Sonochemically synthesized MnO2 nanoparticles as electrode material for supercapacitors.

Science.gov (United States)

Gnana Sundara Raj, Balasubramaniam; Asiri, Abdullah M; Qusti, Abdullah H; Wu, Jerry J; Anandan, Sambandam

2014-11-01

In this study, manganese oxide (MnO2) nanoparticles were synthesized by sonochemical reduction of KMnO4 using polyethylene glycol (PEG) as a reducing agent as well as structure directing agent under room temperature in short duration of time and characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM), Transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) analysis. A supercapacitor device constructed using the ultrasonically-synthesized MnO2 nanoparticles showed maximum specific capacitance (SC) of 282Fg(-1) in the presence of 1M Ca(NO3)2 as an electrolyte at a current density of 0.5mAcm(-2) in the potential range from 0.0 to 1.0V and about 78% of specific capacitance was retained even after 1000 cycles indicating its high electrochemical stability. Copyright © 2013 Elsevier B.V. All rights reserved.

Nd: YAG laser irradiation effects on structural and magnetic properties of Ni1+xZrxFe2-2xO4 nanoparticles

Science.gov (United States)

Saraf, Tukaram S.; Kounsalye, Jitendra S.; Birajdar, Shankar D.; Shamkuwar, N. R.

2018-05-01

The effect of 112 mJ Nd: YAG laser irradiation on structural, morphological, infrared and magnetic properties of Ni1+xZrxFe2-2xO4 spinel ferrite nanoparticles has been systematically investigated in the present work. The sol-gel auto combustion synthesis method was successfully executed for the synthesis of the present system. All the samples were characterized by X-ray diffraction technique (XRD), scanning electron microscopy (SEM) and infrared spectroscopy (IR) technique. The magnetic properties of the present samples were measured by pulse field hysteresis loop technique. All the properties were measured for laser irradiated samples as well, to understand the effect of irradiation on the properties. The single-phase cubic spinel structure was confirmed by X-ray diffraction patterns of all samples and the disordered structure was observed for irradiated samples. The two principle absorption bands in IR spectra also confirm the formation of the spinel structure. Spherical and agglomerated morphology was observed for Zr4+ substituted nickel ferrite, whereas scratched morphology was observed for the irradiated samples. The grain size confirms the nanocrystalline nature, the crystallite size also evident the same. The magnetic parameters decreased after Zr4+ ion doping and strongly influenced by the irradiation.

Insights into chirality distributions of single-walled carbon nanotubes grown on different CoxMg1-xO solid solutions

DEFF Research Database (Denmark)

He, Maoshuai; Jiang, Hua; Kauppi, Inkeri

2014-01-01

Low-temperature chemical vapor deposition (CVD) growth of single-walled carbon nanotubes (SWNTs) was achieved on two different types of Co xMg1-xO catalysts prepared by different techniques: atomic layer deposition (ALD) and impregnation. The chirality distribution of SWNTs grown on the ALD......-prepared CoxMg1-xO catalyst is wider than that of SWNTs grown on the impregnation-prepared CoxMg 1-xO catalyst. The different chirality distributions of SWNTs are related to their different growth modes. The ALD-prepared CoxMg 1-xO catalyzes the growth of SWNTs by "tip growth" mode, as revealed by in situ...... for the synthesis of SWNTs with high chiral-selectivity. In addition, impregnation-prepared Co xMg1-xO catalysts calcinated at different temperatures were systematically studied and their catalytic performances in synthesizing carbon nanotubes were elucidated. This work illustrates the influence of metal...

Toxicity Study of Silver Nanoparticles Synthesized from Suaeda monoica on Hep-2 Cell Line.

Science.gov (United States)

Satyavani, Kaliyamurthi; Gurudeeban, Selvaraj; Ramanathan, Thiruganasambandam; Balasubramanian, Thangavel

2012-01-01

Recently there has been fabulous excitement in the nano-biotechnological area for the study of nanoparticles synthesis using some natural biological system, which has led the growth advanced nanomaterials. This intention made us to assess the biologically synthesized silver nanoparticles from the leaf of Suaeda monoica (S.monoica) using 1 mM silver nitrate. The leaf extract of S.monoica incubated with 1 mM silver nitrate solution and characterized by UV- spectrometer and AFM. The effect of synthesized silver nanoparticles on Human Epidermoid Larynx Carcinoma cell line was evaluated by the MTT colorimetric technique. As a result we observed gradual change in the colour of extract from greenish to brown. The synthesized silver nanoparticles confirmed by UV at 430 nm and spherical shape identified in the range of 31 nm under AFM. The effect of silver nanoparticles on Human Epidermoid Larynx Carcinoma cell line exhibits a dose-dependent toxicity for the cell tested and the viability of Hep-2 cells decreased to 50 % (IC(50)) at the concentration of 500 nM. Further findings will be determined the exact mechanisms of this cost effective Nano-treatments.

Synthesis, Characterization, and Gas-Sensing Properties of Mesoporous Nanocrystalline Sn(x)Ti(1-x)O2.

Science.gov (United States)

Zhong, Cheng; Lin, Zhidong; Guo, Fei; Wang, Xuehua

2015-06-01

A nanocomposite mesoporous material composed by SnO2 and TiO2 with the size of -5-9 nm were prepared via a facile wet-chemical approach combining with an annealing process. The microstructure of obtained Sn(x)Ti(1-x)O2 powders were characterized by X-ray diffraction, X-ray Photo-electronic Spectroscopy, scanning electron microscope, transmission electron microscope and nitrogen adsorption-desorption experiment. The gas sensing performances to several gases of the mesoporous material were studied. The sensors of Sn(x)Ti(1-x)O2 (ST10, with 9.1% Ti) exhibited very high responses to volatile organic compounds at 160 degrees C. The order of the responses to volatile gases based on ST10 was ethanol > formaldehyde > acetone > toluene > benzene > methane. Sensor based on ST10 displays a highest sensitivity to hydrogen at 200 degrees C. Sensor responses to H2 at 200 degrees C have been measured and analyzed in a wide concentration range from 5 to 2000 ppm. The solid solution Sn(x)Ti(1-x)O2 can be served as a potential gas-sensing material for a broad range of future sensor applications.

Study of photocatalytic activities of Bi2WO6 nanoparticles synthesized by fast microwave-assisted method

International Nuclear Information System (INIS)

Phu, Nguyen Dang; Hoang, Luc Huy; Chen, Xiang-Bai; Kong, Meng-Hong; Wen, Hua-Chiang; Chou, Wu Ching

2015-01-01

We present a study of photocatalytic activities of Bi 2 WO 6 nanoparticles synthesized by fast microwave-assisted method. The photocatalytic activities of the nanoparticles were evaluated by the decolorization of methylene-blue under visible-light-irradiation. Our results show that the surface area of Bi 2 WO 6 nanoparticles plays a major role for improving photocatalytic activity, while visible-light absorption has only a weak effect on photocatalytic activity. This suggests efficient transportation of photo-generated electrons and holes to the oxidation active sites on the surface of nanoparticles, indicating Bi 2 WO 6 nanoparticles synthesized by fast microwave-assisted method are promising for achieving high photocatalytic activity under visible-light-irradiation. - Highlights: • The Bi 2 WO 6 nanoparticles were synthesized via fast microwave-assisted method. • The obtained Bi 2 WO 6 nanoparticles exhibited visible-light absorbance. • The surface area of Bi 2 WO 6 nanoparticles plays major role for improving photocatalytic activity. • The Bi 2 WO 6 nanoparticles are promising for achieving high photocatalytic activity under visible-light-irradiation

Role of additives; sodium dodecyl sulphate and manganese chloride on morphology of Zn{sub 1−x}Mn{sub x}O nanoparticles and their photoluminescence properties

Energy Technology Data Exchange (ETDEWEB)

Pandey, Gajanan, E-mail: pandeygajanan@rediffmail.com [Department of Applied Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, U.P. (India); Dixit, Supriya; Shrivastava, A.K. [School of Studies in Physics, Jiwaji University, Gwalior 474011, M.P. (India)

2014-10-15

In the present study Zn{sub 1−x}Mn{sub x}O (x = 0, 0.05 and 0.1) nanoparticles (NPs) have been synthesised in aqueous solution phase at mild reaction temperature 100 °C in moderate alkaline medium (pH = 9.5), and the role of external additives; like sodium dodecyl sulphate and manganese chloride on the morphology and size of the products has been explored on the basis of transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectral analyses data. ZnO hexagonal nano-plates, core–shell like spherical/ellipsoidal Zn{sub 0.95}Mn{sub 0.05}O structures and thin sheets, thorn/needle mixed shaped Zn{sub 0.9}Mn{sub 0.1}O structures have been observed in TEM and SEM images. Zn(OH){sub 2} formed in moderate alkaline medium, converted to Zn(II) hydroxo complex ions on dissolution, which further recrystallizes to produce wurtzite ZnO at 100 °C. From XRD and EDX analysis, successful doping of Mn{sup 2+} ions at the Zn{sup 2+} sites in ZnO host has been proved. In the photoluminescence spectra, the observed blue shifts in NBE peaks and decrease of emissions intensity on Mn doping have thoroughly been discussed in the present investigation. - Highlights: • Zn{sub 1−x}Mn{sub x}O NPs have been prepared in aqueous solution at mild temperature 100 °C. • Shifts in XRD lines and NBE peaks in PL spectra proved doping of Mn{sup 2+} in the ZnO. • ZnO is formed via dissolution–recrystallization of ε-Zn(OH){sub 2}–ZnO. • Additives SDS and MnCl{sub 2}·4H{sub 2}O play important role on morphology of Zn{sub 1−x}Mn{sub x}O NPs. • Mn contents increased extrinsic defects, which decreased intensity of PL spectra.

NiCrxFe2− xO4 ferrite nanoparticles and their composites with ...

Indian Academy of Sciences (India)

Half of the samples have been sintered at 620°C and the other at 1175°C. Then polypyrrole (PPy)–NiCrFe2-O4 composites have been synthesized by polymerization of pyrrole monomer in the presence of NiCrFe2-O4 nanoparticles. The structure, morphology and magnetic properties of the samples have been ...

Indium doped Cd{sub 1-x}Zn{sub x}O alloys as wide window transparent conductors

Energy Technology Data Exchange (ETDEWEB)

Zhu, Wei [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Physics, The Center for Physical Experiments, University of Science and Technology of China, Hefei, Anhui 230026 (China); Yu, Kin Man, E-mail: kinmanyu@cityu.edu.hk [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Physics and Materials Science, City University of Hong Kong, Kowloon (Hong Kong); Walukiewicz, W. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2015-12-31

We have synthesized Indium doped Cd{sub 1-x}Zn{sub x}O alloys across the full composition range using magnetron sputtering method. The crystallographic structure of these alloys changes from rocksalt (RS) to wurtzite (WZ) when the Zn content is higher than 30%. The rocksalt phase alloys in the composition range 0 < x < 0.3 can be efficiently n-type doped, shifting the absorption edge to 3.25 eV and reducing resistivity to about 2.0 × 10{sup −4} Ω-cm. We found that In doped CdO (ICO) transmits more solar photons than commercial fluorine doped tin oxide (FTO) with comparable sheet conductivity. The infrared transmittance is further extended to longer than 1500 nm wavelengths by depositing the In doped Cd{sub 1-x}Zn{sub x}O in ~ 1% of O{sub 2}. This material has a potential for applications as a transparent conductor for silicon and multi-junction solar cells. - Highlights: • Indium doped Cd1-xZnxO alloys across the full composition range were synthesized. • Alloys change from rocksalt (RS) to wurtzite (WZ) when x is higher than 30%. • RS-Cd1-xZnxO phase can be doped with In as efficiently as CdO, achieving a low resistivity ~ 2.0 × 10{sup −4} Ω-cm. • Wide transparency window from 380 to 1200 nm • In doped CdO transmits more solar photons than commercial fluorine doped tin oxide.

Effect of Co substitution on absorption properties of SrCoxFe12-xO19 hexagonal ferrites based nanocomposites in X-band

Science.gov (United States)

Chakraborty, Soma; Bhattacharyya, Nidhi Saxena; Bhattacharyya, Satyajib

2017-12-01

Cobalt doped M-type strontium hexaferrite nanoparticles (SrCoxFe12-xO19, x = 0.2-1.2) is synthesized and used as inclusions in Linear Low Density Polyethylene (LLDPE) matrix for developing nano-composites with 60 wt% of these nanoparticles. Absorption performance of the developed nano-composites is evaluated in the X-band. The thickness optimization is carried out for obtaining maximum reflection loss by using the transmission line model (TLM), with measured values of permittivity and permeability of the composite. The best reflection loss is observed experimentally for x = 0.8 with an absorber thickness of 3 mm for which a wide -10 dB bandwidth covering almost the entire X-band is obtained. The composites are light weight and not affected by exposure to water.

Evaluation of Biological Activities of Chemically Synthesized Silver Nanoparticles

International Nuclear Information System (INIS)

Mostafa, A. A.; Solkamy, E.N.; Sayed, Sh. R. M.; Khan, M.; Shaik, M.R.; Al-Warthan, A.; Adil, S.F.

