共查询到20条相似文献,搜索用时 46 毫秒
1.
Yaqing Liu 《Electrochimica acta》2005,51(4):605-610
Hyperbranched thin film (HTF) with amino and imino groups, which can accommodate PtCl62−, was synthesized with small organic molecules on gold substrate based on SN2 displacement reaction. Platinum nanoparticles (PtNPs) were in situ synthesized by electrochemically reduction of precursors, PtCl62−, within HTF. The prepared films were characterized by X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM). It was confirmed that densely packed PtNPs were prepared with a narrow size distribution. EIS indicated that HTF inhibits electron transfer slightly while Pt nanoparticles in the HTF enhanced the electron-transfer ability greatly. Cyclic voltammetry (CV) indicated that HTF containing PtNPs exhibited a remarkable electrocatalytic activity for the electrochemical reduction of dioxygen. The quantity of PtNPs could be expediently controlled by the thickness of HTF. So the catalytic ability can be tailored correspondingly. 相似文献
2.
Aniruddha S. Deshpande Ramdas B. Khomane Bhalchandra K. Vaidya Renuka M. Joshi Arti S. Harle Bhaskar D. Kulkarni 《Nanoscale research letters》2008,3(6):221-229
Sulfur nanoparticles were synthesized from hazardous H2S gas using novel biodegradable iron chelates in w/o microemulsion system. Fe3+–malic acid chelate (0.05 M aqueous solution) was studied in w/o microemulsion containing cyclohexane, Triton X-100 and n-hexanol as oil phase, surfactant, co-surfactant, respectively, for catalytic oxidation of H2S gas at ambient conditions of temperature, pressure, and neutral pH. The structural features of sulfur nanoparticles have
been characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive spectroscopy (EDS),
diffused reflectance infra-red Fourier transform technique, and BET surface area measurements. XRD analysis indicates the
presence of α-sulfur. TEM analysis shows that the morphology of sulfur nanoparticles synthesized in w/o microemulsion system
is nearly uniform in size (average particle size 10 nm) and narrow particle size distribution (in range of 5–15 nm) as compared
to that in aqueous surfactant systems. The EDS analysis indicated high purity of sulfur (>99%). Moreover, sulfur nanoparticles
synthesized in w/o microemulsion system exhibit higher antimicrobial activity (against bacteria, yeast, and fungi) than that
of colloidal sulfur. 相似文献
3.
Pulsed electrodeposition of Zn in the presence of surfactants 总被引:1,自引:0,他引:1
A. Gomes 《Electrochimica acta》2006,51(7):1342-1350
The preparation of Zn deposits has been performed by galvanostatic pulsed electrolysis, from acidic zinc sulphate solutions, on a stainless steel substrate. The influence of the surfactants (cetyl trimethyl ammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and octylphenolpoly(ethyleneglycolether)n, n = 10, Triton X-100) on the voltammetric behaviour, structural and morphological characteristics of the deposits have been investigated. The characterization of the samples was made by X-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS). The experimental data shows that the presence of surfactants affects the zinc deposition process. The electrodeposits are mainly composed by Zn with different texture, crystal shape and size (grain size ranging from 40 to 20 nm). The obtained results led us to conclude that the Zn deposits prepared in the absence of surfactants and in the presence of SDS are more crystalline and with a higher grain size than the ones obtained in the presence of CTAB and Triton X-100. These facts may be justified by the increase on the overpotential deposition as the electrochemical studies confirm.The XRD results show that the deposits prepared, in the absence of surfactant and in the presence of SDS, contain ZnSO4 and Zn4SO4(OH)6 as oxidation products. ZnO is also detected on the deposits obtained in the presence of CTAB and Triton X-100. 相似文献
4.
Tsung-Hsuan Tsai Soundappan Thiagarajan Shen-Ming Chen 《Journal of Applied Electrochemistry》2010,40(3):493-497
Au–Ag bimetallic nanoparticles have been fabricated by one-step simple electrochemical deposition method using ionic liquid
as green electrolyte (1-butyl-3-methylimidazolium tetrafluoro borate). Fabricated Au–Ag bimetallic nanoparticles have been
characterized using cyclic voltammetry (CV), FE-SEM, UV–vis spectroscopy, and X-ray diffraction (XRD) studies. The electrodeposited
Au–Ag bimetallic nanoparticles were found in the size range of 16–30 nm, respectively. This type of Au–Ag bimetallic nanoparticles
could be directly applied for the optoelectronic and biosensing applications. 相似文献
5.
