International Journal of Applied Ceramic Technology
·
2017
·Vol. 15
·期 3
·742-750
·
IF 1.048
Caihui Feng,Fei Teng,Yang Xu,Yajun Zhang,Tiehu Fan,Tingting Lin
In this work, pure and Au-nanoparticle-decorated SnO 2 nanorods were prepared via a one-step hydrothermal method combined with a facile deposition process, and then characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The xylene-sensing performance of the nanorods was also investigated. The results show that Au nanoparticles with an average diameter of 4-6 nm were immobilized on the surface of rutile SnO 2 nanorods. As the amount of Au increased, the surface-adsorbed oxygen species gradually increased. The 12 mol% Au-SnO 2 nanorods exhibited the highest response to 50 ppm xylene, a lower operating temperature (279 to 255°C), favorable selectivity, and fast response-recovery speed (3 and 4 seconds, respectively). These properties made the fabricated nanorods good candidates for xylene detection. The possible mechanism for the enhanced xylene-sensing performance is discussed.
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JOURNAL OF POROUS MATERIALS
·
2016
·Vol. 24
·期 3
·591-599
·
IF 1.385
Li Yanyan,Na Wei,Wang Hua,Gao Wengui
A series of Au–CuO/SBA-15 catalysts with 1–3 wt% Au and 30 wt% CuO were successfully prepared for CO 2 hydrogenation to methanol by chemical reduction and the following impregnation. The influence of Au content on the physicochemical properties of Au–CuO/SBA-15 catalysts was investigated in terms of ICP-AES, N 2 physisorption, XRD, TEM, N 2 O titration, XPS and H 2 –TPR technique. The results showed that the as-prepared Au–CuO/SBA-15 catalysts exhibited higher catalytic activity than CuO/SBA-15 catalyst. 2 % Au–CuO/SBA-15 catalyst showed the best catalytic activity with 13.5 % methanol selectivity and 24.2 % CO 2 conversion for CO 2 hydrogenation to methanol. The addition of Au NPs played an important role in improving the catalytic activity for CO 2 hydrogenation to methanol, which may be attributed to the interaction between Au and CuO.
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ANALYST
·
2016
·Vol. 141
·期 10
·2970-2976
·
IF 4.033
Yanyan Li,Xiaoming Ma,Zhengming Xu,Meihua Liu,Zhenyu Lin,Bin Qiu,Longhua Guo,Guonan Chen
Seed-mediated synthesis of gold nanorods (AuNRs) has been widely used for diverse applications in the past decade. In this work, this synthetic process is demonstrated for multicolor biosensing for the first time. Our investigation reveals that ascorbic acid acts as a key factor to mediate the growth of AuNRs. This phenomenon is incorporated into the alkaline phosphatase (ALP)-enzyme-linked immunosorbent assay (ELISA) system based on the fact that ALP can catalyze the conversion of ascorbic acid–phosphate into ascorbic acid with high efficiency. This allows us to develop a multicolor ELISA approach for sensitive detection of disease biomarkers with the naked eye. We show the proof-of-concept multicolor ELISA for the detection of prostate-specific antigen (PSA) in human serum. The results show that different colors are presented in response to different concentrations of PSA, and a detection limit of 3 × 10−15 g mL−1 in human serum was achieved. The proposed multicolor ELISA could be a good supplement to conventional ELISA for POC diagnostics.
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ELECTROCHIMICA ACTA
·
2013
·
IF 3.777
Yan Tong,Zhicheng Li,Xiaofeng Lu,Liu Yang,Weining Sun,Guangdi Nie,Zhaojie Wang,Ce Wang
An electrochemical method for the detection of dopamine based on a glass carbon electrode modified with electrospun CeO 2 /Au composite nanofibers was investigated in this article. The CeO 2 /Au composite nanofibers were prepared by the electrospinning technique and then annealed in air. The CeO 2 /Au composite nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements. Cyclic voltammetry (CV) showed that the electrospun CeO 2 /Au composite nanofibers modified carbon glass electrode exhibited an excellent electrocatalytic response to the dopamine (DA). The detection limit (S/N = 3) was as low as 0.056 μM and the sensitivity could reach 127 μA mM −1 cm −2 . All these demonstrated that the electrospun CeO 2 /Au composite nanofibers were good electrocatalyst for the oxidation of dopamine.