2015-01-01

Silver nanoparticles were synthesized by the earlier reported methods. The synthesized nanoparticles were characterized using ultraviolet-visible spectrophotometry (UV/Vis), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and X-ray powder diffraction (XRD). The synthesized materials were also evaluated for their antibacterial activity against Gram positive and Gram negative bacterial strains. TEM micrograph showed the spherical morphology of AgNPs with size range of 40-60 nm. The synthesized nanoparticles showed a strong antimicrobial activity and their effect depends upon bacterial strain as AgNPs exhibited greater inhibition zone for Pseudomonas aeruginosa (19.1 mm) followed by Staphylococcus aureus (14.8?mm) and S. pyogenes (13.6 mm) while the least activity was observed for Salmonella typhi (12.5 mm) at concentration of 5 μg/disc. The minimum inhibitory concentration (MIC) of AgNPs against S. aureus was 2.5 μg/disc and less than 2.5 μg/disc for P. aeruginosa. These results suggested that AgNPs can be used as an effective antiseptic agent for infectious control in medical field.

Biogenic synthesized nanoparticles and their applications

Energy Technology Data Exchange (ETDEWEB)

Singh, Abhijeet, E-mail: abhijeet.singh@jaipur.manipal.edu; Sharma, Madan Mohan [Manipal University Jaipur (India)

2016-05-06

In the present scenario, there are growing concerns over the potential impacts of bioengineered nanoparticles in the health sector. However, our understanding of how bioengineered nanoparticles may affect organisms within natural ecosystems, lags far behind our rapidly increasing ability to engineer novel nanoparticles. To date, research on the biological impacts of bioengineered nanoparticles has primarily consisted of controlled lab studies of model organisms with single species in culture media. Here, we described a cost effective and environment friendly technique for green synthesis of silver nanoparticles. Silver nanoparticles were successfully synthesized from 1 mM AgNO{sub 3} via a green synthesis process using leaf extract as reducing as well as capping agent. Nanoparticles were characterized with the help of UV–vis absorption spectroscopy, X-ray diffraction and TEM analysis which revealed the size of nanoparticles of 30-40 nm size. Further the nanoparticles synthesized by green route are found highly toxic against pathogenic bacteria and plant pathogenic fungi viz. Escherichia coli, Pseudomonas syringae and Sclerotiniasclerotiorum. The most important outcome of this work will be the development of value-added products and protection of human health from pathogens viz., bacteria, virus, fungi etc.

Biogenic synthesized nanoparticles and their applications

International Nuclear Information System (INIS)

Singh, Abhijeet; Sharma, Madan Mohan

2016-01-01

In the present scenario, there are growing concerns over the potential impacts of bioengineered nanoparticles in the health sector. However, our understanding of how bioengineered nanoparticles may affect organisms within natural ecosystems, lags far behind our rapidly increasing ability to engineer novel nanoparticles. To date, research on the biological impacts of bioengineered nanoparticles has primarily consisted of controlled lab studies of model organisms with single species in culture media. Here, we described a cost effective and environment friendly technique for green synthesis of silver nanoparticles. Silver nanoparticles were successfully synthesized from 1 mM AgNO_3 via a green synthesis process using leaf extract as reducing as well as capping agent. Nanoparticles were characterized with the help of UV–vis absorption spectroscopy, X-ray diffraction and TEM analysis which revealed the size of nanoparticles of 30-40 nm size. Further the nanoparticles synthesized by green route are found highly toxic against pathogenic bacteria and plant pathogenic fungi viz. Escherichia coli, Pseudomonas syringae and Sclerotiniasclerotiorum. The most important outcome of this work will be the development of value-added products and protection of human health from pathogens viz., bacteria, virus, fungi etc.

Study of photocatalytic activities of Bi{sub 2}WO{sub 6} nanoparticles synthesized by fast microwave-assisted method

Energy Technology Data Exchange (ETDEWEB)

Phu, Nguyen Dang [Faculty of Physics, Hanoi National University of Education, 136 Xuanthuy, Cau Giay, Hanoi (Viet Nam); Hoang, Luc Huy, E-mail: hoanglhsp@hnue.edu.vn [Faculty of Physics, Hanoi National University of Education, 136 Xuanthuy, Cau Giay, Hanoi (Viet Nam); Chen, Xiang-Bai, E-mail: xchen@wit.edu.cn [School of Science and Laboratory of Optical Information Technology, Wuhan Institute of Technology, Wuhan 430205 (China); Kong, Meng-Hong [School of Science and Laboratory of Optical Information Technology, Wuhan Institute of Technology, Wuhan 430205 (China); Wen, Hua-Chiang; Chou, Wu Ching [Department of Electrophysics, National Chiao Tung University, Hsin-Chu 30010, Taiwan (China)

2015-10-25

We present a study of photocatalytic activities of Bi{sub 2}WO{sub 6} nanoparticles synthesized by fast microwave-assisted method. The photocatalytic activities of the nanoparticles were evaluated by the decolorization of methylene-blue under visible-light-irradiation. Our results show that the surface area of Bi{sub 2}WO{sub 6} nanoparticles plays a major role for improving photocatalytic activity, while visible-light absorption has only a weak effect on photocatalytic activity. This suggests efficient transportation of photo-generated electrons and holes to the oxidation active sites on the surface of nanoparticles, indicating Bi{sub 2}WO{sub 6} nanoparticles synthesized by fast microwave-assisted method are promising for achieving high photocatalytic activity under visible-light-irradiation. - Highlights: • The Bi{sub 2}WO{sub 6} nanoparticles were synthesized via fast microwave-assisted method. • The obtained Bi{sub 2}WO{sub 6} nanoparticles exhibited visible-light absorbance. • The surface area of Bi{sub 2}WO{sub 6} nanoparticles plays major role for improving photocatalytic activity. • The Bi{sub 2}WO{sub 6} nanoparticles are promising for achieving high photocatalytic activity under visible-light-irradiation.

Effects of processing parameters on the morphology, structure, and magnetic properties of Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles synthesized with chemical methods

Energy Technology Data Exchange (ETDEWEB)

Ivantsov, R.D. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Edelman, I.S., E-mail: ise@iph.krasn.ru [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Zharkov, S.M.; Velikanov, D.A. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Petrov, D.A. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Ovchinnikov, S.G. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036 (Russian Federation); Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Lin, Chun-Rong [National Pingtung University, Pingtung City, Pingtung County, 90003, Taiwan (China); Li, Oksana [Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); National Pingtung University, Pingtung City, Pingtung County, 90003, Taiwan (China); Tseng, Yaw-Teng [National Pingtung University, Pingtung City, Pingtung County, 90003, Taiwan (China)

2015-11-25

Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles with x = 0, 0.2, and 0.4 were synthesized via thermal decomposition of metal nitrate or chloride salts and selenium powder using different precursor compositions and processing details. Single crystalline nano-belts or nano-rods coexist in the synthesized powder samples with hexagon-shaped plates in dependence on the precursor composition. The belts gathered into conglomerates forming “hierarchical” particles. Visible magnetic circular dichroism (MCD) of Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles embedded into a transparent matrix was investigated for the first time. The similarity of the MCD spectra of all samples showed the similarity of the nanoparticles electronic structure independent of their morphology. Basing on the MCD spectral maxima characteristics, electron transitions from the ground to the excited states were identified with the help of the conventional band theory and the multi-electron approach. - Highlights: • Single crystalline Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles with x = 0, 0.2, 0.4 were synthesized. • Correlation between synthesis conditions and nanoparticles morphology were obtained. • The nanoparticles magnetization behavior was studied. • Visible MCD of the Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles were studied for the first time.

APOSTLE: LONGTERM TRANSIT MONITORING AND STABILITY ANALYSIS OF XO-2b

Energy Technology Data Exchange (ETDEWEB)

Kundurthy, P.; Barnes, R.; Becker, A. C.; Agol, E.; Williams, B. F.; Rose, A. [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Gorelick, N. [Google Inc., Mountain View, CA 94043 (United States)

2013-06-10

The Apache Point Survey of Transit Lightcurves of Exoplanets (APOSTLE) observed 10 transits of XO-2b over a period of 3 yr. We present measurements that confirm previous estimates of system parameters like the normalized semi-major axis (a/R{sub *}), stellar density ({rho}{sub *}), impact parameter (b), and orbital inclination (i{sub orb}). Our errors on system parameters like a/R{sub *} and {rho}{sub *} have improved by {approx}40% compared to previous best ground-based measurements. Our study of the transit times show no evidence for transit timing variations (TTVs) and we are able to rule out co-planar companions with masses {>=}0.20 M{sub Circled-Plus} in low order mean motion resonance with XO-2b. We also explored the stability of the XO-2 system given various orbital configurations of a hypothetical planet near the 2:1 mean motion resonance. We find that a wide range of orbits (including Earth-mass perturbers) are both dynamically stable and produce observable TTVs. We find that up to 51% of our stable simulations show TTVs that are smaller than the typical transit timing errors ({approx}20 s) measured for XO-2b, and hence remain undetectable.

Synthesis and Electrochemical Performance of Graphene Wrapped SnxTi1−xO2 Nanoparticles as an Anode Material for Li-Ion Batteries

Directory of Open Access Journals (Sweden)

Xing Xin

2015-01-01

Full Text Available Ever-growing development of Li-ion battery has urged the exploitation of new materials as electrodes. Here, SnxTi1-xO2 solid-solution nanomaterials were prepared by aqueous solution method. The morphology, structures, and electrochemical performance of SnxTi1-xO2 nanoparticles were systematically investigated. The results indicate that Ti atom can replace the Sn atom to enter the lattice of SnO2 to form substitutional solid-solution compounds. The capacity of the solid solution decreases while the stability is improved with the increasing of the Ti content. Solid solution with x of 0.7 exhibits the optimal electrochemical performance. The Sn0.7Ti0.3O2 was further modified by highly conductive graphene to enhance its relatively low electrical conductivity. The Sn0.7Ti0.3O2/graphene composite exhibits much improved rate performance, indicating that the SnxTi1-xO2 solid solution can be used as a potential anode material for Li-ion batteries.

Structural and electrical properties of TiO2/ZnO core–shell nanoparticles synthesized by hydrothermal method

International Nuclear Information System (INIS)

Vlazan, P.; Ursu, D.H.; Irina-Moisescu, C.; Miron, I.; Sfirloaga, P.; Rusu, E.

2015-01-01

TiO 2 /ZnO core–shell nanoparticles were successfully synthesized by hydrothermal method in two stages: first stage is the hydrothermal synthesis of ZnO nanoparticles and second stage the obtained ZnO nanoparticles are encapsulated in TiO 2 . The obtained ZnO, TiO 2 and TiO 2 /ZnO core–shell nanoparticles were investigated by means of X-ray diffraction, transmission electron microscopy, Brunauer, Emmett, Teller and resistance measurements. X-ray diffraction analysis revealed the presence of both, TiO 2 and ZnO phases in TiO 2 /ZnO core–shell nanoparticles. According to transmission electron microscopy images, ZnO nanoparticles have hexagonal shapes, TiO 2 nanoparticles have a spherical shape, and TiO 2 /ZnO core–shell nanoparticles present agglomerates and the shape of particles is not well defined. The activation energy of TiO 2 /ZnO core–shell nanoparticles was about 101 meV. - Graphical abstract: Display Omitted - Highlights: • TiO 2 /ZnO core–shell nanoparticles were synthesized by hydrothermal method. • TiO 2 /ZnO core–shell nanoparticles were investigated by means of XRD, TEM and BET. • Electrical properties of TiO 2 /ZnO core–shell nanoparticles were investigated. • The activation energy of TiO 2 /ZnO core–shell nanoparticles was about E a = 101 meV

Electrophoretic deposition of Cu2ZnSn(S0.5Se0.5)4 films using solvothermal synthesized nanoparticles

Science.gov (United States)

Badkoobehhezaveh, Amir Masoud; Abdizadeh, Hossein; Golobostanfard, Mohammad Reza

2018-01-01

In this paper, a simple, practical, and fast solvothermal route is presented for synthesizing the Cu2ZnSn(S0.5Se0.5)4 nanoparticles (CZTSSe). In this method, the precursors were dissolved in triethylenetetramine and placed in an autoclave at 240 °C for 1 h under controlled pressure and constant stirring. After washing the samples for several times with absolute ethanol, the obtained CZTSSe nanoparticles were successfully deposited on fluorine doped tin oxide substrates by convenient electrophoretic deposition (EPD) using colloidal nanoparticles. The most appropriate parameters for EPD of pre-synthesized CZTSSe nanoparticles which result in proper surface properties, controlled thickness, and high film quality are investigated by adjusting applied voltage, pH, and deposition time. X-ray diffraction pattern and Raman spectroscopy of the pre-synthesized nanoparticles show kesterite structure formation. The particle size of the CZTSSe nanoparticles is in the range of 100 to 400 nm and for some agglomerates, it is about 2 µm confirmed by scanning electron microscope. The deposited film with optimized parameter has acceptable quality without any crack in it with the thickness of about 4-5 µm. Energy-dispersive X-ray spectroscopy confirms that the chemical composition of the samples is in near stoichiometric Cu-poor and Zn-rich region, which guarantees the p-type character of the film. The diffuse reflectance spectroscopy also demonstrates that the optical band gap of the sample is about 1.2 eV.

Structural and morphological properties of HfxZr 1-xO2 thin films prepared by Pechini route

KAUST Repository

García-Cerda, L. A.

