Gold colloid was prepared by chemical reduction of hydrogen tetrachloroaurate, polyelectrolyte/gold nanoparticle/silica nanoparticie composite films were fabricated via an electrostatic self-assembly multilayer method...Gold colloid was prepared by chemical reduction of hydrogen tetrachloroaurate, polyelectrolyte/gold nanoparticle/silica nanoparticie composite films were fabricated via an electrostatic self-assembly multilayer method, and composite films of gold nanoparticle dispersed in silica matrix were formed by heat-treating the polyelectrolyte/gold nanoparticle/silica nanoparticle composite films to eliminate the polyelectrolyte. The obtained composite films were investigated with UV-vis, TEM, AFM and XRD. The results show that the self-assembly multilayer method is a promising process to produce composite films of gold nanoparticle-dispersed in organic and/or inorganic matrixes.展开更多
Amino-functionalized mesoporous silica thin films （MTFs） are produced using surface active agent F127,and then gold nanoparticles are introduced into the pore channels to prepare the Au/SiO 2 nanocomposite.After ass...Amino-functionalized mesoporous silica thin films （MTFs） are produced using surface active agent F127,and then gold nanoparticles are introduced into the pore channels to prepare the Au/SiO 2 nanocomposite.After assembling the gold,the amino-functionalized MTF undergoes some shrinkage but remains a periodic structure as demonstrated by X-ray diffraction （XRD） patterns.The nanocomposite shows an acute characteristic diffraction peak assigned to （111） plane of the face-centered-cubic structure of gold,indicating that gold nanoparticles crystallize well and grow in a preferred orientation in the pore channels.The surface plasma resonance （SPR） absorption peak near 570 nm undergoes a red-shift accompanied by a strengthening of intensity when HAuCl 4 is used to react with the amino groups on the internal pore surfaces for 4,6,and 8 h.The simulative results are consistent with the experimental ones shows that the absorption property of the Au/SiO 2 nanocomposite is influenced by the dipping time,which affects the size and volume fraction of embedded gold nanoparticles.展开更多
A new approach for the highly sensitive detection of dopamine by a novel composite film involving gold nanoparticles trapped in a negatively-charged fluorocarbon polymer (Nafion) on a glassy carbon (GC) electrode fabr...A new approach for the highly sensitive detection of dopamine by a novel composite film involving gold nanoparticles trapped in a negatively-charged fluorocarbon polymer (Nafion) on a glassy carbon (GC) electrode fabricated by a simple method is described. Gold nanoparticles with an average diameter of 2.3 nm ± 0.2 nm are dispersed throughout the whole Nafion film. The introduction of gold nanoparticles into the Nafion film not only gives a highly active electrode surface area but also increases the conductivity of the Nafion film and the resulting Au/Nafion/GC electrode combines the advantages of the properties of gold nanoparticles and the selective pre-concentration ability of Nafion. For positively charged dopamine, the results show a decrease in the redox peak separation and a high sensitivity. The oxidation peak current of dopamine was shown to vary linearly with dopamine concentration over a wide range from 0.4 to 50.0 μmol/L with a detection limit of 0.3 μmol/L. Negatively charged ascorbic acid shows no redox waves at concentrations up to 1.0 ×10-4 mol/L.展开更多
Nonanethiol capped gold nanoparticles were firstly used to modify the surface of MoO 3 thin films in order to fabricate the MoO 3/Au composite thin film. Absorption experiments and XPS measurements were used to invest...Nonanethiol capped gold nanoparticles were firstly used to modify the surface of MoO 3 thin films in order to fabricate the MoO 3/Au composite thin film. Absorption experiments and XPS measurements were used to investigate the effect of Au nanoparticles on the photochromic properties of the composite thin film. According to the XPS measurements, the binding energy for the valence band(O 2p ) of the composite thin films decreased. The experimental results of absorbance showed that the photochromic efficiency for the composite thin films became at least as two times as that of MoO 3 thin films. The mechanism of enhancement can be explained by the band energy theory of semiconductor. The Schottky barrier formed at the interface prolonged the electron hole pair separation lifetime and resulted in the enhancement of the photochromic efficiency.展开更多
In this work,the electrochemical oxidation of L-cysteine(CySH)was investigated on a composite film modified electrode with Au nanoparticles dispersed in the fluorocarbon polymer(Nafion).The excellent electrocatalytic ...In this work,the electrochemical oxidation of L-cysteine(CySH)was investigated on a composite film modified electrode with Au nanoparticles dispersed in the fluorocarbon polymer(Nafion).The excellent electrocatalytic effect on CySH oxidation was attributed to the role of Au nanoparticles.The voltammetric studies revealed two anodic peaks for the oxidation of CySH in the pH range of 2.0–8.0.The electrode was used to detect cysteine at pH 2.0 and pH 7.0.At pH 2.0,a determination range of 3.0–50.0?mol/L was obtained with the detection sensitivity of 22.7A/(mmol L1),while at pH 7.0,a determination range of 2.0–80.0mol/L was obtained with the detection sensitivity of 4.08A/(mmol L1).The detection limits were estimated to be as low as 1.0?mol/L at both pH 7.0 and pH 2.0.Additionally,at pH 7.0,the interferences of ascorbic acid and uric acid were reduced for the detection of cysteine.These made the Au/Nafion/GC electrode a promising candidate for efficient electrochemical sensors for the detection of CySH.展开更多
基金This work was supported by the Natural Science Foundation of Hubei Province(Project No.2000J002)
文摘Gold colloid was prepared by chemical reduction of hydrogen tetrachloroaurate, polyelectrolyte/gold nanoparticle/silica nanoparticie composite films were fabricated via an electrostatic self-assembly multilayer method, and composite films of gold nanoparticle dispersed in silica matrix were formed by heat-treating the polyelectrolyte/gold nanoparticle/silica nanoparticle composite films to eliminate the polyelectrolyte. The obtained composite films were investigated with UV-vis, TEM, AFM and XRD. The results show that the self-assembly multilayer method is a promising process to produce composite films of gold nanoparticle-dispersed in organic and/or inorganic matrixes.
