase powders and may accelerate its application as microwave absorbers.
基金supported by the National Natural Science Foundation of China (No. U1904215)the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions (TAPP)+1 种基金Natural Science Foundation of Jiangsu Province (No. BK20200044)Excellent doctoral dissertation of Yangzhou University and the Postgraduate Research & Practice Innovation Program of Jiangsu Province (No. KYCX19_2099)。
文摘Developing metal-organic framework(MOF)-based materials with good cyclic stability is the key to their practical application. Fluorinated organic compounds are usually highly chemically stability due to the high electronegativity of fluorine. Also, the pillared-layer structures based on coordination bonds have better structure and thermal stability than those based on hydrogen bonds. Herein, the fluorinated pillared-layer [Ni(2,3,4,5-tetrafluorobenzoic acid)(4,4-bipyridine)]nMOF([Ni(TFBA)(Bpy)]n) materials were constructed through a facile room-temperature solution reaction and used as electrode materials for supercapacitors. Surprisingly, the size/morphology of Ni(TFBA)(Bpy)nMOFs could be adjusted by varying the synthesis time. Benefting from the short ion diffusion length, unique pillar-layer structure, and strong intercomponent synergy of organic ligands, the Ni(TFBA)(Bpy)nMOF microrods showed a higher electrochemical energy storage capability than bulk MOFs. At the same time, compared to the non-fluorinated [Ni(benzoic acid)(Bpy)]nMOFs(31.5% capacitance decay), the fluorinated Ni(TFBA)(Bpy)n MOFs have a higher cycle stability with only 2.6% capacitance loss after 5000 cycles at 3 m A/cm^(2).
文摘Cyclic voltammetry and chronopotentiometry have been used to study the Sb-doped Ti/SnO2 anodes prepared by magnetron sputtering. The results showed that magnetron sputtering condition influenced the surface morphology and the properties of the anodes. After the Ti substrate was tempered in Ar at 600 ℃ for 1 h, Till1.5 on the surface generated from the acid etching was replaced by needle-like TiO2. The SnO2 coating on the above Ti substrate by magnetron sputtering with post-annealing was comprised of microrod and different with the traditional Ti/ SnO2 anode. The accelerated service life test showed that the microrod SnO2 anode gained the longest service time. The anode exhibited oscillations in the chronopotentiometry curves, and the microrod SnO2 coating almost dissolved after the life test. A model of layer-by-layer degradation mechanism for the anode was proposed.