2010-03-01

In this study, HfxZr1-xO2 (0 < x < 1) thin films were deposited on silicon wafers using a dip-coating technique and by using a precursor solution prepared by the Pechini route. The effects of annealing temperature on the structure and morphological properties of the proposed films were investigated. HfxZr1-xO2 thin films with 1, 3 and 5 layers were annealed in air for 2 h at 600 and 800 °C and the structural and morphological properties studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results show that the films have monoclinic and tetragonal structure depending of the Hf and Zr concentration. SEM photographs show that all films consist of nanocrystalline grains with sizes in the range of 6 - 13 nm. The total film thickness is about 90 nm. © (2010) Trans Tech Publications.

Synthesis and Electrochemical Properties of Ni Doped Spinel LiNixMn2-xO4 (0 ≤ x ≤ 0.5) Cathode Materials for Li-Ion Battery

CSIR Research Space (South Africa)

Kebede, M

2013-11-01

Full Text Available Spherical pristine LiMn2O4 and Ni doped LiNixMn2-xO4 (x=0.1, 0.2, 0.3, 0.4, 0.5) cathode materials for lithium ion battery with high first cycle discharge capacity and excellent cycle performance were synthesized using the solution...

Structure and electrochemical impedance of LiNi_xMn_2_-_xO_4

International Nuclear Information System (INIS)

Ta Anh Tan; Nguyen Si Hieu; Le Ha Chi; Pham Duy Long; Dang Tran Chien; Le Dinh Trong

2016-01-01

Ni-substitution spinel LiNi_xMn_2_-_xO_4 (x = 0, 0.1, 0.2) materials were synthesized by the sol--gel method. The structure and morphology of the samples were characterized by the X-ray diffraction (XRD) and the scanning electron microscopy. The ac conduction of the materials was investigated by electrochemical impedance spectroscopy (EIS) measurements. The refinement results showed that the substitution of Ni decreased the lattice constant and Mn--O distance, while increased Li--O bond length and 16c octahedral volume. The EIS results confirmed the decrease of conductivity with increasing Ni substitution content. Based on XRD and EIS results, the relationship between the crystal structure and electrochemical behavior of the materials was discussed and explained. (author)

Magnetic and photocatalytic studies on Zn1-xMgxFe2O4 nanocolloids synthesized by solvothermal reflux method.

Science.gov (United States)

Manohar, A; Krishnamoorthi, C

2017-12-01

Biocompatible magnetic semiconductor Zn 1-x Mg x Fe 2 O 4 (x=0, 0.1, 0.3, 0.5 & 0.7) nanoparticles of around 10nm diameter were synthesized by solvothermal reflux method. The method produces well separated and narrow size distributed nanoparticles. Crystal structure, morphology, particles surface properties, surfactant quantity, colloidal stability, magnetic properties and photocatalytic properties of the synthesized nanoparticles were studied. Different characterizations confirmed that all compounds were single crystals and superparamagnetic at room temperature. Saturation mass magnetization (M s =57.5emu/g) enhances with substituent Mg 2+ concentration due to promotion of mixed spinel (normal and inverse) structure. Photocatalytic activity of all synthesized magnetic semiconductor nanoparticles were studied through methylene blue degradation. The degradation of 98% methylene blue was observed on 60 min irradiation of light. It is observed that photocatalytic activity slightly enhances with substituent Mg 2+ concentration. The synthesized biocompatible magnetic semiconductor nanoparticles can be utilized as photocatalysts and could also be recycled and separated by applying an external magnetic field. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of precursor on the morphology and size of ZrO2 nanoparticles, synthesized by sol-gel method in non-aqueous medium

International Nuclear Information System (INIS)

Siddiqui, Mohammed Rafiq Hussain; Al-Wassil, Abdulaziz Ibrahim; Mahfouz, Refaat Mohamad; Al-Otaibi, Abdullah Mohmmed

2012-01-01

Pure zirconium oxide (ZrO 2 ) nanoparticles with diameters 10-25 nm were synthesized from ZrOCl 2 .8H 2 O and Zr(SO 4 )2.H 2 O with benzyl alcohol as non-aqueous solvent medium using sol-gel method. Sodium lauryl sulfate was added as surfactants to control the particle size. The synthesized ZrO 2 nanoparticles have a mixture of tetragonal and monoclinic structure. The XRD showed the purity of obtained ZrO 2 nanoparticles with tetragonal and monoclinic phase and the crystallite size for ZrOCl 2 .8H 2 O precursor was estimated to be 18.1 nm and that from Zr(SO 4 )2.H 2 O was 9.7 nm. The transmission electron microscopy and scanning electron microscopic studies also shows different sizes of nanoparticles and different morphology depending on the precursor used for the synthesis of ZrO 2 nanoparticles. (author)

Structural and morphological properties of HfxZr 1-xO2 thin films prepared by Pechini route

KAUST Repository

Garcí a-Cerda, L. A.; Puente-Urbina, B. A.; Quevedo-Ló pez, Manuel Angel Quevedo; Gnade, Bruce E.; Baldenegro-Pé rez, Leonardo Aurelio; Alshareef, Husam N.; Herná ndez-Landaverde, Martí n Adelaido

2010-01-01

In this study, HfxZr1-xO2 (0 < x < 1) thin films were deposited on silicon wafers using a dip-coating technique and by using a precursor solution prepared by the Pechini route. The effects of annealing temperature on the structure and morphological

Effects of precursor on the morphology and size of ZrO2 nanoparticles, synthesized by sol-gel method in non-aqueous medium

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Mohammed Rafiq Hussain Siddiqui

2012-12-01

Full Text Available Pure zirconium oxide (ZrO2 nanoparticles with diameters 10-25 nm were synthesized from ZrOCl2.8H2O and Zr(SO42.H2O with benzyl alcohol as non-aqueous solvent medium using sol-gel method. Sodium lauryl sulfate was added as surfactants to control the particle size. The synthesized ZrO2 nanoparticles have a mixture of tetragonal and monoclinic structure. The XRD showed the purity of obtained ZrO2 nanoparticles with tetragonal and monoclinic phase and the crystallite size for ZrOCl2.8H2O precursor was estimated to be 18.1 nm and that from Zr(SO42.H2O was 9.7 nm. The transmission electron microscopy and scanning electron microscopic studies also shows different sizes of nanoparticles and different morphology depending on the precursor used for the synthesis of ZrO2 nanoparticles

Effect of zinc oxide nanoparticles synthesized by a precipitation

Indian Academy of Sciences (India)

ZnO nanoparticles were synthesized by a precipitation method in aqueous media from zinc nitrate hexahydrate and sodium hydroxide. The synthesized ZnO nanoparticles exhibited a crystalline structure with hexagonal structure of the wurtzite. The morphology of the synthesized ZnO nanoparticles presented a spherical ...

Cytotoxic Effect on Cancerous Cell Lines by Biologically Synthesized Silver Nanoparticles

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Balaji Kulandaivelu

Full Text Available The biosynthesis of nanoparticles has been proposed as an environmental friendly and cost effective alternative to chemical and physical methods. Silver nanoparticles are biologically synthesized and characterized were used in the study. The invitro cytotoxic effect of biologically synthesized silver nanoparticles against MCF-7 cancer cell lines were assessed. The cytotoxic effects of the silver nanoparticles could significantly inhibited MCF-7 cancer cell lines proliferation in a time and concentration-dependent manner by MTT assay. Acridine orange, ethidium bromide (AO/EB dual staining, caspase-3 and DNA fragmentation assays were carried out using various concentrations of silver nanoparticles ranging from 1 to 100 μg/mL. At 100 μg/mL concentration, the silver nanoparticles exhibited significant cytotoxic effects and the apoptotic features were confirmed through caspase-3 activation and DNA fragmentation assays. Western blot analysis has revealed that nanoparticle was able to induce cytochrome c release from the mitochondria, which was initiated by the inhibition of Bcl-2 and activation of Bax. Thus, the results of the present study indicate that biologically synthesized silver nanoparticles might be used to treat breast cancer. The present studies suggest that these nanoparticles could be a new potential adjuvant chemotherapeutic and chemo preventive agent against cytotoxic cells. However, it necessitates clinical studies to ascertain their potential as anticancer agents.

Electrokinetic properties of PMAA functionalized NiFe2O4 nanoparticles synthesized by thermal plasma route

Science.gov (United States)

Bhosale, Shivaji V.; Mhaske, Pravin; Kanhe, N.; Navale, A. B.; Bhoraskar, S. V.; Mathe, V. L.; Bhatt, S. K.

2014-04-01

The magnetic nickel ferrite (NiFe2O4) nanoparticles with an average size of 30nm were synthesised by Transferred arc DC Thermal Plasma route. The synthesized nickel ferrite nanoparticles were characterized by TEM and FTIR techniques. The synthesized nickel ferrite nanoparticles were further functionalized with PMAA (polymethacrylic acid) by self emulsion polymerization method and subsequently were characterized by FTIR and Zeta Analyzer. The variation of zeta potential with pH was systematically studied for both PMAA functionalized (PNFO) and uncoated nickel ferrite nanoparticles (NFO). The IEP (isoelectric points) for PNFO and NFO was determined from the graph of zeta potential vs pH. It was observed that the IEP for NFO was at 7.20 and for PNFO it was 2.52. The decrease in IEP of PNFO was attributed to the COOH functional group of PMAA.

Synthesis of single phase chalcopyrite CuIn1−xGaxSe2 (0 ≤ x ≤ 1) nanoparticles by one-pot method

International Nuclear Information System (INIS)

Han, Zhaoxia; Zhang, Dawei; Chen, Qinmiao; Hong, Ruijin; Tao, Chunxian; Huang, Yuanshen; Ni, Zhengji; Zhuang, Songlin

2014-01-01

Graphical abstract: - Highlights: • A facile and rapid one-pot synthesis method is presented. • The effects of various Ga contents are investigated. • Single phase chalcopyrite CuIn 1−x Ga x Se 2 nanoparticles can be easily synthesized. • The phase formation sequence is from CuSe to CuGaSe 2 , then to CuIn 1−x Ga x Se 2 . • The possible reaction mechanism of CuIn 1−x Ga x Se 2 nanoparticles is proposed. - Abstract: Single phase chalcopyrite and near stoichiometric CuIn 1−x Ga x Se 2 (0 ≤ x ≤ 1) nanoparticles were successfully synthesized by using a facile and rapid one-pot method. The effects of various Ga contents on crystal phase, morphology, element composition and absorption spectrum of the as-synthesized CuIn 1−x Ga x Se 2 nanoparticles were investigated in detail. The XRD and Raman patterns indicated that the as-synthesized nanoparticles had a single phase chalcopyrite structure, and the diffraction peaks shifted toward larger diffraction angles or higher frequencies with increasing Ga content. The FE-SEM images showed that the as-synthesized nanoparticles were polydispersed in both size and shape, and the nanoparticles with higher Ga content were more prone to aggregate. The Vis–IR absorption spectra showed strong absorption in the entire visible light region. The estimated band gap increased from 1.00 eV to 1.68 eV as Ga content increasing

Phase relations, crystal structure, and phase transformation of In_1_−_xNb_1_−_xTi_2_xO_4 (0 ≤ x < 0.45) in In_2O_3–Nb_2O_5–TiO_2 system

International Nuclear Information System (INIS)

Su, Liumei; Fan, Xing; Cai, Gemei; Liu, Huashan; Jin, Zhanpeng

2015-01-01

Phase relations, crystal structures, and phase transformation of In_1_−_xNb_1_−_xTi_2_xO_4 (0 ≤ x < 0.45) in In_2O_3–Nb_2O_5–TiO_2 ternary system were investigated for the first time. A number of samples with different compositions were prepared by a solid-state reaction method, and phase assembles were analyzed by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe micro-analysis (EPMA). Five three-phase regions, ten two-phase regions, and six single-phase solid solutions were determined in this system. The solid solution of In_1_−_xNb_1_−_xTi_2_xO_4 (0 ≤ x < 0.45) is composed of both ordered monoclinic wolframite-type structure (0 ≤ x < 0.35) and disordered orthorhombic α-PbO_2 type structure (0.35 < x < 0.45). Driving force for composition-driven phase transformation in In_1_−_xNb_1_−_xTi_2_xO_4 (0 ≤ x < 0.45) stems from the ordering of cations. The ever reported compound InNbTiO_6 with an orthorhombic α-PbO_2 type structure was amended to be a monoclinic wolframite-type structure. Present investigations will be useful for the whole ceramic community working with In_2O_3–Nb_2O_5–TiO_2 ternary system as well as for the development of functional materials. - Highlights: • Phase relations of In_2O_3–Nb_2O_5–TiO_2 ternary system were constructed. • Crystal structures of a novel solid solution In_1_−_xNb_1_−_xTi_2_xO_4 were determined. • Crystal structure of InNbTiO_6 was amended to be a wolframite-type structure. • Composition-driven phase transformation of In_1_−_xNb_1_−_xTi_2_xO_4 was investigated.

Characterization of hydrothermally synthesized SnS nanoparticles for solar cell application

Science.gov (United States)

Rajwar, Birendra Kumar; Sharma, Shailendra Kumar

2018-05-01

In the present study, SnS nanoparticles were synthesized by simple hydrothermal method using stannous chloride and thiourea as tin (Sn) and sulfur (S) precursor respectively. Synthesized nanoparticles were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy and UV-Vis Spectroscopy techniques. XRD pattern reveals that as-prepared nanoparticles exhibit orthorhombic structure. Average particles size was calculated using Scherrer's formula and found to be 23 nm. FESEM image shows that the as-prepared nanoparticles are in plate like structure. Direct optical band gap (Eg) of as-synthesized nanoparticles was calculated through UV-Vis Spectroscopy measurement and found to be 1.34 eV, which is near to optimum need for photovoltaic solar energy conversion (1.5 eV). Thus this SnS, narrowband gap semiconductor material can be applied as an alternative absorber material for solar cell application.