Trang Thi Thuy Nguyen Seungjoo Haam Joon-Seo Park Sang-Wha Lee 《International journal of molecular sciences》2022,23(18)
The development of a strategy to investigate interfacial phenomena at lipid membranes is practically useful because most essential biomolecular interactions occur at cell membranes. In this study, a colorimetric method based on cysteine-encapsulated liposomes was examined using gold nanoparticles as a probe to provide a platform to report an enzymatic activity at lipid membranes. The cysteine-encapsulated liposomes were prepared with varying ratios of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and cholesterol through the hydration of lipid films and extrusions in the presence of cysteine. The size, composition, and stability of resulting liposomes were analyzed by scanning electron microscopy (SEM), dynamic light scattering (DLS), nuclear magnetic resonance (NMR) spectroscopy, and UV-vis spectrophotometry. The results showed that the increased cholesterol content improved the stability of liposomes, and the liposomes were formulated with 60 mol % cholesterol for the subsequent experiments. Triton X-100 was tested to disrupt the lipid membranes to release the encapsulated cysteine from the liposomes. Cysteine can induce the aggregation of gold nanoparticles accompanying a color change, and the colorimetric response of gold nanoparticles to the released cysteine was investigated in various media. Except in buffer solutions at around pH 5, the cysteine-encapsulated liposomes showed the color change of gold nanoparticles only after being incubated with Triton X-100. Finally, the cysteine-encapsulated liposomal platform was tested to report the enzymatic activity of phospholipase A2 that hydrolyzes phospholipids in the membrane. The hydrolysis of phospholipids triggered the release of cysteine from the liposomes, and the released cysteine was successfully detected by monitoring the distinct red-to-blue color change of gold nanoparticles. The presence of phospholipase A2 was also confirmed by the appearance of a peak around 690 nm in the UV-vis spectra, which is caused by the cysteine-induced aggregation of gold nanoparticles. The results demonstrated that the cysteine-encapsulated liposome has the potential to be used to investigate biological interactions occurring at lipid membranes. 相似文献
6.
Selim Alayoglu Simon K. Beaumont Fan Zheng Vladimir V. Pushkarev Haimei Zheng Viacheslav Iablokov Zhi Liu Jinghua Guo Norbert Kruse Gabor A. Somorjai 《Topics in Catalysis》2011,54(13-15):778-785
Cobalt and platinum?Ccobalt bimetallic alloy nanoparticles of uniform size distribution where prepared and supported on MCF-17 to produce a controlled and well-characterized model catalyst which was studied under reaction conditions during CO2 hydrogenation. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy was used to elucidate the oxidation state of the catalyst under reaction conditions while the effect of reducing H2 gas on the composition and structure of the bimetallic PtCo nanoparticles was measured using ambient pressure X-ray photoelectron spectroscopy (AP-XPS) and environmental transmission electron microscopy (ETEM). NEXAFS indicates that Pt aids the reduction of Co to its metallic state under relevant reaction conditions, while AP-XPS and ETEM indicate that Pt is enriched at the surface by exchange with subsurface layers which become Pt deficient??in agreement with the ??Pt-like?? selectivity seen during catalytic testing of these materials. 相似文献
7.
Young-Sam Jung Beomjin Yoo Min Ki Lim Seung Yong Lee Kang-Jin Kim 《Electrochimica acta》2009,54(26):6286-6291
The performance of a Ru(II) dye-sensitized nanocrystalline TiO2 solar cell (DSSC) with both Triton X-100 and water as additives in 3-methoxypropionitrile solutions is described. In the presence of these additives, the open-circuit voltage (Voc), fill factor and stability of the cell increased, while the short-circuit photocurrent density decreased compared to those found in their absence. Based on these changes, the DSSC yielded a higher solar-to-electricity conversion efficiency of 5.9%, compared to 5.3% for the cells fabricated without the additives. Furthermore, the addition of Triton X-100 to the water-added electrolyte was found to render the Ag metal corrosion resistant. 相似文献
8.
