共查询到20条相似文献,搜索用时 15 毫秒
1.
Min Wu Yan Lv Zhengping Fu Jiao Xu Ting Guo Yongxun Zhao 《Applied Surface Science》2010,256(23):7125-9486
The simultaneous Ag loaded and N-doped TiO2 hollow nanorod arrays with various contents of silver (Ag/N-THNAs) were successfully synthesized on glass substrates by one-pot liquid phase deposition (LPD) method using ZnO nanorod arrays as template. The catalysts were characterized by Raman spectrum, field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscope (HRTEM), ultraviolet-vis (UV-vis) absorption spectrum and X-ray photoelectron spectroscopy (XPS). The results suggest that AgNO3 additive in the precursor solutions not only can promote the anatase-to-rutile phase transition, but also influence the amount of N doping in the samples. The photocatalytic activity of all the samples was evaluated by photodegradation of methylene blue (MB) in aqueous solution. The sample exhibited the highest photocatalytic activity under UV light illumination when the AgNO3 concentration in the precursor solution was 0.03 M, due to Ag nanoparticles acting as electron sinks; When the AgNO3 concentration was 0.07 M, the sample performed best under visible light illumination, attributed to the synergetic effects of Ag loading, N doping, and the multiphase structure (anatase/rutile). 相似文献
2.
One-step synthesis of silver nanoparticles in an aqueous solution and their antibacterial activities
Guangyu Zhang Feng Zhang Hideaki Morikawa Yueyue Chen 《Applied Physics A: Materials Science & Processing》2014,114(4):1277-1283
A one-step simple synthesis of silver colloid nanoparticles with controllable sizes is presented in this research. In the synthesis, an amino-terminated hyperbranched polymer (HBP-NH2) was applied as a stabilizer and a reductant. The syntheses, performed at various initial AgNO3 concentrations (0.28–0.56 g/l) in a 2 g/l HBP-NH2 aqueous solution, produced silver colloid nanoparticles having average sizes from 3 to 30 nm with narrow size distributions. The formation of silver colloid nanoparticles was characterized by Fourier Transform Infrared Spectrophotometry (FTIR), Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), UV/Visible Absorption Spectrophotometry, and X-ray Diffraction (XRD) measurements. The results indicated that both particle size and the UV absorption are strongly dependent on the initial AgNO3 concentrations. The silver colloid nanoparticles, prepared with a 0.35 g/l AgNO3 aqueous solution in the presences of 2 g/l HBP-NH2, showed good antibacterial activities against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus). A very low concentration of nano-silver (as low as 3.0 ug/ml Ag) also gave excellent antibacterial performance. 相似文献
3.
Nalenthiran Pugazhenthiran Sambandam Anandan Govindarajan Kathiravan Nyayiru Kannaian Udaya Prakash Simon Crawford Muthupandian Ashokkumar 《Journal of nanoparticle research》2009,11(7):1811-1815
A silver resistant Bacillus sp. was isolated through exposure of an aqueous AgNO3 solution to the atmosphere. Silver nanoparticles were synthesized using these airborne bacteria (Bacillus sp.). Transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) analyses confirmed that silver nanoparticles
of 5–15 nm in size were deposited in the periplasmic space of the bacterial cells; a preferable cell surface location for
the easy recovery of biogenic nanoparticles. 相似文献
4.
Ling Huang Maolin L. Zhai Dewu W. Long Jing Peng Ling Xu Guozhong Z. Wu Jiuqiang Q. Li Genshuan S. Wei 《Journal of nanoparticle research》2008,10(7):1193-1202
The silver nanoparticles (AgNPs) were synthesized in an alkalic aqueous solution of silver nitrate (AgNO3)/carboxymethylated chitosan (CMCTS) with ultraviolet (UV) light irradiation. CMCTS, a water-soluble and biocompatible chitosan
derivative, served simultaneously as a reducing agent for silver cation and a stabilizing agent for AgNPs in this method.
