Gold nanorods with aspect ratios of from 1 （particles） to 31.6 were synthesized by the seed-mediated method and packed in a highly ordered structure on a large scale on silicon substrates through capillary force ind...Gold nanorods with aspect ratios of from 1 （particles） to 31.6 were synthesized by the seed-mediated method and packed in a highly ordered structure on a large scale on silicon substrates through capillary force induced self-assembly behaviour during solvent evaporation. The gold nanorod surface exhibits a strong enhancing effect on Raman scattering spectroscopy. The enhancement of Raman scattering for two model molecules （2-naphthalenethiol and rhodamine 6C） is about 5-6 orders of magnitude. By changing the aspect ratio of the Au nanorods, we found that the enhancement factors decreased with the increase of aspect ratios. The observed Raman scattering enhancement is strong and should be ascribed to the surface plasmon coupling between closely packed nanorods, which may result in huge local electromagnetic field enhancements in those confined junctions.展开更多
Single crystalline boron nanocones are prepared by using a simple spin spread method in which Fe3O4 nanoparticles are pre-manipulated on Si（lll） to form catalyst patterns of different densities. The density of boron...Single crystalline boron nanocones are prepared by using a simple spin spread method in which Fe3O4 nanoparticles are pre-manipulated on Si（lll） to form catalyst patterns of different densities. The density of boron nanocones can be tuned by changing the concentration of catalyst nanoparticles. High-resolution transmission electron microscopy analysis shows that the boron nanocone has a β-tetragonal structure with good crystallization. The field emission behaviour is optimal when the spacing distance is close to the nanocone length, which indicates that this simple spin spread method has great potential applications in electron emission nanodevices.展开更多
The single crystalline palladium nanocubes with an average size of 7 nm were prepared in the presence of poly （vinyl pyrrolidone） （PVP） and KBr using the polyol method. The as-prepared Pd nanocubes were highly uni...The single crystalline palladium nanocubes with an average size of 7 nm were prepared in the presence of poly （vinyl pyrrolidone） （PVP） and KBr using the polyol method. The as-prepared Pd nanocubes were highly uniform in both size and shape. The ordered packing structures including monolayer and multilayer can be fabricated via the rate-controlled evaporation of solution solvent. The electrochemical catalytic activity of these Pd nanocubes towards methanol oxidation was found to be higher than that of spherical Pd nanoparticles of similar size.展开更多
Monodisperse Au Pd bimetallic nanoparticles（NPs） with different compositions are synthesized by using oleylamine（OAm） as reducing reagent, stabilizer, and solvent. To obtain Au Pd solid solution NPs, Pd–OAm and A...Monodisperse Au Pd bimetallic nanoparticles（NPs） with different compositions are synthesized by using oleylamine（OAm） as reducing reagent, stabilizer, and solvent. To obtain Au Pd solid solution NPs, Pd–OAm and Au–OAm precursors are firstly prepared by mixing OAm with Palladium（II） acetylacetonate（Pd（acac）2） and HAu Cl4, respectively. Then Pd–OAm and Au–OAm precursor solutions are injected into a hot oleylamine solution to form Au Pd NPs. The size of these NPs ranges from 6.0 to 8.0 nm and the composition is controlled by varying the precursor ratio. The Au Pd NPs are loaded onto reduced graphene oxide（RGO） sheets to make catalysts. Alloy NPs show high electrocatalytic activity and stability toward methanol oxidation in the alkaline media. Their catalytic activity for methanol oxidation is found to be dependent on the NP composition. As the Pd component increases, the peak current densities during the forward scan gradually increase and reach the maximum at Au Pd2. The enhancement of alloy NPs for methanol oxidation can be attributed to a synergistic effect of Au and Pd on the surface of alloy NPs.展开更多
Monodisperse Au-Fe3O4 heterodimeric nanoparticles （NPs） were prepared by injecting precursors into a hot reaction solution. The size of Au and Fe3O4 particles can be controlled by changing the injection temperature....Monodisperse Au-Fe3O4 heterodimeric nanoparticles （NPs） were prepared by injecting precursors into a hot reaction solution. The size of Au and Fe3O4 particles can be controlled by changing the injection temperature. UVis spectra show that the surface plasma resonance band of Au-Fe3O4 heterodimeric NPs was evidently red-shifted compared with the resonance band of Au NPs of similar size. The as-prepared heterodimeric Au-Fe3O4 NPs exhibited superparamagnetic properties at room temperature. The Ag-Fe3O4 heterodimeric NPs were also prepared by this synthetic method simply using AgNO3 as precursor instead of HAuCl4. It is indicated that the reported method can be readily extended to the synthesis of other noble metal conjugated heterodimeric NPs.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No.50872147)the National High Technology Research and Development Program of China (Grant No.2007AA03Z305)the Special Doctoral Foundation of the Ministry of Education of China (Grant No.20775030)