《Ceramics International》2017,43(17):15258-15265
Stable suspensions of spherical 10–15 nm superparamagnetic iron oxide nanoparticles (SPIONs) have been synthetized by co-precipitation, stabilized with citric acid, surface functionalized with aminopropyltriethoxysilane (APTES) and finally decorated with ultra-small gold nanoparticles (GNPs) by in situ reduction of a soluble gold salt (HAuCl4), obtaining well dispersed SPIONs-GNPs colloids.The morphology, size and stability of the SPIONs-GNPs suspensions have been controlled by adjusting the molar ratio of the reagents (Fe/HAuCl4 and Fe/APTES). The synthesis route differs from that typically found in literature, using tunable chelating layer modifications (such as citric acid and –NH2 groups) of the magnetic core, depositing GNPs on the amine-functionalized iron oxide surface without the use of a specific reducing agent, and tuning the process pH and temperature. An explanation of how the different chemical species involved in the synthesis route could be responsible for the reducing action has been provided. The SPIONs-GNPs colloids have been characterized after each synthesis step by Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM), energy-dispersive X-ray spectroscopy (EDXS), Fourier transform infrared spectroscopy (FTIR), ζ Potential measurements, magnetic measurements with a vibrating-sample magnetometer (VSM) and UV–VIS spectroscopy. The SPIONs-GNPs colloids showed magnetoplasmonic behaviors since they maintained the plasmonic properties of GNPs and the superparamagnetic response of iron oxide NPs. 相似文献
9.
Nano-sized rod like hydroxyapatite (HA) particles were synthesized using Ca(NO3)2·4H2O and (NH4)2HPO4 as precursors with varying contents of non-ionic surfactant viz., p-(1,1,3,3-tetramethylbutyl)phenoxypoly(oxyethylene)glycol (triton X-100) as organic modifer. The crystalline phase, chemical composition, surface area and morphology of the prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), BET surface area analysis, high resolution scanning electron microscopy (HRSEM) and transmission electron microscopy (TEM). The above studies indicate the presence of nanoscale hydroxyapatite (HA) phase. Triton X-100 does not appear to affect the crystallinity of the samples. Increase of BET surface area and the consequent decrease in particle size of HA were observed as a function of surfactant content. Probable mechanism for the role of the surfactant in the synthesis of nanoscale HA has also been discussed. 相似文献
10.
在水溶液/TritonX-100/正己醇/环己烷组成的反相微乳液中,以氯化钡和硫酸钠为原料,通过沉淀反应,制备出类球形BaSO4纳米颗粒,并通过XRD、SEM、TEM、FTIR对其进行表征。考察了三种反应方式、水/TritonX-100摩尔比(R)、反应物浓度以及助表面活性剂/表面活性剂摩尔比(P)对纳米BaSO4颗粒大小和形貌的影响。同时考察了R对微乳液液滴大小和粒径分布的影响,并通过动态光散射技术(DLS)对微乳液液滴进行测定。实验结果表明:室温条件下,采用双微乳液法,R=17.97,P在2.11~4.22之间是纳米BaSO4颗粒合成的最佳反应条件,反应物浓度对BaSO4颗粒的大小和形貌几乎没有影响。在该反应条件下,合成出的类球形BaSO4粒径为18~22 nm,产率可达87.5%。 相似文献
11.
Maryam Erfani Elias Saion Nayereh Soltani Mansor Hashim Wan Saffiey B. Wan Abdullah Manizheh Navasery 《International journal of molecular sciences》2012,13(11):14434-14445
Calcium borate nanoparticles have been synthesized by a thermal treatment method via facile co-precipitation. Differences of annealing temperature and annealing time and their effects on crystal structure, particle size, size distribution and thermal stability of nanoparticles were investigated. The formation of calcium borate compound was characterized by X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), and Thermogravimetry (TGA). The XRD patterns revealed that the co-precipitated samples annealed at 700 °C for 3 h annealing time formed an amorphous structure and the transformation into a crystalline structure only occurred after 5 h annealing time. It was found that the samples annealed at 900 °C are mostly metaborate (CaB2O4) nanoparticles and tetraborate (CaB4O7) nanoparticles only observed at 970 °C, which was confirmed by FTIR. The TEM images indicated that with increasing the annealing time and temperature, the average particle size increases. TGA analysis confirmed the thermal stability of the annealed samples at higher temperatures. 相似文献
12.
Barbara Ballarin Maria Cristina Cassani Erika Scavetta Domenica Tonelli 《Electrochimica acta》2008,53(27):8034-8044
The fabrication of gold attached organosilane-coated indium tin oxide AuNPs-MPTMS/ITO and AuNPs-APTES/ITO electrodes [MPTMS = 3-(mercaptopropyl)-trimethoxysilane, APTES = 3-(aminopropyl)-triethoxysilane, ITO = indium tin oxide] was carried out making use of a well-known two-step procedure and the role played by the -SH and -NH2 functional groups in the two electrodes has been examined and compared using different techniques. Information about particle coverage and inter-particle spacing has been obtained using trasmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) whereas, bulk surface properties have been probed with UV-vis spectroscopy, CV and electrochemical impedance spectroscopy (EIS). The catalytic activity of the two electrodes has been evaluated studying the electrooxidation of methanol in alkaline conditions. The results obtained show that the NH2 functionality in the APTES binder molecule favours the formation of isle-like Au nanoparticle aggregates that lead to both a higher electron transfer and electrocatalytic activity. 相似文献
13.