Accurate solid solution range of BiMnxFe3-xO6 and low temperature magnetism

Science.gov (United States)

Jiang, Pengfei; Yue, Mufei; Cong, Rihong; Gao, Wenliang; Yang, Tao

2017-11-01

BiMnxFe3-xO6 (x = 1) represents a new type of oxide structure containing Bi3+ and competing magnetic super-exchanges. In literature, multiple magnetic states were realized at low temperatures in BiMnFe2O6, and the hypothetical parent compounds (BiMn3O6, BiFe3O6) were predicted to be different in magnetism. Herein, we performed a careful study on the syntheses of BiMnxFe3-xO6 at ambient pressure, and the solid solution range was determined to be 0.9 ≤ x ≤ 1.3 by Rietveld refinements on high-quality powder X-ray diffraction data. Due to the very similar cationic size of Mn3+ and Fe3+, and possibly the structural rigidity, there was no significant structure change in the whole range of solid solution. The magnetic behavior of BiMnxFe3-xO6 (x = 1.2, 1.22, 1.26, 1.28 and 1.3) was generally similar to BiMnFe2O6, while the relative higher concentration of Mn3+ led to the decreasing of the antiferromagnetic ordering temperature.

Biomedical applications of green synthesized Nobel metal nanoparticles.

Science.gov (United States)

Khan, Zia Ul Haq; Khan, Amjad; Chen, Yongmei; Shah, Noor S; Muhammad, Nawshad; Khan, Arif Ullah; Tahir, Kamran; Khan, Faheem Ullah; Murtaza, Behzad; Hassan, Sadaf Ul; Qaisrani, Saeed Ahmad; Wan, Pingyu

2017-08-01

Synthesis of Nobel metal nanoparticles, play a key role in the field of medicine. Plants contain a substantial number of organic constituents, like phenolic compounds and various types of glycosides that help in synthesis of metal nanoparticles. Synthesis of metal nanoparticles by green method is one of the best and environment friendly methods. The major significance of the green synthesis is lack of toxic by-products produced during metal nanoparticle synthesis. The nanoparticles, synthesized by green method show various significant biological activities. Most of the research articles report the synthesized nanoparticles to be active against gram positive and gram negative bacteria. Some of these bacteria include Escherichia coli, Bacillus subtilis, Klebsiella pneumonia and Pseudomonas fluorescens. The synthesized nanoparticles also show significant antifungal activity against Trichophyton simii, Trichophyton mentagrophytes and Trichophyton rubrum as well as different types of cancer cells such as breast cancer cell line. They also exhibit significant antioxidant activity. The activities of these Nobel metal nano-particles mainly depend on the size and shape. The particles of small size with large surface area show good activity in the field of medicine. The synthesized nanoparticles are also active against leishmanial diseases. This research article explores in detail the green synthesis of the nanoparticles and their uses thereof. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of precursor on the morphology and size of ZrO{sub 2} nanoparticles, synthesized by sol-gel method in non-aqueous medium

Energy Technology Data Exchange (ETDEWEB)

Siddiqui, Mohammed Rafiq Hussain; Al-Wassil, Abdulaziz Ibrahim; Mahfouz, Refaat Mohamad [King Saud University, Riyadh (Saudi Arabia). Department of Chemistry, College of Science; Al-Otaibi, Abdullah Mohmmed [King Abdulaziz City for Science and Technology (Saudi Arabia). The NationalProgram for Advanced Materials and Building Systems

2012-11-15

Pure zirconium oxide (ZrO{sub 2}) nanoparticles with diameters 10-25 nm were synthesized from ZrOCl{sub 2}.8H{sub 2}O and Zr(SO{sub 4})2.H{sub 2}O with benzyl alcohol as non-aqueous solvent medium using sol-gel method. Sodium lauryl sulfate was added as surfactants to control the particle size. The synthesized ZrO{sub 2} nanoparticles have a mixture of tetragonal and monoclinic structure. The XRD showed the purity of obtained ZrO{sub 2} nanoparticles with tetragonal and monoclinic phase and the crystallite size for ZrOCl{sub 2}.8H{sub 2}O precursor was estimated to be 18.1 nm and that from Zr(SO{sub 4})2.H{sub 2}O was 9.7 nm. The transmission electron microscopy and scanning electron microscopic studies also shows different sizes of nanoparticles and different morphology depending on the precursor used for the synthesis of ZrO{sub 2} nanoparticles. (author)

Characterization of thin films of the solid electrolyte Li(x)Mg(1-2x)Al(2+x)O4 (x = 0, 0.05, 0.15, 0.25).

Science.gov (United States)

Put, Brecht; Vereecken, Philippe M; Mees, Maarten J; Rosciano, Fabio; Radu, Iuliana P; Stesmans, Andre

2015-11-21

RF-sputtered thin films of spinel Li(x)Mg(1-2x)Al(2+x)O4 were investigated for use as solid electrolyte. The usage of this material can enable the fabrication of a lattice matched battery stack, which is predicted to lead to superior battery performance. Spinel Li(x)Mg(1-2x)Al(2+x)O4 thin films, with stoichiometry (x) ranging between 0 and 0.25, were formed after a crystallization anneal as shown by X-ray diffraction and transmission electron microscopy. The stoichiometry of the films was evaluated by elastic recoil detection and Rutherford backscattering and found to be slightly aluminum rich. The excellent electronic insulation properties were confirmed by both current-voltage measurements as well as by copper plating tests. The electrochemical stability window of the material was probed using cyclic voltammetry. Lithium plating and stripping was observed together with the formation of a Li-Pt alloy, indicating that Li-ions passed through the film. This observation contradicted with impedance measurements at open circuit potential, which showed no apparent Li-ion conductivity of the film. Impedance spectroscopy as a function of potential showed the occurrence of Li-ion intercalation into the Li(x)Mg(1-2x)Al(2+x)O4 layers. When incorporating Li-ions in the material the ionic conductivity can be increased by 3 orders of magnitude. Therefore it is anticipated that the response of Li(x)Mg(1-2x)Al(2+x)O4 is more adequate for a buffer layer than as the solid electrolyte.

Control of the shape and size of iron oxide (α-Fe2O3 nanoparticles synthesized through the chemical precipitation method

Directory of Open Access Journals (Sweden)

Abdelmajid Lassoued

Full Text Available Hematite (α-Fe2O3 nanoparticles were synthesized via a simple chemical precipitation method. The impact of varying the concentration of precursor on the crystalline phase, size and morphology of α-Fe2O3 products was explored. The characteristic of the synthesized hematite nanoparticles were evaluated by X-ray diffraction (XRD, Transmission Electron Microscopy (TEM, Scanning Electron Microscopy (SEM, Fourier Transform Infra-Red (FT-IR spectroscopy, Raman spectroscopy, Differential Thermal Analysis (DTA, Thermo Gravimetric Analysis (TGA, Ultraviolet–Visible (UV–Vis analysis and Photoluminescence (PL. XRD data revealed a rhombohedral (hexagonal structure with the space group R-3c in all samples. Uniform spherical like morphology was confirmed by TEM and SEM. The result revealed that the particle sizes were varied between 21 and 82 nm and that the increase in precursor concentration (FeCl3, 6H2O is accompanied by an increase in the particle size of 21 nm for pure α-Fe2O3 synthesized with [Fe3+] = 0.05 M at 82 nm for pure α-Fe2O3 synthesized with [Fe3+] = 0.4 M. FT-IR confirms the phase purity of the nanoparticles synthesized. The Raman spectroscopy was used not only to prove that we have synthesized pure hematite but also to identify their phonon modes. The thermal behavior of compound was studied by using TGA/DTA results: The TGA showed three mass losses, whereas DTA resulted in three endothermic peaks. Besides, the optical investigation revealed that samples have an optical gap of about 2.1 eV and that this value varies as a function of the precursor concentration. Keywords: Nanoparticles, Hematite (α-Fe2O3, Precipitation, Precursor, Size, Band gap

Effect of hydrogen on the microstructure and electrochemical properties of Si nanoparticles synthesized by microwave plasma

Energy Technology Data Exchange (ETDEWEB)

Koo, Jeongboon; Lee, Jeongeun; Kim, Joonsoo; Jang, Boyun, E-mail: byjang@kier.re.kr

2016-09-01

We synthesized silicon (Si) nanoparticles using an atmospheric microwave plasma process, and investigated the effects of hydrogen (H{sub 2}) injection on their microstructure during the synthesis. Two nozzles were applied to inject H{sub 2} (swirling and rectilinear H{sub 2}). Our microstructural analysis indicated that the amount and method of H{sub 2} injection were critical for completion of the reaction from silicon tetrachloride (SiCl{sub 4}) to Si, as well as to obtain highly crystalline Si nanoparticles. The swirling H{sub 2} was especially critical due to its formation of vortex flow, which allowed relatively long residence time of the H-ions in plasma. The Si nanoparticles synthesized by the atmospheric plasma process had core-shell structures that consisted of crystalline Si cores with amorphous SiO{sub x} shells of 5–15 nm thickness. We also investigated the feasibility of the synthesized Si nanoparticles as anode materials in a lithium-ion battery (LIB). For the core-shell structured Si nanoparticles, we obtained the first reversible capacity of 1204 mAhg{sup −1}, and a capacity retention of 82.2% at the 50{sup th} cycle. - Highlights: • We synthesized Si nanoparticles by an atmospheric microwave plasma process. • We investigated the effects of injected H{sub 2} on the microstructures of Si nanoparticles. • Swirling H{sub 2} was critical, due to the formation of vortex flow in plasma. • The synthesized Si nanoparticles had core (crystalline Si)-shell (SiO{sub x}) structures. • The electrochemical properties depend on its core-shell structures as LIB anode.

Study on magnetite nanoparticles synthesized by chemical method

International Nuclear Information System (INIS)

Pei Wenli; Kumada, H.; Natusme, T.; Saito, H.; Ishio, S.

2007-01-01

Magnetite nanoparticles with controlled size were synthesized by chemical method. Higher deposition temperature and a rapid-raising temperature procedure are favorable to particle size distribution and fabrication of monodisperse nanoparticles. The larger nanoparticles can be synthesized by the two-step method. The large nanoparticle (up to 25 nm) without agglomeration was successfully produced. The saturation magnetization of 11 nm magnetite particles was 45 emu/g at room temperature, which is smaller than that of bulk magnetite due to surface effect. Hysteresis of the magnetite nanoparticle was very small, indicating superparamagnetic behavior. The magnetic domains of the 11 nm magnetite nanoparticles were successfully observed by MFM

Electron spin resonance in Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles synthesized with the thermal decomposition method

Energy Technology Data Exchange (ETDEWEB)

Edelman, I.S., E-mail: ise@iph.krasn.ru [Kirensky Institute of Physics, Federal Research Center KSC, Russian Academy of Sciences, Krasnoyarsk 660036 (Russian Federation); Zharkov, S.M.; Pankrats, A.I. [Kirensky Institute of Physics, Federal Research Center KSC, Russian Academy of Sciences, Krasnoyarsk 660036 (Russian Federation); Siberian Federal University, Krasnoyarsk 660041 (Russian Federation); Vorotynov, A.M.; Tugarinov, V.I.; Ivantsov, R.D.; Petrov, D.A. [Kirensky Institute of Physics, Federal Research Center KSC, Russian Academy of Sciences, Krasnoyarsk 660036 (Russian Federation); Velikanov, D.A. [Kirensky Institute of Physics, Federal Research Center KSC, Russian Academy of Sciences, Krasnoyarsk 660036 (Russian Federation); Siberian Federal University, Krasnoyarsk 660041 (Russian Federation); Lin, Chun-Rong; Chen, Chin-Chang; Tseng, Yaw-Teng; Hsu, Hua-Shu [National Pingtung University, Pingtung City, Pingtung County 90003, Taiwan (China)

2017-08-15

Highlights: • Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} nanoparticles were synthesized as (1 1 1) nanocrystalline plates. • Nanoparticles tend to form stacks consisting of plates attached “face to face”. • ESR parameters demonstrate unusual temperature dependences with a kink at 120–130 K. - Abstract: In this paper, we present a study of the electron spin resonance (ESR) of nanoparticles (NPs) of Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} chalcogenides with x = 0, 0.2, and 0.4. NPs were synthesized via the thermal decomposition of metal chloride salts and selenium powder in a high-temperature organic solvent. According to the XRD and HRTEM data, the NPs were single crystalline nearly hexagonal plates with the structure close to CuCr{sub 2}Se{sub 4} (Fd-3m, a = 10.337 Å). For x = 0 and 0.2, the NPs tend to form long stacks consisting of the plates “face to face” attached to each other due to the magnetostatic interparticle interaction. Only separate NPs were observed in the case of x = 0.4. Peculiarities were revealed in the ESR temperature behavior for the NPs with x = 0 and 0.2 consistent with the features in the temperature dependences of the NPs magnetization. The non-monotonous dependence of the resonance field H{sub res} on the temperature with a kink near 130 K and the energy gap in the resonance spectrum depending on the type of nanoparticle compacting are the distinct peculiarities. One of the main factors is discussed in order to explain the peculiarities: the coexistence of two types of anisotropy in the Cu{sub 1−x}Fe{sub x}Cr{sub 2}Se{sub 4} NPs, in-plain shape anisotropy and magnetocrystalline anisotropy with four easy axes, which increases strongly with the temperature decrease.