基金supported by the Advanced Research Foundation of National University of Defense Technology under Grant No.JC08-02-08
文摘Amino-functionalized mesoporous silica thin films （MTFs） are produced using surface active agent F127,and then gold nanoparticles are introduced into the pore channels to prepare the Au/SiO 2 nanocomposite.After assembling the gold,the amino-functionalized MTF undergoes some shrinkage but remains a periodic structure as demonstrated by X-ray diffraction （XRD） patterns.The nanocomposite shows an acute characteristic diffraction peak assigned to （111） plane of the face-centered-cubic structure of gold,indicating that gold nanoparticles crystallize well and grow in a preferred orientation in the pore channels.The surface plasma resonance （SPR） absorption peak near 570 nm undergoes a red-shift accompanied by a strengthening of intensity when HAuCl 4 is used to react with the amino groups on the internal pore surfaces for 4,6,and 8 h.The simulative results are consistent with the experimental ones shows that the absorption property of the Au/SiO 2 nanocomposite is influenced by the dipping time,which affects the size and volume fraction of embedded gold nanoparticles.
基金support from the National Natural Science Foundation of China (Grant No. 20875008) is gratefully acknowledged
文摘A new approach for the highly sensitive detection of dopamine by a novel composite film involving gold nanoparticles trapped in a negatively-charged fluorocarbon polymer (Nafion) on a glassy carbon (GC) electrode fabricated by a simple method is described. Gold nanoparticles with an average diameter of 2.3 nm ± 0.2 nm are dispersed throughout the whole Nafion film. The introduction of gold nanoparticles into the Nafion film not only gives a highly active electrode surface area but also increases the conductivity of the Nafion film and the resulting Au/Nafion/GC electrode combines the advantages of the properties of gold nanoparticles and the selective pre-concentration ability of Nafion. For positively charged dopamine, the results show a decrease in the redox peak separation and a high sensitivity. The oxidation peak current of dopamine was shown to vary linearly with dopamine concentration over a wide range from 0.4 to 50.0 μmol/L with a detection limit of 0.3 μmol/L. Negatively charged ascorbic acid shows no redox waves at concentrations up to 1.0 ×10-4 mol/L.
文摘Nonanethiol capped gold nanoparticles were firstly used to modify the surface of MoO 3 thin films in order to fabricate the MoO 3/Au composite thin film. Absorption experiments and XPS measurements were used to investigate the effect of Au nanoparticles on the photochromic properties of the composite thin film. According to the XPS measurements, the binding energy for the valence band(O 2p ) of the composite thin films decreased. The experimental results of absorbance showed that the photochromic efficiency for the composite thin films became at least as two times as that of MoO 3 thin films. The mechanism of enhancement can be explained by the band energy theory of semiconductor. The Schottky barrier formed at the interface prolonged the electron hole pair separation lifetime and resulted in the enhancement of the photochromic efficiency.
基金supported by the National Natural Science Foundation of China(20875008)
文摘In this work,the electrochemical oxidation of L-cysteine(CySH)was investigated on a composite film modified electrode with Au nanoparticles dispersed in the fluorocarbon polymer(Nafion).The excellent electrocatalytic effect on CySH oxidation was attributed to the role of Au nanoparticles.The voltammetric studies revealed two anodic peaks for the oxidation of CySH in the pH range of 2.0–8.0.The electrode was used to detect cysteine at pH 2.0 and pH 7.0.At pH 2.0,a determination range of 3.0–50.0?mol/L was obtained with the detection sensitivity of 22.7A/(mmol L1),while at pH 7.0,a determination range of 2.0–80.0mol/L was obtained with the detection sensitivity of 4.08A/(mmol L1).The detection limits were estimated to be as low as 1.0?mol/L at both pH 7.0 and pH 2.0.Additionally,at pH 7.0,the interferences of ascorbic acid and uric acid were reduced for the detection of cysteine.These made the Au/Nafion/GC electrode a promising candidate for efficient electrochemical sensors for the detection of CySH.