Inseok Jang Hui Jun Leong Seong-Geun Oh 《Korean Journal of Chemical Engineering》2016,33(5):1647-1652
Nanosized TiO2 particles were prepared through facile sol-gel reaction by using microwave-assisted method. To investigate the effects of surfactants on the formation of TiO2, various additives (PVP, Triton X-100 and P123) were employed. The diameter of synthesized titania spheres could be controlled from 105 to 380 nm. The TiO2 particles prepared with P123 triblock copolymer showed large surface area and high pore volume. It was attributed to the fact that the pore site, where the surfactant template initially existed, was generated upon calcination process. The characteristics of prepared TiO2 nanoparticles were analyzed by using FE-SEM, TEM, XRD, FT-IR and N2 adsorption-desorption. As an application of prepared composites for water treatment, their photocatalytic performances for the degradation of methylene blue dye were examined by using UV-vis spectrophotometer under room light irradiation. The prepared TiO2 particles with Triton X-100 and P123 exhibited higher performance for methylene blue photo-degradation than that of P25. It was attributed to the effects of large specific surface area and high porosity. 相似文献
14.
Erdem Tevfik Ozdemir Serdar Yildirim Berk Ozler Tuncay Dikici Mustafa Erol Metin Yurddaskal 《International Journal of Applied Ceramic Technology》2023,20(6):3775-3785
In this study, manganese ferrite (MnFe2O4) nanoparticles were produced through flame spray pyrolysis (FSP). To investigate the effects of heat treatment, the nanoparticles were annealed between 400 and 650°C for 4 h in air in a comparative manner. The structural, chemical, morphological, and magnetic properties of the nanoparticles were evaluated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), dynamic light scattering (DLS), and vibrating sample magnetometry (VSM), respectively. The XRD results showed that the nanoparticles synthesized by the FSP method exhibited the MnFe2O4 spinel ferrite structure. The annealing process led to the decomposition of MnFe2O4 into various phases. According to the morphological analysis, the as-synthesized particles were hemispherical–cubic in shape and had an average particle size of less than 100 nm. In addition, the chemical bond structures of the nanoparticles were confirmed in detail by XPS elemental analysis. The highest saturation magnetization was recorded as 33.50 emu/g for the as-produced nanoparticles. The saturation magnetization of the nanoparticles decreased with increasing annealing temperature, while coercivity increased. 相似文献
15.
Hollow mesoporous silica spheres supported Ag and Ag–Au catalyzed reduction of 4-nitrobenzo-15-crown
《Journal of Industrial and Engineering Chemistry》2014,20(3):767-774
Hollow mesoporous silica (HMS) spheres of size within the range 120–220 nm have been prepared using propanol–water solvent as template and cetyltrimethylammonium bromide (CTAB) as stabilizer. HMS supported silver and silver–gold catalysts were prepared by impregnating metal nanoparticles on HMS and were characterized by ultraviolet–visible spectroscopy (UV–vis), dynamic light scattering (DLS), optical microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), inductive coupled plasma optical emission spectroscopy (ICP-OES) and N2 adsorption–desorption. The reduction of 4-nitrobenzo-15-crown (4-NB-15-C) was compared using HMS supported silver and silver–gold nanocatalysts varying experimental parameters. Bimetallic Ag–Au/HMS nanocatalysts was found to be more active than monometallic Ag/HMS nanocatalyst. 相似文献
16.
Ken-Tye Yong Yudhisthira Sahoo Mark T. Swihart Paul M. Schneeberger Paras N. Prasad 《Topics in Catalysis》2008,47(1-2):49-60
Seeded growth of gold nanorods (NRs) has been accomplished in a micellar medium containing mixed surfactants or a high salt
concentration. Cetyl trimethylamoniumbromide (CTAB) forms micelles upon which the growth of rod shaped gold nanoparticles
occurs. AgNO3 is introduced into the growth solution to enhance the formation of NRs. The roles of non-ionic surfactants such as Tween
and Triton, and of electrolytes such as sodium chloride and potassium chloride have been examined. As the concentration of
these additives in the growth solution is increased, the aspect ratio of the NRs increases to a critical limit, after which
it decreases again. Upon carefully controlling the content of Triton X-100 or Tween 20 in the growth solution, these non-ionic
surfactants assisted in fine-tuning the shape of gold NRs (e.g. rectangular or “dogbone”). The growth pattern of the NRs fits
into the model of a soft template formed by the mixture of CTAB and non-ionic surfactants. 相似文献
17.