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APPLIED SURFACE SCIENCE
·
2015
·
IF 2.711
Qianwen Lian,Ai Luo,Zhenzhen An,Zhuang Li,Yongyang Guo,Dongxia Zhang,Zhonghua Xue,Xibin Zhou,Xiaoquan Lu
A novel and uniform gold nanoparticles/tryptophan-functionalized graphene nanocomposite (AuNPs/Trp-GR) has been successfully fabricated by directly electrochemical depositing gold onto the surface of tryptophan-functionalized graphene (Trp-GR). The nanostructure of AuNPs/Trp-GR was characterized by using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). It was demonstrated that Au nanoparticles were well dispersed on the surface of Trp-GR which might attribute to the more binding sites provided by Trp-GR for the formation of Au nanoparticles. The electrocatalytic activity of the AuNPs/Trp-GR towards the dopamine (DA) was systematically investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimum conditions, a wide and valuable linear range (0.5–411 μM), a low detection limit (0.056 μM, S/N = 3), good repeatability and stability were obtained for the determination of DA. Furthermore, the modified electrode was successfully applied to real samples analysis.
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ACS Applied Materials & Interfaces
·
2013
·
IF 5.008
Guangju Zhou,Yun Yang,Shuhua Han,Wei Chen,Yunzhi Fu,Chao Zou,Lijie Zhang,Shaoming Huang
Au nanobipyramids (NBPs) are important nanostructures which attract much attention due to their unique structure, optical, and catalytic properties. The controlled synthesis of Au NBPs and corresponding mechanistic study are highly desirable for both fundamental research and practical applications. Herein, we demonstrate a strategy that large sized Au decahedra with well-defined shape act as seeds for growing NBPs. Furthermore, through using different sized decahedra seeds with edge from 25 to 49 nm, various sized NBPs can be easily prepared (longitudinal length from 110 to 210 nm; transverse length from 36 to 70 nm). Our study provides hard evidence for the growth of NBPs that they surely stem from the overgrowth on penta-twinned decahedra. Because these used large size seeds have well-defined shape and structure, the growth of the NBPs can be easily determined. Results show that the formation of NBPs is primarily determined by the molar ratio of Au3+ and Au seeds (MRAA). MRAA less than 4 only causes size enhancement and no significant shape change. In cases of MRAA higher than 4 and lower than 8, quasi-nanorods are produced. When MRAA range from 8 to 10, NBPs form and the yield is higher than 90%. The effect of reaction time and temperature also are vital to the growth of NBPs. These prepared NBPs are found to exhibit excellent surface enhanced Raman scattering (SERS) performance because of many present hotspots, edges, steps, and tips on their surfaces.
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DALTON TRANSACTIONS
·
2014
·Vol. 43
·期 26
·10057-10063
·
IF 4.097
Xin Yang,Junhai Wang,Dongyue Su,Qingdong Xia,Fang Chai,Chungang Wang,Fengyu Qu
Rapid and sensitive detection of 2,4,6-trinitrotoluene (TNT) and 4-nitrophenol (4-NP) has attracted considerable attention due to their wide applications as nitroaromatic explosive materials. A novel fluorescence method for TNT and 4-NP based on bovine serum albumin functionalized fluorescent gold nanoclusters (BSA Au-NCs) has been developed. The detection probe BSA Au-NCs can be used as a fluorescent probe for the sensitive and selective detection of TNT and 4-NP simultaneously. A good linearity of fluorescence detection using BSA Au-NCs as a fluorescent probe was observed for TNT and 4-NP concentrations in the range of 10−8–5 × 10−5 M and 10−9–5 × 10−5 M, with a detection limit of 10 nM and 1 nM, respectively. The high specificity of TNT and 4-NP with BSA Au-NCs interactions provided excellent selectivity towards detecting TNT and 4-NP over other relevant nitroaromatic compounds. This system can be applied to test strips to detect TNT and 4-NP with high sensitivity and selectivity. The vapour of TNT and 4-NP can be detected using BSA Au-NCs test paper within 1 min with a detection limit of 10 pM and 1 pM.
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Journal of Nanostructure in Chemistry
·
2014
·Vol. 4
·期 3
·1-8
·
IF 0
Li Lihua,Feng Dexiang,Fang Xian,Han Xiaowei,Zhang Yuzhong
In this work, we have developed a novel visual Hg 2+ sensor in aqueous solution using unmodified Au@Ag core–shell nanoparticles at room temperature, based on a redox reaction between Ag-shell and Hg 2+ . The prepared Au@Ag core–shell nanoparticles exhibited good monodispersity. In the presence of Hg 2+ , Hg 2+ was reduced into Hg (0) by Ag-shell, and deposited on the surface of Au-core to form Au–Hg alloys and caused nanoparticles aggregation, leading to the color changes of the solution from yellow to purplish red, and the surface plasmon resonance spectra of Au@Ag core–shell nanoparticles red shift. Under the optimal conditions, the visual sensor could selectively detect Hg 2+ as low as 0.4 µM with the naked eye and 5.0 nM by UV–vis spectra analysis methods. The designed sensor had several advantages: (1) the nanoparticles surface need not be functionalized. (2) The color change of the solution was in 2 s and could easily be observed with naked eyes. The visual sensor had been applied to detection of Hg 2+ in tap and lake water, which obtained satisfied result.