Mn-substituted perovskites RECoxMn1-xO3: a comparison between magnetic properties of LaCoxMn1-xO3 and GdCoxMn1-xO3

Directory of Open Access Journals (Sweden)

Barahona, P.

2008-08-01

Full Text Available Cooperative phenomena constitute important mechanisms to explain the magnetic properties of the perovskite manganites REMnO3, in which the rare-earth and/or Mn is partially replaced by divalent elements. In this way, the manganese ion changes its valence state (Mn3+ Mn4+, triggering strong magnetic interactions. In this work we describe the case of GdCoxMn1-xO3 (0.0 ≤ x ≤ 1.0 for which the antiferromagnetic interaction between the Gd sublattice and the Mn/Co network leads to a reversal of the magnetic moment at low temperature. No inversion is observed for the LaCoxMn1-xO3 series, in which the ordering temperature may attain a maximum of 235 K for LaCo0.50Mn0.50O3, while it is only 120 K for similar Co/Mn ratio in the case of GdCo0.50Mn0.50O3. Magnetic properties are described in terms of two regimes: one, for x 3 manganite and another one, for x > 0.5, when Mn substitutes Co in the GdCoO3 cobaltite, while the magnetic interactions are maximized at x(Co = 0.50. This hypothesis is discussed in terms of the respective oxidation states of both manganese (Mn3+ / Mn4+ and cobalt (Co2+ / Co3+.El fenómeno cooperativo constituye un importante mecanismo para explicar las propiedades magnéticas de las perovskitas manganitas TRMnO3, en las que el catión de tierra rara, TR, y/o el catión Mn3+ son parcialmente reemplazados por cationes divalentes. Por esta vía el ión de manganeso cambia de estado de valencia (Mn3+ Mn4+, generando fuertes interacciones magnéticas. En el presente trabajo se describe el caso de las soluciones sólidas GdCoxMn1-xO3 (0.0 ≤ x ≤ 1.0 para las que la interacción antiferromagnética entre la subred del Gd3+ y la red Mn/Co lleva a una inversión del momento magnético a baja temperatura. No se ha observado inversión para la serie LaCoxMn1-xO3, en que la temperatura de orden puede alcanzar un máximo de 235K para LaCo0.50Mn0.50O3, mientras que en el caso de GdCo0.50Mn0.50O3, en que sí se observa inversión, la

Electronic and ionic transport in Ce0.8PrxTb0.2-xO2-δ and evaluation of performance as oxygen permeation membranes

DEFF Research Database (Denmark)

Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

2012-01-01

is significantly enhanced relative to that of a Ce0.9Gd0.1O1.95-δ membrane at high oxygen activities of the permeate gas (aO2 an > 10-15) due to the enhanced electronic conductivity of the Ce0.8PrxTb0.2-xO2-δ compounds. Interference between the ionic and electronic flows has a significant positive effect......The electronic conductivity of Ce0.8PrxTb0.2-xO2-δ (x = 0, 0.05, 0.10, 0.15, 0.20) was determined in the oxygen activity range aO2 ≈ 103 to aO2 ≈ 10-17 at 700- 900 °C by means of Hebb-Wagner polarisation. The electronic conductivity of all the Ce0.8PrxTb0.2-xO2-δ compositions was significantly...... enhanced as compared to that of Ce0.9Gd0.1O1.95-δ, and its value was found to increase with increasing Pr/Tb ratio. The ionic mobility of Ce0.8PrxTb0.2-xO2-δ is similar to that of Ce1- 2δGd2δO2-δ at the same oxygen vacancy concentration. The calculated oxygen flux of a Ce0.8PrxTb0.2-xO2-δ membrane...

Thermochemistry of rare earth doped uranium oxides LnxU1-xO2-0.5x+y (Ln = La, Y, Nd)

Science.gov (United States)

Zhang, Lei; Navrotsky, Alexandra

2015-10-01

Lanthanum, yttrium, and neodymium doped uranium dioxide samples in the fluorite structure have been synthesized, characterized in terms of metal ratio and oxygen content, and their enthalpies of formation measured by high temperature oxide melt solution calorimetry. For oxides doped with 10-50 mol % rare earth (Ln) cations, the formation enthalpies from constituent oxides (LnO1.5, UO2 and UO3 in a reaction not involving oxidation or reduction) become increasingly exothermic with increasing rare earth content, while showing no significant dependence on the varying uranium oxidation state. The oxidation enthalpy of LnxU1-xO2-0.5x+y is similar to that of UO2 to UO3 for all three rare earth doped systems. Though this may suggest that the oxidized uranium in these systems is energetically similar to that in the hexavalent state, thermochemical data alone can not constrain whether the uranium is present as U5+, U6+, or a mixture of oxidation states. The formation enthalpies from elements calculated from the calorimetric data are generally consistent with those from free energy measurements.

Biosynthesis of silver nanoparticles synthesized by Aspergillus

Indian Academy of Sciences (India)

In the present study, biosynthesis of silver nanoparticles and its antioxidant, antimicrobial and cytotoxic activities were investigated. Silver nanoparticles were extracellularly synthesized using Aspergillus flavus and the formation of nanoparticles was observed after 72 h of incubation. The results recorded from colour ...

Phase transformations of high-purity PbI{sub 2} nanoparticles synthesized from lead-acid accumulator anodes

Energy Technology Data Exchange (ETDEWEB)

Malevu, T.D., E-mail: malevutd@ufs.ac.za; Ocaya, R.O.; Tshabalala, K.G.

2016-09-01

High-purity hexagonal lead iodide nanoparticles have been synthesized from a depleted sealed lead acid battery anode. The synthesized product was found to consist of the rare 6R polytype form of PbI{sub 2} that is thought to have good potential in photovoltaic applications. We investigate the effects of annealing time and post-melting temperature on the structure and optical properties using 1.5418 Å CuKα radiation. Photoluminescence measurements were done under 150 W/221 nm wavelength xenon excitation. Phase transformation was observed through XRD peaks when annealing time increased from 0.5–5 h. The nanoparticle grain size and inter-planar distance appeared to be independent of annealing time. PL measurements show three broad peaks in a range of 400 nm to 700 nm that are attributed to excitonic, donor–acceptor pair and luminescence bands from the deep levels.

Antiproliferative effect of silver nanoparticles synthesized using amla on Hep2 cell line

Institute of Scientific and Technical Information of China (English)

Fathima Stanley Rosarin; Vadivel Arulmozhi; Samuthira Nagarajan; Sankaran Mirunalini

2013-01-01

Objective: To synthesize silver nanoparticles by amla extract, screen the cytotoxic, oxidative stress and apoptotic effect of silver nanoparticles (AgNPs) on Hep2 cell line (laryngeal carcinoma cells) in vitro, and to compare the effect of Phyllanthus emblica (P. emblica) (amla) with AgNPs synthesized by amla and 5-FU. Methods: AgNPs was synthesized by P. emblica (aqueous extract) and nanoparticles were characterized UV-Vis spec, the presence of biomoloecules of amla capped in AgNPs was found by FT-IR analysis, shape and size were examined by SEM and DLS. Cytotoxicity of experimental drugs was tested to find IC50 value. ROS generation in cells have been measured by DCFH-DA staining, AO-EtBr, Rhodamine-123 staining and DNA fragmentation were performed to assess apoptotic cell death, mitochondrial membrane potential and apoptotic DNA damage, respectively. Oxidative stress was analyzed by measuring lipid peroxides and antioxidants level to understand the cancer cell death by pro-oxidant mechanism.Results:PE-AgNPs was synthesized and confirmed through kinetic behavior of NPs. The shape of PE-AgNPs was spherical and cubic since it was agglomerated, and the nanoparticle surface was complicated. Average particle size distribution of PE-AgNPs was found to be 188 nm. Potent biomolecules of P. emblica such as polyphenols were capped with AgNPs and reduced its toxicity. In cytotoxicity assay the concentration in which the maximum number of cell death was 60 μg/mL and 50 μg/mL for P. emblica (alone) and AgNPs, respectively and IC50 values were fixed as 30 μg/mL and 20 μg/mL. ROS generation, apoptotic morphological changes, mitochondrial depolarization, DNA damage and oxidative stress was observed as more in AgNPs treated cells than in P. emblica (30 μg/mL) (alone) treated cells and 5-FU treated cells gave similar result.Conclusions:The results suggest that the AgNPs are capped with biomolecules of amla enhanced cytotoxicity in laryngeal cancer cells through oxidative

Bactericidal, structural and morphological properties of ZnO2 nanoparticles synthesized under UV or ultrasound irradiation

International Nuclear Information System (INIS)

Colonia, R; Solís, J L; Gómez, M

2014-01-01

Nanoparticles of ZnO 2 were synthesized by a sol–gel method using Zn(CH 3 COO) 2 and H 2 O 2 in an aqueous solution exposed to either ultraviolet (UV) or ultrasound irradiation. X-ray diffraction and scanning electron microscopy showed that the nanostructures consisted of spherical blackberry-like clusters. Nanoparticles fabricated by using UV irradiation had smaller sizes and narrower size distributions than nanoparticles prepared by using ultrasound. Bacillus subtilis (B. subtilis), Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were used as test microorganisms, and the antibacterial activity of the ZnO 2 nanoparticles was studied by use of the well diffusion agar bacteriological test. ZnO 2 nanoparticles synthetized using UV had the best antibacterial properties. The inhibition zone was largest for B. subtilis but was present also for S. aureus and E. coli. (paper)

Method of synthesizing tungsten nanoparticles

Science.gov (United States)

Thoma, Steven G; Anderson, Travis M

2013-02-12

A method to synthesize tungsten nanoparticles has been developed that enables synthesis of nanometer-scale, monodisperse particles that can be stabilized only by tetrahydrofuran. The method can be used at room temperature, is scalable, and the product concentrated by standard means. Since no additives or stabilizing surfactants are required, this method is particularly well suited for producing tungsten nanoparticles for dispersion in polymers. If complete dispersion is achieved due to the size of the nanoparticles, then the optical properties of the polymer can be largely maintained.

Controlling the morphology and properties of solvothermal synthesized Cu2ZnSnS4 nanoparticles by solvent type

International Nuclear Information System (INIS)

Bahramzadeh, Saeid; Abdizadeh, Hossein; Golobostanfard, Mohammad Reza

2015-01-01

Highlights: • CZTS nanoparticles are fabricated by solvothermal method with different solvents. • Different morphologies are achieved by EDA, TETA, EG, and OA solvents. • Property and chelating ability of the solvents have a key role on nanoparticles formation. • TETA and OA are strongly recommended for solar cell applications. - Abstract: The copper–zinc–tin sulfide Cu 2 ZnSnS 4 (CZTS) semiconductors are recently considered as one of the favorable materials for application as absorber layers in solar cells due to their appropriate direct band gap energy and high optical absorption coefficient. In this study, the effect of solvent type on properties of solvothermal synthesized CZTS nanoparticles has been investigated. Ethylenediamine (EDA), triethylenetetramine (TETA), ethylene glycol (EG), and oleic acid (OA) have been used as the solvent. X-ray diffraction technique and Raman spectroscopy confirmed the formation of crystalline CZTS nanoparticles with kesterite crystal structure in these solvents with the exception of EDA, which forms wurtzite crystal structure. Morphological characterizations show that several distinct morphologies including spherical (70–160 nm), nanoplates (∼45 nm thickness and more than 1 μm length), peculiar flower-like particles (with diameter of ∼0.4–1.5 μm), truncated hexagonal disks, irregular particles, and hexagonal microdisks are obtained by varying the solvent type. Optical studies revealed broad absorption of the CZTS particles in the visible region. Compared with other solvents, OA synthesized CZTS particles show higher absorption in the visible region. However, CZTS nanoparticles synthesized by TETA solvent show the most appropriate properties for application as an absorber materials in solar cells due to high crystallinity, low impurity phases, suitable size, and proper band gap energy

Characterizations of diverse mole of pure and Ni-doped α-Fe2O3 synthesized nanoparticles through chemical precipitation route.

Science.gov (United States)

Sivakumar, S; Anusuya, D; Khatiwada, Chandra Prasad; Sivasubramanian, J; Venkatesan, A; Soundhirarajan, P

2014-07-15

In the present study, an attempt has been made for characterization and synthesis of pure and Ni-doped α-Fe2O3 (hematite) nanoparticles by chemical precipitation method. The synthesized products have been studied by X-ray diffraction (X-RD), Fourier transform infrared (FTIR) spectroscopy, UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), vibrating sample magnetometer (VSM) and scanning electron microscopy (SEM) techniques. The estimated average diameter of α-Fe2O3 nanoparticles were calculated by using the Debye-Scherrer equation and established as 31 nm. SEM micrographs showed the surface morphology as well as structures and particles distributions of synthesized samples. The UV-Vis DRS showed the indirect and direct band gap energies of pure and Ni-doped α-Fe2O3, these were reduced from 1.9847 to 1.52 eV and 2.0503 to 1.76 eV respectively. This result suggested the dopant enhanced the semiconducting behavior of iron oxide nanoparticles to an extent proportional to its nickel doped in the α-Fe2O3. Further, the magnetic properties of the pure and doped samples were investigated by vibrating sample magnetometer (VSM) and evaluated the information of pure and doped samples exhibited saturated hysteresis loop at room temperature, which is indicating that the weak ferromagnetism in nature of our synthesized samples. In addition, it has been found from the magnetization hysteresis curves of Ni-doping, resulting from increased the saturation of magnetization and reduced the coercivity of used samples. Therefore, the present study showed the reduction in band gap energies and coercive field for α-Fe2O3 nanoparticles due to nickel doped. Copyright © 2014 Elsevier B.V. All rights reserved.