UV–vis spectra and transmission electron microscopy (TEM) images analyses showed that the pH of AgNO3/CMCTS aqueous solutions, the concentrations of AgNO3 and CMCTS can affect on the size, amount of synthesized AgNPs. Further by polarized optical microscopy it was found that
the CMCTS with a high molecular weight leads to a branch-like AgNPs/CMCTS composite morphology. The diameter range of the
AgNPs was 2–8 nm and they can be dispersed stably in the alkalic CMCTS solution for more than 6 months. XRD pattern indicated
that the AgNPs has cubic crystal structure. The spectra of laser photolysis of AgNO3/CMCTS aqueous solutions identified the early reduction processes of silver cations (Ag+) by hydrated electron formed by photoionization of CMCTS. The rate constant of corresponding reduction reaction was 5.0 × 109 M−1 s−1. 相似文献
5.
Ying-Kui Yang Cheng-En He Wen-Jie He Lin-Juan Yu Ren-Gui Peng Xiao-Lin Xie Xian-Bao Wang Yiu-Wing Mai 《Journal of nanoparticle research》2011,13(10):5571-5581
Silver nanoparticles (Ag NPs) have been homogeneously deposited onto graphene oxide (GO) nanosheets by an optimal method,
in which N,N-dimethylformamide (DMF) as a co-dispersant of GO and reductant of sliver ions is added to an aqueous suspension of GO and
AgNO3. GO nanosheets are uniformly covered by Ag NPs with a narrow size distribution and inter-particle gap. Raman signals of GO
are greatly enhanced after deposition owing to the charge transfer interaction of GO with Ag NPs. The GO/Ag composite can
be further utilized as an effective surface-enhanced Raman scattering (SERS) active substrate. Several new Raman bands and
frequency shifts are clearly observed in using 4-aminothiophenol (4-ATP) as a Raman probe on GO/Ag compared to the normal
Raman spectrum of solid 4-ATP. The Raman enhancement arises from a major electromagnetic effect and a minor chemical effect. 相似文献
6.
Xiao-Hua Jia Hao-Jie Song Chun-Ying Min 《Applied Physics A: Materials Science & Processing》2013,111(4):1021-1024
A facile hydrothermal method has been developed to be capable of decorating graphene oxide (GO) with flower-like TiO2 nanocrystals without using any bridging species. The flower-like TiO2 nanocrystals were uniformly self-assembled on the surface of GO nanosheets. The photocatalytic activity experiment indicated that the prepared TiO2/GO nanocomposites exhibited a higher photocatalytic activity for the photocatalytic degradation of rhodamine B (RB) aqueous solution under the UV illumination, this methodology made the synthesis of TiO2/GO nanocomposites possible and may be further extended to prepare more complicated nanocomposites based on GO for technological applications. 相似文献
7.
Phyllanthin-assisted biosynthesis of silver and gold nanoparticles: a novel biological approach 总被引:2,自引:0,他引:2
Abstract The anisotropic gold and spherical–quasi-spherical silver nanoparticles (NPs) were synthesized by reducing aqueous chloroauric
acid (HAuCl4) and silver nitrate (AgNO3) solution with the extract of phyllanthin at room temperature. The rate of reduction of HAuCl4 is greater than the AgNO3 at constant amount of phyllanthin extract. The size and shape of the NPs can be controlled by varying the concentration of
phyllanthin extract and thereby to tune their optical properties in the near-infrared region of the electromagnetic spectrum.
The case of low concentration of extract with HAuCl4 offers slow reduction rate along with the aid of electron-donating group containing extract leads to formation of hexagonal-
or triangular-shaped gold NPs. Transmission electron microscopy (TEM) analysis revealed that the shape changes on the gold
NPs from hexagonal to spherical particles with increasing initial concentration of phyllanthin extract. The Fourier transform
infrared spectroscopy and thermogravimetric analyses reveal that the interaction between NPs and phyllanthin extract. The
cyclic voltammograms of silver and gold NPs confirms the conversion of higher oxidation state to zero oxidation state.
