Ag dendritic nanostructures were synthesized on fluorine-doped tin oxide covered glass sub- strates by the electrodeposition method. Results demonstrate that the size, diameter, crys- tallinity, and branch density of ...Ag dendritic nanostructures were synthesized on fluorine-doped tin oxide covered glass sub- strates by the electrodeposition method. Results demonstrate that the size, diameter, crys- tallinity, and branch density of the Ag dendrites can be controlled by the applied potential, the surfactants and the concentration of AgNO3. Three kinds of typical silver dendrites were applied as substrates of the surface enhanced Raman scattering （SERS） and one of them was able to clearly detect rhodamine 6G concentrations up to 0.1 nmol/L. The differences of the SERS spectra at these Ag dendrites confirmed that the shapes and interparticle spacings have great effect on Raman enhancement, especially the interparticle spacings.展开更多
We present a general approach to fabricate metal/TiO2 core/shell nanorod structures by twostep electrodeposition. Firstly, TiO2 nanotubes with uniform wall thickness are prepared in anodic aluminum oxide （AAO） membr...We present a general approach to fabricate metal/TiO2 core/shell nanorod structures by twostep electrodeposition. Firstly, TiO2 nanotubes with uniform wall thickness are prepared in anodic aluminum oxide （AAO） membranes by electrodeposition. The wall thickness of the nanotubes could be easily controlled by modulating the deposition time, and their outer diameter and length are only limited by the channel diameter and the thickness of the AAO membranes, respectively. The nanotubes＇ tops prepared by this method are open, while the bottoms are connected directly with the Au film at the back of the AAO membranes. Secondly, Pd, Cu, and Fe elements are filled into the TiO2 nanotubes to form core/shell structures. The core/shell nanorods prepared by this two-step process are high density and free-standing, and their length is dependent on the deposition time.展开更多
Morphological evolution of Pd nanoparticles was studied in a solution-phase synthesis using cetyltrimethylammonium bromide （CTAB） and CTAB/sodium citrate mixture as capping agents, respectively. The morphological di...Morphological evolution of Pd nanoparticles was studied in a solution-phase synthesis using cetyltrimethylammonium bromide （CTAB） and CTAB/sodium citrate mixture as capping agents, respectively. The morphological diversity of Pd nanoparticles is the combined effect of different Pd twinned seeds formed in the nucleation stage and selectively enlarging one set of crystallographic facets in the growth stage, both of which can be affected by the concentrations of CTAB. Through changing the concentrations of CTAB and sodium ascorbate, Pd nanoparticles with different shapes were obtained. When citrate ions were introduced to manipulate the nucleation and growth process, star-shaped icosahedra and nanorods with pentagram cross-sections were obtained. Pd nanoparticles with different shapes have quite different surface plasmon resonance and surface-enhanced Raman scattering properties.展开更多
TiO2 nanostructures were fabricated by a reaction of Ti foils in H2O2 solution at mild temperature, Porous TiO2 nanostructurcs, well adhered to Ti foil surfaces, were formed at 80 ℃ in 10 rain, and then flower- like ...TiO2 nanostructures were fabricated by a reaction of Ti foils in H2O2 solution at mild temperature, Porous TiO2 nanostructurcs, well adhered to Ti foil surfaces, were formed at 80 ℃ in 10 rain, and then flower- like and rod nanostructures formed in succession after a longer reaction time. Samples prepared at 80 ℃ for 4 h arc amorphous, and anatase-dominated crystal phase emerged in the sample prepared for as long as 10 h. Almost pure anatase phase were obtained in TiO2 nanostructures by annealing the samples at a temperature of 300 ℃. Photoeatalysis of the TiO2 nanostructures was characterized by the degradation of RhB dye molecules in an aqueous solution exposed to ultraviolet light. Results show a 7 cm^2 annealed TiO2 flower-like nanostrueture having the degradation rate of RhB as fast as 29.8 times that of the dye solution exposed to ultraviolet light alone.展开更多
Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since ...Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.展开更多
文摘Ag dendritic nanostructures were synthesized on fluorine-doped tin oxide covered glass sub- strates by the electrodeposition method. Results demonstrate that the size, diameter, crys- tallinity, and branch density of the Ag dendrites can be controlled by the applied potential, the surfactants and the concentration of AgNO3. Three kinds of typical silver dendrites were applied as substrates of the surface enhanced Raman scattering （SERS） and one of them was able to clearly detect rhodamine 6G concentrations up to 0.1 nmol/L. The differences of the SERS spectra at these Ag dendrites confirmed that the shapes and interparticle spacings have great effect on Raman enhancement, especially the interparticle spacings.