LaMn1-xFe xO3 and LaMn0.1-xFe0.90Mo x O3 perovskites: synthesis, characterization and catalytic activity in H2O2 reactions

Directory of Open Access Journals (Sweden)

Fabiano Magalhães

2008-09-01

Full Text Available In this work two perovskites were prepared: LaMn1-xFe xO3, and LaMn0.1-x Fe0.90Mo xO3. XRD and Mössbauer spectroscopy suggest the formation of pure phase perovskite with the incorporation of Fe and Mo in the structure. The catalytic activity of these materials was studied in two reactions with H2O2: the decomposition to O2, and the oxidation of the model organic contaminant methylene blue. The perovskite composition strongly affects the catalytic activity, while Fe decreases the H2O2 decomposition Mo strongly improves dye oxidation.

The removal of 2,4-dichlorophenol under visible light irradiation by silver indium sulfide nanoparticles synthesized by microwave

Directory of Open Access Journals (Sweden)

Amir Hossein

2013-04-01

Full Text Available Silver indium sulfide (AgInS2 nanoparticles were synthesized by microwave method. These nanopartricles were characterized by FT-IR, XRD, DRS, SEM and TEM techniques. The band gap energy of 1.96 eV was determined by UV-Vis diffuse reflection spectrum (DRS. The photocatalytic activity was studied by photodegradation reaction of 2,4-dichlorophenol (2,4-DCP under visible light irradiation. The influence of initial concentration, initial solution pH on the degradation percentage of 2,4-DCP and also, the kinetics of photodegradation were investigated. The removal efficiency up to 95% proved the superior capability of AgInS2 (AIS nanoparticles for water purification.

Rietveld structure refinement and elastic properties of MgAlxCrxFe2-2xO4 spinel ferrites

Science.gov (United States)

Thummer, K. P.; Tanna, Ashish R.; Joshi, Hiren H.

2017-05-01

MgAlxCrxFe2-2xO4 (x = 0.1, 03 & 0.6) ferrites are synthesized by solid state reaction method. The Rietveld refinement of X-ray diffraction (XRD) data confirms the cubic spinel structure with Fd3m space group. The Fourier Transform Infrared Transmission Spectroscopy (FTIR) is employed to study elastic properties of present systems at 300K. The force constants for tetrahedral (A) and octahedral (B) sites of the spinel lattice are determined by infrared spectral and X-ray diffraction analysis. The elastic constants like bulk modulus, rigidity modulus, Young's modulus, Poisson's ratio and Debye temperature are determined. The vibrational frequency of both the interstitial sites increases as Al-Cr content increases hence the force constant and elastic moduli for all the samples are found to increase for the present ferrite system.

XO-2b: A HOT JUPITER WITH A VARIABLE HOST STAR THAT POTENTIALLY AFFECTS ITS MEASURED TRANSIT DEPTH

International Nuclear Information System (INIS)

Zellem, Robert T.; Griffith, Caitlin A.; Pearson, Kyle A.; Fitzpatrick, M. Ryleigh; Teske, Johanna K.; Biddle, Lauren I.; Turner, Jake D.; Henry, Gregory W.; Williamson, Michael H.

2015-01-01

The transiting hot Jupiter XO-2b is an ideal target for multi-object photometry and spectroscopy as it has a relatively bright (V-mag = 11.25) K0V host star (XO-2N) and a large planet-to-star contrast ratio (R p /R s ≈ 0.015). It also has a nearby (31.″21) binary stellar companion (XO-2S) of nearly the same brightness (V-mag = 11.20) and spectral type (G9V), allowing for the characterization and removal of shared systematic errors (e.g., airmass brightness variations). We have therefore conducted a multiyear (2012–2015) study of XO-2b with the University of Arizona’s 61″ (1.55 m) Kuiper Telescope and Mont4k CCD in the Bessel U and Harris B photometric passbands to measure its Rayleigh scattering slope to place upper limits on the pressure-dependent radius at, e.g., 10 bar. Such measurements are needed to constrain its derived molecular abundances from primary transit observations. We have also been monitoring XO-2N since the 2013–2014 winter season with Tennessee State University’s Celestron-14 (0.36 m) automated imaging telescope to investigate stellar variability, which could affect XO-2b’s transit depth. Our observations indicate that XO-2N is variable, potentially due to cool star spots, with a peak-to-peak amplitude of 0.0049 ± 0.0007 R-mag and a period of 29.89 ± 0.16 days for the 2013–2014 observing season and a peak-to-peak amplitude of 0.0035 ± 0.0007 R-mag and 27.34 ± 0.21 day period for the 2014–2015 observing season. Because of the likely influence of XO-2N’s variability on the derivation of XO-2b’s transit depth, we cannot bin multiple nights of data to decrease our uncertainties, preventing us from constraining its gas abundances. This study demonstrates that long-term monitoring programs of exoplanet host stars are crucial for understanding host star variability

Effect of surface properties of NiFe2O4 nanoparticles synthesized by dc thermal plasma route on antimicrobial activity

Science.gov (United States)

Bhosale, S. V.; Ekambe, P. S.; Bhoraskar, S. V.; Mathe, V. L.

2018-05-01

The present work reports the role of surface properties of NiFe2O4 nanoparticles on the antimicrobial activity. The NiFe2O4 nanoparticles were synthesized by gas phase condensation and chemical co-precipitation route. These nanoparticles were extensively investigated using X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and electro-kinetic property measurements. The HRTEM was used to analyze surface morphology of nickel ferrite nanoparticles obtained by two different routes. Electro-kinetic properties of the nanoparticles under investigation were recorded, analyzed and correlated with the antimicrobial properties. It was observed that nickel ferrite nanoparticles synthesized by thermal plasma route (NFOTP) formed highly stable colloidal solution as compared to chemically synthesized (NFOCP), as the later tends to agglomerate due to low surface charge. The antimicrobial activity of NiFe2O4 nanoparticles were investigated on two Gram positive bacteria Staphylococcus aureus and Streptococcus pyogenes, two Gram negative bacteria Escherichia coli and Salmonella typhimurium and one fungal species Candida albicans. It was noted that the surface properties of NiFe2O4 particles have revealing effect on the antimicrobial activity. The NFOTP nanoparticles showed significant activity for gram negative E. coli bacteria however no activity was observed for other bacteria's and fungi under study. Moreover NFOCP particles did not show any significant activity for both bacteria's and fungi. Further, antimicrobial activity of nickel ferrite nanoparticles were studied even for different concentration to obtain the minimum inhibition concentration (MIC).

A sol-gel method to synthesize indium tin oxide nanoparticles

Institute of Scientific and Technical Information of China (English)

Xiuhua Li; Xiujuan xu; Xin Yin; Chunzhong Li; Jianrong Zhang

2011-01-01

Transparent conductive indium tin oxide (ITO) nanoparticles were synthesized by a novel sol-gel method.Granulated indium and tin were dissolved in HNO3 and partially complexed with citric acid.A sol-gel process was induced when tertiary butyl alcohol was added dropwise to the above solution.ITO nanoparticles with an average crystallite size of 18.5 nm and surface area of 32.6 m2/g were obtained after the gel was heat-treated at 700 C.The ITO nanoparticles showed good sinterability,the starting sintering temperature decreased sharply to 900 C,and the 1400 C sintered pellet had a density of 98.1 ％ of theoretical density (TD).

The magnetic and colloidal properties of CoFe2O4 nanoparticles synthesized by co-precipitation.

Science.gov (United States)

Gyergyek, Sašo; Drofenik, Miha; Makovec, Darko

2014-01-01

Magnetic CoFe(2)O(4) nanoparticles were synthesized by co-precipitation at 80 °C. This co-precipitation was achieved by the rapid addition of a strong base to an aqueous solution of cations. The investigation of the samples that were quenched at different times after the addition of the base, using transmission electron microscopy (TEM) coupled with energy-dispersive X-ray spectroscopy (EDXS) and X-ray powder diffractometry, revealed the formation of a Co-deficient amorphous phase and Co(OH)(2), which rapidly reacted to form small CoFe(2)O(4) nanoparticles. The nanoparticles grew with the time of aging at elevated temperature. The colloidal suspensions of the nanoparticles were prepared in both an aqueous medium and in a non-polar organic medium, with the adsorption of citric acid and ricinoleic acid on the nanoparticles, respectively. The measurements of the room-temperature magnetization revealed the ferrimagnetic state of the CoFe(2)O(4) nanoparticles, while their suspensions displayed superparamagnetic behaviour.

Comparison on Bactericidal and Cytotoxic Effect of Silver Nanoparticles Synthesized by Different Methods

Science.gov (United States)

Mala, R.; Celsia, A. S. Ruby; Malathi Devi, S.; Geerthika, S.

2017-08-01

Biologically synthesized silver nanoparticle are biocompatible for medical applications. The present work is aimed to synthesize silver nanoparticle using the fruit pulp of Tamarindusindica and to evaluate its antibacterial and anticancer activity against lung cancercell lines. Antibacterial activity was assessed by well diffusion method. Cytotoxicity was evaluated using MTT assay. GC-MS of fruit pulp extract showed the presence of levoglucosenone, n-hexadecanoic acid, 9,12-octadecadienoic acid etc. Antioxidant activity of the fruit pulp was determined by DPPH assay, hydrogen peroxide scavenging assay and lipid peroxidation. The size of biologically synthesized silver nanoparticle varied from 50 nm to 76 nm. It was 59 nm to 98 nm for chemically synthesized silver nanoparticle. Biologically synthesized silver nanoparticle showed 26 mm inhibition zone against E. coli and chemically synthesized silver nanoparticle showed 20 mm. Antioxidant activity of fruit extract by DPPH showed 84 % reduction. The IC 50 of biologically synthesized silver nanoparticle against lung cancer cell lines was 48 µg/ml. It was 95 µg/ml for chemically synthesized silver nanoparticle. The increased activity of biologically synthesized silver nanoparticle was due to its smaller size, stability and the bioactive compounds capping the silver nanoparticle extracted from the fruit extract.

Enhanced photocatalysis, colloidal stability and cytotoxicity of synchrotron X-ray synthesized Au/TiO2 nanoparticles

International Nuclear Information System (INIS)

Liu, Chi-Jen; Yang, Tsung-Yeh; Wang, Chang-Hai; Chien, Chia-Chi; Chen, Shin-Tai; Wang, Cheng-Liang; Leng, Wei-Hua; Hwu, Y.; Lin, Hong-Ming; Lee, Yao-Chang; Cheng, Chia-Liang; Je, J.H.; Margaritondo, G.

2009-01-01

Au/TiO 2 nanocomposite particles were synthesized by a method based on intense X-ray irradiation without adding any reducing agent or stabilizer. The nanocomposite exhibits promising photocatalytic and biological properties at physiologically relevant concentration ([Au] = 0.028 mM, [TiO 2 ] = 0.5 mM). The structure and photocatalysis were examined by X-ray diffraction, electron microscopy and ultraviolet-visible spectroscopy demonstrating that gold nanoparticles of 2-5 nm size were successfully deposited on TiO 2 nanoparticle surfaces. The nanocomposite exhibited good colloidal stability within a typical cellular environment and was nontoxic to cancer cell according to evaluations under controlled conditions. The Au/TiO 2 nanoparticles were also found to enhance the photocatalytic efficiency of UV radiation and even more that of X-ray radiation. In vitro studies indicated that the cell-killing effect under X-ray irradiation is more pronounced with the addition of Au/TiO 2 nanoparticles than of bare TiO 2 nanoparticles.

The effect of green synthesized gold nanoparticles on rice germination and roots

Science.gov (United States)

Tsi Ndeh, Nji; Maensiri, Santi; Maensiri, Duangkamol

2017-09-01

In this paper, gold nanoparticles were synthesized by means of a green approach with Tiliacora triandra leaf extracts under different conditions. No additional reducing or capping agents were employed. The gold nanoparticles were characterized using UV-visible spectrophotometry, transmission electron microscope, x-ray diffraction and Fourier transform infrared spectroscopy. Gold nanoparticles synthesized at temperature of 80 °C were further used to treat rice (Oryza sativa) grains at different concentrations (0, 10, 100, 500, 1000, 2000 mg l-1) for one week. While germination percentages were high (95-98.38%), a slight decrease in root and shoot lengths relative to the control was observed. Phytotoxicity results indicated that the plant synthesized gold nanoparticles were of minimal toxicity to rice seedlings. Increases in cell death, hydrogen peroxide formation and lipid peroxidation in roots and shoots were noted. However, these increases were not statistically significant. The overall results confirmed that Tiliacora triandra synthesized gold nanoparticles are biocompatible and can be potentially used as nanocarriers in agriculture. Contribution at 5th Thailand International Nanotechnology Conference (Nano Thailand-2016), 27-29 November 2016, Nakhon Ratchasima, Thailand.