Graphical abstract Anisotropic gold and silver nanoparticles were synthesized by a simple procedure using phyllanthin extract as reducing agent.
The rate of bioreduction of AgNO3 is lower than the HAuCl4 at constant concentration of phyllanthin extract. The required size of the nanoparticles can be prepared by varying the concentration
of phyllanthin with AgNO3 and HAuCl4.
相似文献
8.
Ashwani Kumar Singh Mahe Talat D. P. Singh O. N. Srivastava 《Journal of nanoparticle research》2010,12(5):1667-1675
We report a simple and cost effective way for synthesis of metallic nanoparticles (Au and Ag) using natural precursor clove.
Au and Ag nanoparticles have been synthesized by reducing the aqueous solution of AuCl4 and AgNO3 with clove extract. One interesting aspect here is that reduction time is quite small (few minutes instead of hours as compared
to other natural precursors). We synthesized gold and silver nanoparticles of different shape and size by varying the ratio
of AuCl4 and AgNO3 with respect to clove extract, where the dominant component is eugenol. The evolution of Au and Ag nanoparticles from the
reduction of different ratios of AuCl4 and AgNO3 with optimised concentration of the clove extract has been evaluated through monitoring of surface plasmon behaviour as a
function of time. The reduction of AuCl4 and AgNO3 by eugenol is because of the inductive effect of methoxy and allyl groups which are present at ortho and para positions of
proton releasing –OH group as two electrons are released from one molecule of eugenol. This is followed by the formation of
resonating structure of the anionic form of eugenol. The presence of methoxy and allyl groups has been confirmed by FTIR.
To the best of our knowledge, use of clove as reducing agent, the consequent very short time (minutes instead of hours and
without any scavenger) and the elucidation of mechanism of reduction based on FTIR analysis has not been attempted earlier. 相似文献
9.
Highly stable and spherical silver nanoparticles, stabilized by methoxycarbonyl-terminated hyperbranched poly(amine-ester)
(HPAE-COOCH3), were synthesized in water with reducing AgNO3/HPAE-COOCH3 using two methods, viz. NaBH4 and ultraviolet irradiation. HPAE-COOCH3 was found to play a key role in the formation of nanoparticles. UV–visible absorption, Transmission electron microscopic
(TEM), and Fourier transform infrared spectroscopy (FT-IR) had been used to study the structure and characterization of the
silver nanoparticles. The absorption peaks of the silver nanoparticles appear at ~420 nm in UV–visible absorption spectra;
average particle size reduced by NaBH4 is ~30 nm, which is ~10 and ~15 nm, respectively, when ultraviolet irradiation time is 12 and 24 h. FT-IR spectra confirm
that there is strong interaction between silver nanoparticles and HPAE-COOCH3. And silver nanoparticles/HPAE-COOCH3 aqueous solution can keep stable for more than 3 months. 相似文献
10.
《Current Applied Physics》2010,10(6):1442-1447
This paper presents a novel, inexpensive and one-step approach for synthesis of silver nanoparticles (Ag NPs) using arc discharge between titanium electrodes in AgNO3 solution. The resulting nanoparticles were characterized using UV–Vis spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Silver nanoparticles of 18 nm diameter were formed during reduction of AgNO3 in plasma discharge zone. Optical absorption spectroscopy of as prepared samples at 15 A arc current in AgNO3 solution shows a surface plasmon resonance around 410 nm. It was found that sodium citrate acts as a stabilizer and surface capping agent of the colloidal nanoparticles. SEM images exhibit the increase of reduced nanoparticles in 6 min arc duration compared with 1 min arc duration. TEM image of the sample prepared at 6 min arc duration shows narrow size distribution with 18 nm mean particle size. Antibacterial activities of silver nanoparticles were investigated at the presence of Escherichia coli (E-coli) bacteria. 相似文献
11.
