Au hierarchical architectures with special morphology and structures are strongly desired in varied applications.Herein,a simple synthesis method was developed for the one-step preparation of Au micronails(MNs)at the ...Au hierarchical architectures with special morphology and structures are strongly desired in varied applications.Herein,a simple synthesis method was developed for the one-step preparation of Au micronails(MNs)at the planar liquid-liquid interface under mild conditions.The well-defined Au MNs were grown and constructed at CHCl_(3)-H_(2)O interface at room temperature using aniline in CHCl_(3)as reducing agent and HAuCl_(4)in H_(2)O as precursor and no surfactant or seed is required.The intriguing Au MNs with rough surface consist of big heads and thin rods,just like iron nails in outline.Furthermore,through simple changing the reagent concentrations,the length and surface roughness of Au MNs can be adjusted conveniently.The effects of a series of factors on the morphology and structure of the products are studied in detail.With p-aminothiophenol as a molecular probe,the as-obtained Au MNs all exhibit dramatically improved surface enhanced Raman scattering sensitivity and high reproducibility,the enhancement factor and limit of detection of Au MNs are 5.4×10^(5)and 1.0×10^(-10),respectively.展开更多
The roles of temperature change in surface-enhanced Raman scattering(SERS)hotspots are important for understanding the plasmon-mediated selective oxidation of p-aminothiophenol in a SERS measurement. Here, we demonstr...The roles of temperature change in surface-enhanced Raman scattering(SERS)hotspots are important for understanding the plasmon-mediated selective oxidation of p-aminothiophenol in a SERS measurement. Here, we demonstrate that the temperature change in hotspots seriously influences the conversion of p-aminothiophenol on Au by employing variable-temperature SERS measurements. The conversion steadily and irreversibly increased when the temperature increased from 100 to 360 K. But the conversion decreased above 360 K, because this conversion was exothermic. This temperature-dependence conversion suggests that the temperature change in hotspots originated from the photothermal effect should be coupled to the hot-electron effect in promoting the selective oxidation of p-aminothiophenol.展开更多
Nanoscale noble metals can exhibit excellent photochemical and photophysical properties, due to surface plasmon resonance(SPR) from specifically collective electronic excitations on these metal surfaces. The SPR effec...Nanoscale noble metals can exhibit excellent photochemical and photophysical properties, due to surface plasmon resonance(SPR) from specifically collective electronic excitations on these metal surfaces. The SPR effect triggers many new surface processes, including radiation and radiationless relaxations. As for the radiation process, the SPR effect causes the significant focus of light and enormous enhancement of the local surface optical electric field, as observed in surface-enhanced Raman spectroscopy(SERS) with very high detection sensitivity(to the single-molecule level). SERS is used to identify surface species and characterize molecular structures and chemical reactions. For the radiationless process, the SPR effect can generate hot carriers, such as hot electrons and hot holes, which can induce and enhance surface chemical reactions. Here, we review our recent work and related literature on surface catalytic-coupling reactions of aromatic amines and aromatic nitro compounds on nanostructured noble metal surfaces. Such reactions are a type of novel surface plasmon-enhanced chemical reaction. They could be simultaneously characterized by SERS when the SERS signals are assigned. By combining the density functional theory(DFT) calculations and SERS experimental spectra, our results indicate the possible pathways of the surface plasmonenhanced photochemical reactions on nanostructures of noble metals. To construct a stable and sustainable system in the conversion process of the light energy to the chemical energy on nanoscale metal surfaces, it is necessary to simultaneously consider the hot electrons and the hot holes as a whole chemical reaction system.展开更多
基金supported by Natural Science Foundation of Henan Province(grant Nos.242300420187,222300420146).
文摘Au hierarchical architectures with special morphology and structures are strongly desired in varied applications.Herein,a simple synthesis method was developed for the one-step preparation of Au micronails(MNs)at the planar liquid-liquid interface under mild conditions.The well-defined Au MNs were grown and constructed at CHCl_(3)-H_(2)O interface at room temperature using aniline in CHCl_(3)as reducing agent and HAuCl_(4)in H_(2)O as precursor and no surfactant or seed is required.The intriguing Au MNs with rough surface consist of big heads and thin rods,just like iron nails in outline.Furthermore,through simple changing the reagent concentrations,the length and surface roughness of Au MNs can be adjusted conveniently.The effects of a series of factors on the morphology and structure of the products are studied in detail.With p-aminothiophenol as a molecular probe,the as-obtained Au MNs all exhibit dramatically improved surface enhanced Raman scattering sensitivity and high reproducibility,the enhancement factor and limit of detection of Au MNs are 5.4×10^(5)and 1.0×10^(-10),respectively.
基金financially supported by the National Natural Science Foundation of China (Nos.21872094,21991152,and21991150)a ShanghaiTech University Start-Up grant。
文摘The roles of temperature change in surface-enhanced Raman scattering(SERS)hotspots are important for understanding the plasmon-mediated selective oxidation of p-aminothiophenol in a SERS measurement. Here, we demonstrate that the temperature change in hotspots seriously influences the conversion of p-aminothiophenol on Au by employing variable-temperature SERS measurements. The conversion steadily and irreversibly increased when the temperature increased from 100 to 360 K. But the conversion decreased above 360 K, because this conversion was exothermic. This temperature-dependence conversion suggests that the temperature change in hotspots originated from the photothermal effect should be coupled to the hot-electron effect in promoting the selective oxidation of p-aminothiophenol.
基金financially supported by the National Natural Science Foundation of China(21321062,21373172)
文摘Nanoscale noble metals can exhibit excellent photochemical and photophysical properties, due to surface plasmon resonance(SPR) from specifically collective electronic excitations on these metal surfaces. The SPR effect triggers many new surface processes, including radiation and radiationless relaxations. As for the radiation process, the SPR effect causes the significant focus of light and enormous enhancement of the local surface optical electric field, as observed in surface-enhanced Raman spectroscopy(SERS) with very high detection sensitivity(to the single-molecule level). SERS is used to identify surface species and characterize molecular structures and chemical reactions. For the radiationless process, the SPR effect can generate hot carriers, such as hot electrons and hot holes, which can induce and enhance surface chemical reactions. Here, we review our recent work and related literature on surface catalytic-coupling reactions of aromatic amines and aromatic nitro compounds on nanostructured noble metal surfaces. Such reactions are a type of novel surface plasmon-enhanced chemical reaction. They could be simultaneously characterized by SERS when the SERS signals are assigned. By combining the density functional theory(DFT) calculations and SERS experimental spectra, our results indicate the possible pathways of the surface plasmonenhanced photochemical reactions on nanostructures of noble metals. To construct a stable and sustainable system in the conversion process of the light energy to the chemical energy on nanoscale metal surfaces, it is necessary to simultaneously consider the hot electrons and the hot holes as a whole chemical reaction system.