XO-2b: A HOT JUPITER WITH A VARIABLE HOST STAR THAT POTENTIALLY AFFECTS ITS MEASURED TRANSIT DEPTH

Energy Technology Data Exchange (ETDEWEB)

Zellem, Robert T.; Griffith, Caitlin A. [Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, University of Arizona, Tucson, AZ 85721 (United States); Pearson, Kyle A.; Fitzpatrick, M. Ryleigh; Teske, Johanna K.; Biddle, Lauren I. [Department of Astronomy, Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Turner, Jake D. [Department of Planetary Sciences, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Henry, Gregory W.; Williamson, Michael H., E-mail: rzellem@lpl.arizona.edu, E-mail: griffith@lpl.arizona.edu [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., P.O. Box 9501, Nashville, TN 37209 (United States)

2015-09-01

The transiting hot Jupiter XO-2b is an ideal target for multi-object photometry and spectroscopy as it has a relatively bright (V-mag = 11.25) K0V host star (XO-2N) and a large planet-to-star contrast ratio (R{sub p}/R{sub s} ≈ 0.015). It also has a nearby (31.″21) binary stellar companion (XO-2S) of nearly the same brightness (V-mag = 11.20) and spectral type (G9V), allowing for the characterization and removal of shared systematic errors (e.g., airmass brightness variations). We have therefore conducted a multiyear (2012–2015) study of XO-2b with the University of Arizona’s 61″ (1.55 m) Kuiper Telescope and Mont4k CCD in the Bessel U and Harris B photometric passbands to measure its Rayleigh scattering slope to place upper limits on the pressure-dependent radius at, e.g., 10 bar. Such measurements are needed to constrain its derived molecular abundances from primary transit observations. We have also been monitoring XO-2N since the 2013–2014 winter season with Tennessee State University’s Celestron-14 (0.36 m) automated imaging telescope to investigate stellar variability, which could affect XO-2b’s transit depth. Our observations indicate that XO-2N is variable, potentially due to cool star spots, with a peak-to-peak amplitude of 0.0049 ± 0.0007 R-mag and a period of 29.89 ± 0.16 days for the 2013–2014 observing season and a peak-to-peak amplitude of 0.0035 ± 0.0007 R-mag and 27.34 ± 0.21 day period for the 2014–2015 observing season. Because of the likely influence of XO-2N’s variability on the derivation of XO-2b’s transit depth, we cannot bin multiple nights of data to decrease our uncertainties, preventing us from constraining its gas abundances. This study demonstrates that long-term monitoring programs of exoplanet host stars are crucial for understanding host star variability.

CO gas sensing properties of In_4Sn_3O_1_2 and TeO_2 composite nanoparticle sensors

International Nuclear Information System (INIS)

Mirzaei, Ali; Park, Sunghoon; Sun, Gun-Joo; Kheel, Hyejoon; Lee, Chongmu

2016-01-01

Highlights: • In4Sn3O12–TeO2 composite nanoparticles were synthesized via a facile hydrothermal route. • The response of the In4Sn3O12–TeO2 composite sensor to CO was stronger than the pristine In4Sn3O12 sensor. • The response of the In4Sn3O12–TeO2 composite sensor to CO was faster than the pristine In4Sn3O12 sensor. • The improved sensing performance of the In4Sn3O12–TeO2 nanocomposite sensor is discussed in detail. • The In4Sn3O12-based nanoparticle sensors showed selectivity to CO over NH3, HCHO and H2. - Abstract: A simple hydrothermal route was used to synthesize In_4Sn_3O_1_2 nanoparticles and In_4Sn_3O_1_2–TeO_2 composite nanoparticles, with In(C_2H_3O_2)_3, SnCl_4, and TeCl_4 as the starting materials. The structure and morphology of the synthesized nanoparticles were examined by X-ray diffraction and scanning electron microscopy (SEM), respectively. The gas-sensing properties of the pure and composite nanoparticles toward CO gas were examined at different concentrations (5–100 ppm) of CO gas at different temperatures (100–300 °C). SEM observation revealed that the composite nanoparticles had a uniform shape and size. The sensor based on the In_4Sn_3O_1_2–TeO_2 composite nanoparticles showed stronger response to CO than its pure In_4Sn_3O_1_2 counterpart. The response of the In_4Sn_3O_1_2–TeO_2 composite-nanoparticle sensor to 100 ppm of CO at 200 °C was 10.21, whereas the maximum response of the In_4Sn_3O_1_2 nanoparticle sensor was 2.78 under the same conditions. Furthermore, the response time of the composite sensor was 19.73 s under these conditions, which is less than one-third of that of the In_4Sn_3O_1_2 sensor. The improved sensing performance of the In_4Sn_3O_1_2–TeO_2 nanocomposite sensor is attributed to the enhanced modulation of the potential barrier height at the In_4Sn_3O_1_2–TeO_2 interface, the stronger oxygen adsorption of p-type TeO_2, and the formation of preferential adsorption sites.

Magnetic properties of Fe-oxide and (Fe, Co) oxide nanoparticles synthesized in polystyrene resin matrix

Science.gov (United States)

Rodak, D.; Kroll, E.; Tsoi, G. M.; Vaishnava, P. P.; Naik, R.; Wenger, L. E.; Suryanarayanan, R.; Naik, V. M.; Boolchand, P.

2003-03-01

Magnetic nanoparticles have potential applications ranging from drug delivery and imaging in the medical field to sensing and memory storage in technology. The preparation, structure, and physical properties of iron oxide-based nanoparticles synthesized by ion exchange in a polystyrene resin matrix have been investigated. Employing a synthesis method developed originally by Ziolo, et. al^1, nanoparticles were prepared in a sulfonated divinyl benzene polystyrene resin matrix using various aqueous solutions of (1) FeCl_2, (2) FeCl_3, (3) FeCl2 : 2FeCl3 , (4) 9FeCl2 : CoCl_2, and (5) 4FeCl2 : CoCl_2. Powder x-ray diffraction measurements were used to identify the phases present while transmission electron microscopy was used for particle size distribution determinations. SQUID magnetization measurements (field-cooled and zero-field-cooled) and Fe^57 Mössbauer effect measurements indicate the presence of ferromagnetic iron oxide phases and a superparamagnetic behavior with blocking temperatures (T_B) varying from 50 K to room temperature. Nanoparticles synthesized using a stoichiometric mixture of FeCl2 and FeCl3 exhibit the lowest TB and smallest particle size distribution. The Mössbauer effect measurements have also been used to identify the iron oxides phases present and their relative amounts in the nanoparticles ^1R.F. Ziolo, et al., Science 207, 219 (1992). *Permanent address: Kettering University, Flint, MI 48504

Biogenic silver and gold nanoparticles synthesized using red ginseng root extract, and their applications.

Science.gov (United States)

Singh, Priyanka; Kim, Yeon Ju; Wang, Chao; Mathiyalagan, Ramya; El-Agamy Farh, Mohamed; Yang, Deok Chun

2016-05-01

In the present study, we report a green methodology for the synthesis of silver and gold nanoparticles, using the root extract of the herbal medicinal plant Korean red ginseng. The silver and gold nanoparticles were synthesized within 1 h and 10 min respectively. The nanoparticles generated were not aggregated, and remained stable for a long time, which suggests the nature of nanoparticles. The phytochemicals and ginsenosides present in the root extract assist in reducing and stabilizing the synthesized nanoparticles. The red ginseng root extract-generated silver nanoparticles exhibit antimicrobial activity against pathogenic microorganisms including Vibrio parahaemolyticus, Staphylococcus aureus, Bacillus cereus, and Candida albicans. In addition, the silver nanoparticles exhibit biofilm degrading activity against S. aureus and Pseudomonas aeruginosa. Thus, the present study opens up a new possibility of synthesizing silver and gold nanoparticles in a green and rapid manner using Korean red ginseng root extract, and explores their biomedical applications.

Morphology evolution of ZrB2 nanoparticles synthesized by sol-gel method

International Nuclear Information System (INIS)

Zhang Yun; Li Ruixing; Jiang Yanshan; Zhao Bin; Duan Huiping; Li Junping; Feng Zhihai

2011-01-01

Zirconium diboride (ZrB 2 ) nanoparticles were synthesized by sol-gel method using zirconium n-propoxide (Zr(OPr) 4 ), boric acid (H 3 BO 3 ), sucrose (C 12 H 22 O 11 ), and acetic acid (AcOH). Clearly, it was a non-aqueous solution system at the very beginning of the reactions. Here, AcOH was used as both chemical modifier and solvent to control Zr(OPr) 4 hydrolysis. Actually, AcOH could dominate the hydrolysis by self-produced water of the chemical propulsion, rather than the help of outer water. C 12 H 22 O 11 was selected, since it can be completely decomposed to carbon. Thus, carbon might be accounted precisely for the carbothermal reduction reaction. Furthermore, we investigated the influence of the gelation temperature on the morphology of ZrB 2 particles. Increasing the gelation temperature, the particle shapes changed from sphere-like particles at 65 deg. C to a particle chain at 75 deg. C, and then form rod-like particles at 85 deg. C. An in-depth HRTEM observation revealed that the nanoparticles of ZrB 2 were gradually fused together to evolve into a particle chain, finally into a rod-like shape. These crystalline nature of ZrB 2 related to the gelation temperature obeyed the 'oriented attachment mechanism' of crystallography. - Graphical Abstract: Increasing the gelation temperature, the particle shapes changed from sphere-like particles at 65 deg. C to a particle chain at 75 deg. C, and then form rod-like particles at 85 deg. C. Highlights: → ZrB 2 nanoparticles were synthesized by sol-gel method in an non-aqueous solution system. → AcOH was used as both chemical modifier and solvent to control Zr(OPr) 4 hydrolysis. → C 12 H 22 O 11 was selected since it can be completely decomposed to carbon. → Increasing the gelation temperature, the particles changed from sphere-like to rod-like ones. → Crystalline nature of ZrB 2 obeyed the 'oriented attachment mechanism' of crystallography.

Antibacterial activity of magnetic iron oxide nanoparticles synthesized by laser ablation in liquid

International Nuclear Information System (INIS)

Ismail, Raid A.; Sulaiman, Ghassan M.; Abdulrahman, Safa A.; Marzoog, Thorria R.

2015-01-01

In this study, (50–110 nm) magnetic iron oxide (α-Fe 2 O 3 ) nanoparticles were synthesized by pulsed laser ablation of iron target in dimethylformamide (DMF) and sodium dodecyl sulfate (SDS) solutions. The structural properties of the synthesized nanoparticles were investigated by using Fourier Transform Infrared (FT-IR) spectroscopy, UV–VIS absorption, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The effect of laser fluence on the characteristics of these nanoparticles was studied. Antibacterial activities of iron oxide nanoparticles were tested against Gram-positive; Staphylococcus aureus and Gram-negative; Escherichia coli, Pseudomonas aeruginosa and Serratia marcescens. The results showed a noteworthy inhibition on both bacterial strains. The preparation conditions were found to affect significantly the antibacterial activity of these nanoparticles. The synthesized magnetic nanoparticles were used to capture rapidly S. aureus bacteria under the magnetic field effect. - Highlights: • Synthesis magnetic iron oxide nanoparticles by pulsed laser ablation • Antibacterial activity against Gram-positive and Gram-negative bacteria • Captured magnetic nanoparticles by S. aureus bacteria under effect of magnetic field

Antibacterial activity of magnetic iron oxide nanoparticles synthesized by laser ablation in liquid

Energy Technology Data Exchange (ETDEWEB)

Ismail, Raid A., E-mail: raidismail@yahoo.com [Laser Physics Division, Applied Science Department, University of Technology, Baghdad (Iraq); Sulaiman, Ghassan M. [Biotechnology Division, Applied Science Department, University of Technology, Baghdad (Iraq); Abdulrahman, Safa A. [Laser Physics Division, Applied Science Department, University of Technology, Baghdad (Iraq); Marzoog, Thorria R. [Biotechnology Division, Applied Science Department, University of Technology, Baghdad (Iraq)

2015-08-01

In this study, (50–110 nm) magnetic iron oxide (α-Fe{sub 2}O{sub 3}) nanoparticles were synthesized by pulsed laser ablation of iron target in dimethylformamide (DMF) and sodium dodecyl sulfate (SDS) solutions. The structural properties of the synthesized nanoparticles were investigated by using Fourier Transform Infrared (FT-IR) spectroscopy, UV–VIS absorption, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The effect of laser fluence on the characteristics of these nanoparticles was studied. Antibacterial activities of iron oxide nanoparticles were tested against Gram-positive; Staphylococcus aureus and Gram-negative; Escherichia coli, Pseudomonas aeruginosa and Serratia marcescens. The results showed a noteworthy inhibition on both bacterial strains. The preparation conditions were found to affect significantly the antibacterial activity of these nanoparticles. The synthesized magnetic nanoparticles were used to capture rapidly S. aureus bacteria under the magnetic field effect. - Highlights: • Synthesis magnetic iron oxide nanoparticles by pulsed laser ablation • Antibacterial activity against Gram-positive and Gram-negative bacteria • Captured magnetic nanoparticles by S. aureus bacteria under effect of magnetic field.