Reto Strobel Jan-Dierk Grunwaldt Adrian Camenzind Sotiris E. Pratsinis Alfons Baiker 《Catalysis Letters》2005,104(1-2):9-16
Bimetallic palladium–platinum nanoparticles supported on alumina were prepared by flame spray pyrolysis. The as-prepared materials
were characterized by scanning transmission electron microscopy (STEM), CO chemisorption, nitrogen adsorption (BET), X-ray
diffraction (XRD), temperature programmed reduction (TPR), thermogravimetric analysis (TGA) and extended X-ray absorption
fine structure (EXAFS) spectroscopy. The materials were tested for the catalytic combustion of methane with a focus on the
thermal stability of the noble metal particles. After flame synthesis the noble metal components of the materials were predominantly
in oxidized state and finely dispersed on the alumina matrix. Reduction afforded small bimetallic Pd–Pt alloy particles (<
5 nm) supported on Al2O3 ceramic nanoparticles. The addition of small amounts of platinum made the palladium particles more resistant against sintering
at high temperatures and further lowered the deactivation observed during methane combustion. 相似文献
18.
Electrocatalytic effect of nanoporous interface between platinum (Pt) and electrolyte was investigated in terms of direct electrochemical oxidation of glucose. A Pt film with 3D nanopores was electroplated from the hexagonal (H1) lyotropic liquid crystal (LLC) phase of t-octylphenoxypolyethoxyethanol (Triton X-100), a nonionic surfactant with a phenyl group in a hydrophobic tail. This Pt film, which was electroplated from H1-LLC of Triton X-100 (ePt-H1-TX100), comprised closely stacked crystalline (face centered cubic) nanoparticles (diameter, 4-7 nm) with 3D nanopores (width, 1-2 nm) developed among the particles. The ePt-H1-TX100 showed high surface roughness and selective enhancement of a sluggish redox reaction, that is, kinetic-controlled reaction such as glucose oxidation. Nonenzymatic glucose sensing can be achieved by using discriminatively enhanced sensitivity to glucose over redox active interfering molecules. 相似文献
19.
Herein, the generation of gold, silver, and silver–gold (Ag–Au) bimetallic nanoparticles was carried out in collagen (gelatin)
solution. It first showed that the major ingredient in gelatin polypeptide, glutamic acid, acted as reducing agent to biomimetically
synthesize noble metal nanoparticles at 80°C. The size of nanoparticles can be controlled not only by the mass ratio of gelatin
to gold ion but also by pH of gelatin solution. Interaction between noble-metal nanoparticles and polypeptide has been investigated
by TEM, UV–visible, fluorescence spectroscopy, and HNMR. This study testified that the degradation of gelatin protein could
not alter the morphology of nanoparticles, but it made nanoparticles aggregated clusters array (opposing three-dimensional
α-helix folding structure) into isolated nanoparticles stabilized by gelatin residues. This is a promising merit of gelatin
to apply in the synthesis of nanoparticles. Therefore, gelatin protein is an excellent template for biomimetic synthesis of
noble metal/bimetallic nanoparticle growth to form nanometer-sized device. 相似文献
20.
Mesoporous γ-Al2O3 has been successfully synthesized by using calcined coal-series kaolin as raw material and Triton X-100 (TX-100) as template. The effect of TX-100/Al3 + ratio on the structural and textural properties of mesoporous γ-Al2O3 was investigated. Physical properties of obtained samples were characterized by X-ray diffraction (XRD), N2 adsorption–desorption, transmission electron microscopy (TEM), thermogravimetric analysis (TG), scanning electron microscopy (SEM) with energy-dispersive X-ray analysis (EDAX) and Fourier transform infrared spectroscopy (FTIR). The results indicated that the amount of TX-100 influenced the structure and porous properties of mesoporous γ-Al2O3 significantly. When TX-100/Al3 + ratio was in the range of 0.03–0.15, all samples had mesoporous structures with BET surface area of 193.0–261.0 m2/g and pore size of 5.04–6.71 nm. In addition, the reaction mechanism involved in the process was proposed and discussed. 相似文献