文摘Gold nanorods with aspect ratios of from 1 （particles） to 31.6 were synthesized by the seed-mediated method and packed in a highly ordered structure on a large scale on silicon substrates through capillary force induced self-assembly behaviour during solvent evaporation. The gold nanorod surface exhibits a strong enhancing effect on Raman scattering spectroscopy. The enhancement of Raman scattering for two model molecules （2-naphthalenethiol and rhodamine 6C） is about 5-6 orders of magnitude. By changing the aspect ratio of the Au nanorods, we found that the enhancement factors decreased with the increase of aspect ratios. The observed Raman scattering enhancement is strong and should be ascribed to the surface plasmon coupling between closely packed nanorods, which may result in huge local electromagnetic field enhancements in those confined junctions.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50872147 and U0734003)the National High Technology Research and Development Program (Grant No. 2007AA03Z305)the National Basic Research Program of China(Grant No. 2007CB935503)
文摘Single crystalline boron nanocones are prepared by using a simple spin spread method in which Fe3O4 nanoparticles are pre-manipulated on Si（lll） to form catalyst patterns of different densities. The density of boron nanocones can be tuned by changing the concentration of catalyst nanoparticles. High-resolution transmission electron microscopy analysis shows that the boron nanocone has a β-tetragonal structure with good crystallization. The field emission behaviour is optimal when the spacing distance is close to the nanocone length, which indicates that this simple spin spread method has great potential applications in electron emission nanodevices.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60571045 and 50872147)the National High Technology Research and Development Program of China (Grant No. 2007AA03Z035)
文摘The single crystalline palladium nanocubes with an average size of 7 nm were prepared in the presence of poly （vinyl pyrrolidone） （PVP） and KBr using the polyol method. The as-prepared Pd nanocubes were highly uniform in both size and shape. The ordered packing structures including monolayer and multilayer can be fabricated via the rate-controlled evaporation of solution solvent. The electrochemical catalytic activity of these Pd nanocubes towards methanol oxidation was found to be higher than that of spherical Pd nanoparticles of similar size.
基金Project supported by the National Natural Science Foundation of China(Grant No.61335006)the National Basic Research Program of China(Grant No.2013CBA01603)
文摘Monodisperse Au Pd bimetallic nanoparticles（NPs） with different compositions are synthesized by using oleylamine（OAm） as reducing reagent, stabilizer, and solvent. To obtain Au Pd solid solution NPs, Pd–OAm and Au–OAm precursors are firstly prepared by mixing OAm with Palladium（II） acetylacetonate（Pd（acac）2） and HAu Cl4, respectively. Then Pd–OAm and Au–OAm precursor solutions are injected into a hot oleylamine solution to form Au Pd NPs. The size of these NPs ranges from 6.0 to 8.0 nm and the composition is controlled by varying the precursor ratio. The Au Pd NPs are loaded onto reduced graphene oxide（RGO） sheets to make catalysts. Alloy NPs show high electrocatalytic activity and stability toward methanol oxidation in the alkaline media. Their catalytic activity for methanol oxidation is found to be dependent on the NP composition. As the Pd component increases, the peak current densities during the forward scan gradually increase and reach the maximum at Au Pd2. The enhancement of alloy NPs for methanol oxidation can be attributed to a synergistic effect of Au and Pd on the surface of alloy NPs.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.60571045 and 50872147)the National High-Tech.Research and Development Program of China (Grant No.2007AA03Z035)
文摘Monodisperse Au-Fe3O4 heterodimeric nanoparticles （NPs） were prepared by injecting precursors into a hot reaction solution. The size of Au and Fe3O4 particles can be controlled by changing the injection temperature. UVis spectra show that the surface plasma resonance band of Au-Fe3O4 heterodimeric NPs was evidently red-shifted compared with the resonance band of Au NPs of similar size. The as-prepared heterodimeric Au-Fe3O4 NPs exhibited superparamagnetic properties at room temperature. The Ag-Fe3O4 heterodimeric NPs were also prepared by this synthetic method simply using AgNO3 as precursor instead of HAuCl4. It is indicated that the reported method can be readily extended to the synthesis of other noble metal conjugated heterodimeric NPs.