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ANALYTICAL LETTERS
·
2014
·
IF 1.019
Zhong-Xia Wang,Shou-Nian Ding,Ezzaldeen Younes Jomma Narjh
A simple and label-free fluorescent assay for the sensitive determination of biological thiols was developed using Au@Ag nanoclusters. The sensing approach was based on the strong affinity of thiols to silver on the surface of the nanoclusters. In the presence of thiol-containing amino acids, the fluorescence of the Au@Ag nanoclusters was quenched due to the formation of a non-fluorescent coordination complex via the robust Ag-S bond, which allowed the determination of thiol-containing amino acids in a very simple and rapid way. Under the optimal conditions, an excellent linear relationship was present due to quenching of the Au@Ag nanoclusters over cysteine concentrations between 20 nM and 80 µM with a low detection limit of 5.87 nM. Glutathione was determined between 2 µM and 70 µM with a detection limit of 1.01 µM. In addition, the results reveal that the fluorescent assay has excellent selectivity toward thiol-containing amino acids compared to non-thiol containing amino acids. Moreover, the assay was successfully used to determine cysteine in human plasma, and thus Au@Ag nanoclusters are a suitable fluorescent probe for biological applications.
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ANALYST
·
2015
·Vol. 140
·期 6
·1913-1920
·
IF 4.107
Cong Li,Jingyu Zhao,Xiaoyi Yan,Yue Gu,Weilu Liu,Liu Tang,Bo Zheng,Yaru Li,Ruixue Chen,Zhiquan Zhang
Electrochemical detection of dopamine (DA) plays an important role in medical diagnosis. In this paper, tremella-like graphene–Au (t-GN–Au) composites were synthesized by a one-step hydrothermal method for selective detection of DA. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy were used to characterize as-prepared t-GN–Au composites. The t-GN–Au composites were directly used for the determination of DA via cyclic voltammetry (CV) and the chronoamperometry (CA) technique. CA measurement gave a wide linear range from 0.8 to 2000 μM, and the detection limit of 57 nM (S/N = 3) for DA. The mechanism and the heterogeneous electron transfer kinetics of the DA oxidation were discussed in the light of rotating disk electrode (RDE) experiments. Moreover, the modified electrode was applied to the determination of DA in human urine and serum samples.
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INORGANIC CHEMISTRY COMMUNICATIONS
·
2024
·
IF 4.4
Han Sun,Yiting Wang,Fang Xu,Sui-Jun Liu,Haiping Huang
The methanol oxidation reaction (MOR) serves as a critical determinant of the energy conversion efficiency within direct methanol fuel cells (DMFC). Consequently, the development of cost-effective and efficient electrocatalysts is paramount for enhancing energy conversion efficiency associated with MOR. The nanomaterials with diverse metal atomic molar ratio of (Ni:W) were synthesized via hydrothermal method for the immobilization of Au nanoparticles (Au NPs) onto the sample surface. The crystal structure of nanocomposites was confirmed through X-ray diffraction (XRD), and transmission electron microscopy (TEM) images depicted a specific surface topography. The catalytic performance of the synthesized catalysts in the MOR was assessed through electrochemical analysis. Notably, catalyst with the Ni:W atomic ratio of 2:1, displayed superior electrocatalytic performance when compared to catalysts possessing other different metal ratios. Moreover, chronoamperometry tests conducted over 7200 s and Tafel slope analysis demonstrated the enduring activity and strong resistance to toxicity of the synthesized catalysts. These results highlight the potential of nickel-tungstate bimetallic oxide as an exceptionally efficient catalyst in the field of electrocatalysis.
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INORGANIC CHEMISTRY
·
2024
·
IF 4.3
Lecheng Zhao,Jiaxin Luo,Shutian Wang,Jiayu Sun,Hongyu Chen,Yawen Wang
Amine ligands have been widely applied as morphology-directing reagents in nanostructure synthesis. In this work, we explored the application of the amine ligands in the active surface growth mechanism in place of the strong thiolated ligands. Despite being weaker compared to the thiols, amine ligands such as aniline were also shown to be capable of facilitating the template-less electrodeposition of Au nanowires (NWs) on the substrate via the active surface growth mechanism. Given the close binding difference between the amine-grafted substrate and the ligands, substrate functionalization becomes critically important for effective construction of the active surface and the growth of the nanowires. Additionally, the growth with the amine ligands took place at more positive reduction potentials and is less prone to splitting and bundle formation. A systematic generality study revealed that besides the aromatic amines, long-chain aliphatic amines were also capable of facilitating nanowire growth. Given the weak binding affinity of the amine ligands, the Au NWs are readily accessible for further processing to generate sophisticated one-dimensional structures. As a demonstration, tandem electrodeposition was performed to directly obtain coaxial core–shell Au@Pt NWs with adjustable length, diameter, and shell thickness.
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