《Current Applied Physics》2018,18(9):1026-1033
Reduced graphene oxide/Strontium titanate (RGO/SrTiO3) heterostructured nanocomposite was synthesized by coupling Hummer's synthesized graphene oxide (GO) with hydrothermally synthesized SrTiO3 nanoparticles (SrTiO3) through a facile and unique high energy ultrasonication technique using triple solvents. XRD result confirmed the successful formation of pure, single phase and primitive cubic crystal structure RGO/SrTiO3 heterostructured nanocomposite. SEM result confirmed the successful intercalation of SrTiO3 nanoparticles over the two dimensional networks of RGO nanosheets. The synergistic and beneficial interactions between SrTiO3 and RGO resulted in smaller crystallite size (53 nm), reduced band gap (2.87 eV) and larger specific surface area (31 m2/g) than that of as prepared pure SrTiO3 nanoparticles. RGO strongly influenced the photocatalytic activity of SrTiO3 and hence RGO/SrTiO3 heterostructured nanocomposite exhibited greater efficiency in degrading Rhodamine B (RhB) and Rose Bengal (RB) organic dye pollutants under natural sunlight irradiation than that of pure SrTiO3 nanoparticles. 相似文献
12.
Chen Wang Shiliang Wang Guoping Qian Chuansheng Chen 《Particle & Particle Systems Characterization》2021,38(11):2100177
Nanopowder photocatalyst suffers two serious problems (low photocatalytic efficiency, easy aggregation, and difficult recycling) in water treatment. For solving these issues, a 3D flower-like graphene oxide (GO)/WO3 quantum dots (QDs)/TiO2 microsphere (FWGT) with excellent photocatalytic property is synthesized by a hydrothermal method which can degrade 100% Rhodamine B (RhB) within 10 min under solar light irradiation. Meanwhile, a carbon-fiber cloth/FWGT (CF/FGT) membrane is constructed by decorating the FWGT microsphere on the surface of the carbon-fiber cloth. CF/FGWT membrane displays better photocatalytic activity compared with carbon-fiber cloth/flower-like GO/TiO2 microsphere (CF/FGT) membrane, which the reaction rate constants of CF/FGWT membrane are 3.52 times higher than that of CF/FGT membrane. Moreover, the CF/FGWT membrane shows a little quality loss (about 1.7%) after several recycles, indicating the novel flexible photocatalytic membrane has great potential for purifying water. 相似文献
13.
E. Jimnez Kamal Abderrafi Juan Martínez-Pastor Rafael Abargues Jos Luís Valds Rafael Ibez 《Superlattices and Microstructures》2008,43(5-6):487
Metal nanoparticles can be prepared by a novel technique that consists of the laser ablation of a solid target immersed in a water solution of a metal salt. Silicon was chosen as the most adequate target to synthesize silver and gold nanoparticles from a water solution of either AgNO3 or HAuCl4. The influence of both the silver nitrate concentrations and the irradiation time of the Si target on the optical properties of the Au and Ag nanoparticles have been investigated. The crystalline nature of the metal nanoparticles has been determined by X-ray diffraction (XRD). Average size and particle size distribution have been measured by means of TEM. The absorbance spectra show the characteristic band of the surface resonant plasmon of silver and gold nanoparticles. 相似文献
14.
ZnO nanorods/Fe3O4 nanocomposites as the recyclable photocatalyst were synthesized by a co-precipitation method, with microwave assistant by dropping alkaline solution with Fe3O4 nanoparticles into the aqueous of zinc salt. These Fe3O4 nanoparticles were the nucleated centers for the ZnO nanorods growth so that these nanorods ended with aggregated Fe3O4 nanoparticles. The growth processes and mechanism are explained as those insoluble zinc hydroxides prefer to nucleate on the surface of Fe3O4 nanoparticles (heterogeneous nucleation) rather than nucleated as isolated ZnO nanostructures (homogeneous nucleation). These nanocomposites have strong photocatalytic ability to reduce RhB and moderate magnetization, which make them being good recyclable photocatalysts. 相似文献
15.