基金Supported by Natural Science Foundation of China(10574122,50772110,50721091)the National Basic Research Program of China(2006CB922000,2007CB925202,2009CB939901)KJCX2.YW.W06-3 of CAS
基金This work is supported by the National Natural Science Foundation of China （No.10574122, No.50772110, No.50721091） and the National Basic Research Program of China （No.2011CB921400, No.2007CB925202, No.2009CB939901）.
文摘We present a general approach to fabricate metal/TiO2 core/shell nanorod structures by twostep electrodeposition. Firstly, TiO2 nanotubes with uniform wall thickness are prepared in anodic aluminum oxide （AAO） membranes by electrodeposition. The wall thickness of the nanotubes could be easily controlled by modulating the deposition time, and their outer diameter and length are only limited by the channel diameter and the thickness of the AAO membranes, respectively. The nanotubes＇ tops prepared by this method are open, while the bottoms are connected directly with the Au film at the back of the AAO membranes. Secondly, Pd, Cu, and Fe elements are filled into the TiO2 nanotubes to form core/shell structures. The core/shell nanorods prepared by this two-step process are high density and free-standing, and their length is dependent on the deposition time.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.i0574122, No.50772110, and No.50721091）, the National Basic Research Program of China （No.2006CB922000, No.2007CB925202, and No.2009CB939901）, and the Fund of the Chinese Academy of Sciences for Key Topics in Innovation Engineering （KJCX2.YW.W06-3）
文摘Morphological evolution of Pd nanoparticles was studied in a solution-phase synthesis using cetyltrimethylammonium bromide （CTAB） and CTAB/sodium citrate mixture as capping agents, respectively. The morphological diversity of Pd nanoparticles is the combined effect of different Pd twinned seeds formed in the nucleation stage and selectively enlarging one set of crystallographic facets in the growth stage, both of which can be affected by the concentrations of CTAB. Through changing the concentrations of CTAB and sodium ascorbate, Pd nanoparticles with different shapes were obtained. When citrate ions were introduced to manipulate the nucleation and growth process, star-shaped icosahedra and nanorods with pentagram cross-sections were obtained. Pd nanoparticles with different shapes have quite different surface plasmon resonance and surface-enhanced Raman scattering properties.
基金supported by the National Natural Science Foundation of China(No.10574122 and No.60376008).
文摘TiO2 nanostructures were fabricated by a reaction of Ti foils in H2O2 solution at mild temperature, Porous TiO2 nanostructurcs, well adhered to Ti foil surfaces, were formed at 80 ℃ in 10 rain, and then flower- like and rod nanostructures formed in succession after a longer reaction time. Samples prepared at 80 ℃ for 4 h arc amorphous, and anatase-dominated crystal phase emerged in the sample prepared for as long as 10 h. Almost pure anatase phase were obtained in TiO2 nanostructures by annealing the samples at a temperature of 300 ℃. Photoeatalysis of the TiO2 nanostructures was characterized by the degradation of RhB dye molecules in an aqueous solution exposed to ultraviolet light. Results show a 7 cm^2 annealed TiO2 flower-like nanostrueture having the degradation rate of RhB as fast as 29.8 times that of the dye solution exposed to ultraviolet light alone.
文摘Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.