Self-assembled silver nanoparticle films at an air-liquid interface and their applications in SERS and electrochemistry 总被引:1,自引:0,他引:1
In this paper, we present a novel technique to prepare silver nanoparticle films by controlling the self-assembly of nanoparticles at an air-liquid interface. In an ethanol-water phase, silver nanoparticles were prepared by reduction of AgNO3 aqueous solution with NaBH4 in the presence of cinnamic acid. It was found that the silver nanoparticles in this process could be trapped at the air-liquid interface to form 2-dimensional nanoparticle films. The morphology of nanoparticle films could be controlled by systematic variation of the experimental parameters. It is worth noting that the nanoparticle films could serve as the active substrates for surface-enhanced Raman scattering (SERS). 4-Aminothiophenol (4-ATP) molecule was used as a test probe to investigate the SERS sensitivity of different nanoparticle films. The results indicated that the nanoparticle films showed excellent Raman enhancement effect. Furthermore, the nanoparticle films prepared by our strategy were found to be efficient electrocatalysts for anodic oxidation of formaldehyde in alkaline medium. 相似文献
16.
Sunghyun Nam Dharnidhar V. Parikh Brian D. Condon Qi Zhao Megumi Yoshioka-Tarver 《Journal of nanoparticle research》2011,13(9):3755-3764
Silver nanoparticles (NPs) were prepared using silver nitrate (AgNO3) as a precursor in an aqueous solution of poly(ethylene glycol) (PEG), which acted as both a reducing and stabilizing agent.
The UV/Vis spectra showed that PEG 100 (100 kg/mol) has a remarkable capability to produce silver NPs at 80 °C, but the production
of silver NPs by both PEG 2 (2 kg/mol) and PEG 35 (35 kg/mol) was negligible. This difference was explained by the conformation
of PEG in the reaction solution: the entangled conformation for PEG 100 and the single-coiled conformation for PEG 2 and PEG
35, which were confirmed by pulse-field-gradient 1H NMR and viscosity measurements. In an aqueous solution, the entangled conformation of PEG 100 facilitated the reduction
reaction by caging silver ions and effectively prevented the agglomeration of formed NPs. The reaction in an aqueous PEG 100
solution was observed to be stable under the conditions of a prolonged reaction time or an increased temperature, while no
reduction reaction occurred in the PEG 2 solution. The synthesis of silver NPs by PEG 100 was well controlled to produce fine
silver NPs with 3.68 ± 1.03 nm in diameter, the size of which remained relatively constant throughout the reaction. 相似文献
17.
TiO2 nanoparticles capped with sodium dodecylbenzenesulfonate (DBS) are synthesized by a sol-hydrothermal process using tetrabutyl titanate and DBS as raw materials. The effects of surface-capping DBS on the surface photovoltage spectroscopy (SPS), photoluminescence (PL) and photocatalytic performance of TiO2 nanoparticles are principally investigated together with their relationships. The results show that the surface of TiO2 nanoparticles can be well capped by DBS groups while the pH value and added DBS amount are controlled at 5.0 and 2% of TiO2 mass weight, respectively, and the linkage between DBS groups and TiO2 surfaces is mainly by means of quasi-sulphonate bond. The intensities of SPS and PL spectra of TiO2 obviously decrease after DBS-capping, while the activity can greatly increase during the photocatalytic degradation of Rhodamine B (RhB) solution, which are mainly attributed to the electron-withdrawing character of the DBS groups. Moreover, the enhancement of photocatalytic activity of DBS-capped TiO2 is also related to the increase in the capability for adsorbing RhB. 相似文献
18.
Graphene oxide based Pt-TiO2 photocatalyst: ultrasound assisted synthesis, characterization and catalytic efficiency 总被引:2,自引:0,他引:2
An ultrasound-assisted method was used for synthesizing nanosized Pt-graphene oxide (GO)-TiO2 photocatalyst. The Pt-GO-TiO2 nanoparticles were characterized by diffused reflectance spectroscopy, X-ray diffraction, N2 BET adsorption-desorption measurements, atomic force microscopy and transmission electron microscopy. The photocatalytic and sonophotocatalytic degradation of a commonly used anionic surfactant, dodecylbenzenesulfonate (DBS), in aqueous solution was carried out using Pt-GO-TiO2 nanoparticles in order to evaluate the photocatalytic efficiency. For comparison purpose, sonolytic degradation of DBS was carried out. The Pt-GO-TiO2 catalyst degraded DBS at a higher rate than P-25 (TiO2), prepared TiO2 or GO-TiO2 photocatalysts. The mineralization of DBS was enhanced by a factor of 3 using Pt-GO-TiO2 compared to the P-25 (TiO2). In the presence of GO, an enhanced rate of DBS oxidation was observed and, when doped with platinum, mineralization of DBS was further enhanced. The Pt-GO-TiO2 catalyst also showed a considerable amount of degradation of DBS under visible light irradiation. The initial solution pH had an effect on the rate of photocatalytic oxidation of DBS, whereas no such effect of initial pH was observed in the sonochemical or sonophotocatalytic oxidation of DBS. The intermediate products formed during the degradation of DBS were monitored using electrospray mass spectrometry. The ability of GO to serve as a solid support to anchor platinum particles on GO-TiO2 is useful in developing new photocatalysts. 相似文献
19.
《Current Applied Physics》2009,9(5):1097-1105
TiO2 nanoparticles doped with different Ag contents were prepared by a modified sol–gel method, using titanium tetraisopropoxide and silver nitrate as precursors and 2-propanol as solvent. Silver was incorporated into the TiO2 matrix via decomposition of AgNO3 during thermal treatment in different atmospheres. Effects of Ag doping on the crystallization and phase transition of the TiO2 nanoparticles were studied using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Raman spectroscopy techniques. While air annealing incorporates silver into TiO2 matrix in silver oxide form, annealing in nitrogen incorporates metallic silver into TiO2. Formation of silver oxide increases the thermal stability of the TiO2 particles. Silver oxide affects the crystallization process of TiO2 particles and the temperature of transition form anatase to rutile. On the other hand, presence of metallic silver in the samples annealed in nitrogen atmosphere decreases the temperature of phase transition of TiO2 nanoparticles. 相似文献
20.
Rati Ranjan Nayak Nilotpala Pradhan Debadhyan Behera Kshyama Madhusikta Pradhan Srabani Mishra Lala Behari Sukla Barada Kanta Mishra 《Journal of nanoparticle research》2011,13(8):3129-3137
An eco-friendly microbial method for synthesis of silver colloid solution with antimicrobial activity is developed using a
fungal strain of Penicillium purpurogenum NPMF. It is observed that increase in concentration of AgNO3 increases the formation of silver nanoparticle. At 5 mM concentration highly populated polydispersed nanoparticles form.
Furthermore, change in pH of the reaction mixture leads to change in shape and size of silver nanoparticles. At lower pH two
peaks are observed in the absorption spectra showing polydispersity of nanoparticles. However, highly monodispersed spherical
nanoparticles of 8–10 nm size form with 1 mM AgNO3 concentration at pH 8. Antimicrobial activity of nanoparticles is demonstrated against pathogenic gram negative bacteria
like Escherichia coli and Pseudomonas aeruginosa, and gram positive bacteria like Staphylococcus aureus. The antimicrobial activity of silver nanoparticles obtained at different initial pH show strong dependence on the surface
area and shape of the nanoparticles. 相似文献