Structure and electrochemical properties of Mg2SnO4 nanoparticles synthesized by a facile co-precipitation method

International Nuclear Information System (INIS)

Tang, Hao; Cheng, Cuixia; Yu, Gaige; Liu, Haowen; Chen, Weiqing

2015-01-01

Nanosized Mg 2 SnO 4 has been synthesized by a facile co-precipitation method. The structure and morphology of the as-prepared samples are characterized by X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), fourier Transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). It is found that Mg 2 SnO 4 sample is very sensitive to the aging time of the precursor. The single phase Mg 2 SnO 4 nanoparticles with ∼23 nm can be obtained at 900 °C using the aging 35 min percusor as source. The electrochemical properties of the powder obtained at 900 °C are investigated by galvanostatic discharge-charge tests and cyclic voltammograms (CVs). The initial specific discharge capacity reaches as high as 927.7 mAh g −1 at 0.2 mA cm −2 in 0.05–3.0 V, which indicates that Mg 2 SnO 4 nanoparticles could be a promising candidate of anode material for Li-ion batteries. - Highlights: • Nanosized Mg 2 SnO 4 has been synthesized by a facile co-precipitation method. • We find that Mg 2 SnO 4 sample is very sensitive to the ageing time of the precursor. • The single phase Mg 2 SnO 4 nanoparticles with about 23 nm can be obtained by calcining the ageing 35 min percusor at 900 °C. • The obtained powders show a better electrochemical performance

ARSENIC REMOVAL USING SOL-GEL SYNTHESIZED TITANIUM DIOXIDE NANOPARTICLES

Science.gov (United States)

In this study, the effectiveness of TiO2 nanoparticles in arsenic adsorption was examined. TiO2 particles (LS) were synthesized via sol-gel techniques and characterized for their crystallinity, surface area and pore volume. Batch adsorption studies were perf...

The magnetic characterization of Fe doped TiO{sub 2} semiconducting oxide nanoparticles synthesized by sol–gel method

Energy Technology Data Exchange (ETDEWEB)

Yeganeh, M., E-mail: mahboubeh.yeganeh@yahoo.co.uk [Department of Physics, Kosar University of Bojnord, P.O. Box 94104455 (Iran, Islamic Republic of); Shahtahmasebi, N.; Kompany, A. [Department of Physics, Ferdowsi University of Mashhad (Iran, Islamic Republic of); Karimipour, M. [Department of Physics, Vali-e-Asr University of Rafsanjan (Iran, Islamic Republic of); Razavi, F. [Department of Physics, Brock University (Canada); Nasralla, N.H.S. [Electron Microscope and Thin Film Department, Physics Division, 33 El Buhouth st., Dokki, 12622 Giza (Egypt); Šiller, L. [School of Chemical Engineering and Advanced Materials, Newcastle University, NE1 7RU (United Kingdom)

2017-04-15

In this work Fe doped TiO{sub 2} nanoparticles were synthesized at different Fe/Ti molar ratio from 1% to 5% by sol-gel technique. The post annealing of the samples was carried out at T=400, 600, and 800 °C. HRTEM of the samples revealed that the mean size of the nanoparticles increases from about 8 nm to about 100 nm as the annealing temperature increased. SQUID magnetometry of 1% and 5% Fe doped TiO{sub 2} has shown mixed ferromagnetic and paramagnetic phases within the crystal while ferromagnetic order with T{sub c} about 350 K was only observed in 5% Fe:TiO{sub 2} sample annealed at T=800 °C. The oxygen vacancy mediated ferromagnetic (FM) interaction could be responsible for the observed FM.

Specific features of ZnCdS nanoparticles synthesized in different solvents

Energy Technology Data Exchange (ETDEWEB)

Kyazym-zade, A. G.; Jafarov, M. A., E-mail: maarif.jafarov@mail.ru; Nasirov, E. F.; Jahangirova, C. A.; Jafarli, R. S. [Baku State University (Azerbaijan)

2017-04-15

Stable colloidal solutions of ZnCdS nanoparticles (3–6 nm in diameter) in polyvinyl alcohol, polyethylene glycol, and H{sub 2}O are produced. The size of the synthesized nanoparticles is independent of the relation between precursors. It is shown that stabilization of the particles is defined by the charge-stability factor and can be attained without any additional stabilizing additives. The ZnCdS quantum dots synthesized emit in a wide spectral range from 450 to 600 nm.

Photoluminescent characteristics of ion beam synthesized Ge nanoparticles in thermally grown SiO2 films

International Nuclear Information System (INIS)

Yu, C.F.; Chao, D.S.; Chen, Y.-F.; Liang, J.H.

2013-01-01

Prospects of developing into numerous silicon-based optoelectronic applications have prompted many studies on the optical properties of Ge nanoparticles within a silicon oxide (SiO 2 ) matrix. Even with such abundant studies, the fundamental mechanism underlying the Ge nanoparticle-induced photoluminescence (PL) is still an open question. In order to elucidate the mechanism, we dedicate this study to investigating the correlation between the PL properties and microstructure of the Ge nanoparticles synthesized in thermally grown SiO 2 films. Our spectral data show that the peak position, at ∼3.1 eV or 400 nm, of the PL band arising from the Ge nanoparticles was essentially unchanged under different Ge implantation fluences and the temperatures of the following annealing process, whereas the sample preparation parameters modified or even fluctuated (in the case of the annealing temperature) the peak intensity considerably. Given the microscopically observed correlation between the nanoparticle structure and the sample preparation parameters, this phenomenon is consistent with the mechanism in which the oxygen-deficiency-related defects in the Ge/SiO 2 interface act as the major luminescence centers; this mechanism also successfully explains the peak intensity fluctuation with the annealing temperature. Moreover, our FTIR data indicate the formation of GeO x upon ion implantation. Since decreasing of the oxygen-related defects by the GeO x formation is expected to be correlated with the annealing temperature, presence of the GeO x renders further experimental support to the oxygen defect mechanism. This understanding may assist the designing of the manufacturing process to optimize the Ge nanoparticle-based PL materials for different technological applications

nanoparticles synthesized by citrate precursor m

African Journals Online (AJOL)

user

(M=Co, Cu) nanoparticles synthesized by citrate precursor method ... The structural characterization was carried out using an X-ray Diffractometer (Rikagu Miniflex, Japan) ..... His current area of interest includes magnetic nanomaterials.

Evaluation of Antioxidant and Cytotoxicity Activities of Copper Ferrite (CuFe2O4 and Zinc Ferrite (ZnFe2O4 Nanoparticles Synthesized by Sol-Gel Self-Combustion Method

Directory of Open Access Journals (Sweden)

Samikannu Kanagesan

2016-08-01

Full Text Available Spinel copper ferrite (CuFe2O4 and zinc ferrite (ZnFe2O4 nanoparticles were synthesized using a sol-gel self-combustion technique. The structural, functional, morphological and magnetic properties of the samples were investigated by Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, Transmission electron microscopy (TEM and vibrating sample magnetometry (VSM. XRD patterns conform to the copper ferrite and zinc ferrite formation, and the average particle sizes were calculated by using a transmission electron microscope, the measured particle sizes being 56 nm for CuFe2O4 and 68 nm for ZnFe2O4. Both spinel ferrite nanoparticles exhibit ferromagnetic behavior with saturation magnetization of 31 emug−1 for copper ferrite (50.63 Am2/Kg and 28.8 Am2/Kg for zinc ferrite. Both synthesized ferrite nanoparticles were equally effective in scavenging 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH free radicals. ZnFe2O4 and CuFe2O4 nanoparticles showed 30.57% ± 1.0% and 28.69% ± 1.14% scavenging activity at 125 µg/mL concentrations. In vitro cytotoxicity study revealed higher concentrations (>125 µg/mL of ZnFe2O4 and CuFe2O4 with increased toxicity against MCF-7 cells, but were found to be non-toxic at lower concentrations suggesting their biocompatibility.

Antibacterial properties of silver nanoparticles synthesized by marine Ochrobactrum sp.

Science.gov (United States)

Thomas, Roshmi; Janardhanan, Anju; Varghese, Rintu T; Soniya, E V; Mathew, Jyothis; Radhakrishnan, E K

2014-01-01

Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and scanning electron microscope (SEM). The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm - 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus.

Antibacterial properties of silver nanoparticles synthesized by marine Ochrobactrum sp.

Directory of Open Access Journals (Sweden)

Roshmi Thomas

2014-12-01

Full Text Available Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM and scanning electron microscope (SEM. The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm - 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus.

High Efficient Dye-Sensitized Solar Cells Based on Synthesized SnO2 Nanoparticles

Directory of Open Access Journals (Sweden)

W. M. N. M. B. Wanninayake

2016-01-01

Full Text Available In this study, SnO2 semiconductor nanoparticles were synthesized for DSC applications via acid route using tin(ii chloride as a starting material and hydrothermal method through the use of tin(iv chloride. Powder X-ray diffraction studies confirmed the formation of the rutile phase of SnO2 with nanoranged particle sizes. A quasi-solid-state electrolyte was employed instead of a conventional liquid electrolyte in order to overcome the practical limitations such as electrolyte leakage, solvent evaporation, and sealing imperfections associated with liquid electrolytes. The gel electrolytes were prepared incorporating lithium iodide (LiI and tetrapropylammonium iodide (Pr4N+I− salts, separately, into the mixture which contains polyacrylonitrile as a polymer, propylene carbonate and ethylene carbonate as plasticizers, iodide/triiodide as the redox couple, acetonitrile as the solvent, and 4-tertiary butylpyridine as an electrolyte additive. In order to overcome the recombination problem associated with the SnO2 due to its higher electron mobility, ultrathin layer of CaCO3 coating was used to cover the surface recombination sites of SnO2 nanoparticles. Maximum energy conversion efficiency of 5.04% is obtained for the device containing gel electrolyte incorporating LiI as the salt. For the same gel electrolyte, the ionic conductivity and the diffusion coefficient of the triiodide ions are 4.70 × 10−3 S cm−1 and 4.31 × 10−7 cm2 s−1, respectively.

Properties of Er{sub 2}O{sub 3} nanoparticles synthesized by a modified co-precipitation method

Energy Technology Data Exchange (ETDEWEB)

Castaneda C, J.; Maranon R, V. F.; Perez Ladron de G, H.; Rodriguez R, R. A.; Chiu Z, R. [Universidad de Guadalajara, Centro Universitario de los Lagos, Av. Enrique Diaz de Leon s/n, Lagos de Moreno 47460, Jalisco (Mexico); Meneses N, M. A., E-mail: jcc050769@yahoo.com.mx [Centro de Investigaciones en Optica, A. C., Apdo. Postal 1-948, Leon, Guanajuato (Mexico)

2015-07-01

Er{sub 2}O{sub 3} nanoparticles were synthesized by co-precipitation with the addition of ascorbate as stabilizing agent. The nanoparticles had spherical shapes with a mean diameter of 32 nm and were allocated in clusters, as determined by X-ray diffraction, atomic force microscopy and optical microscopy. Characteristic green and red emissions from Er{sup 3+} were recorded by pumping the nanoparticles at 525 nm, 805 nm and 975 nm. However, the luminescence spectra show an enhancement of red emission for Nir pump wavelengths. We proposed this behavior was due to phonon-assisted depopulation mechanisms and energy transfer processes related to the different excitation schemes. (Author)

Monodisperse Silver Nanoparticles Synthesized by a Microwave-Assisted Method

International Nuclear Information System (INIS)

Shao-Peng, Zhu; Shao-Chun, Tang; Xiang-Kang, Meng

2009-01-01

Silver nanoparticles with an average size of about 20 nm are synthesized in a colloidal solution with the aid of microwave irradiation. Neither additional reductant nor stabilizer is required in this microwave-assisted method. The color of the colloidal solution is found to be dark green, different from the characteristic yellow of silver colloidal solutions. The silver nanoparticles in the colloidal solution have a narrow size distribution and large yield quantity. UV-visible absorption spectroscopy analysis reveals that the as-synthesized monodisperse silver nanoparticles have exceptional optical properties. Raman spectroscopy measurements demonstrate that these silver nanoparticles exhibit a notable surface-enhanced Raman scattering ability. (cross-disciplinary physics and related areas of science and technology)

Enhanced photocatalysis, colloidal stability and cytotoxicity of synchrotron X-ray synthesized Au/TiO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Liu, Chi-Jen; Yang, Tsung-Yeh; Wang, Chang-Hai [Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan (China); Chien, Chia-Chi [Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan (China); Department of Engineering Science and System, National Tsing Hua University, Hsinchu 300, Taiwan (China); Chen, Shin-Tai; Wang, Cheng-Liang; Leng, Wei-Hua [Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan (China); Hwu, Y., E-mail: phhwu@sinica.edu.tw [Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan (China); Department of Engineering Science and System, National Tsing Hua University, Hsinchu 300, Taiwan (China); Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung 202, Taiwan (China); National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan (China); Lin, Hong-Ming [Department of Materials Engineering, Tatung University, Taipei 10461, Taiwan (China); Lee, Yao-Chang [National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan (China); Cheng, Chia-Liang [Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan (China); Je, J.H. [X-ray Imaging Center, Pohang University of Science and Technology, Pohang (Korea, Republic of); Margaritondo, G. [Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

2009-09-15

Au/TiO{sub 2} nanocomposite particles were synthesized by a method based on intense X-ray irradiation without adding any reducing agent or stabilizer. The nanocomposite exhibits promising photocatalytic and biological properties at physiologically relevant concentration ([Au] = 0.028 mM, [TiO{sub 2}] = 0.5 mM). The structure and photocatalysis were examined by X-ray diffraction, electron microscopy and ultraviolet-visible spectroscopy demonstrating that gold nanoparticles of 2-5 nm size were successfully deposited on TiO{sub 2} nanoparticle surfaces. The nanocomposite exhibited good colloidal stability within a typical cellular environment and was nontoxic to cancer cell according to evaluations under controlled conditions. The Au/TiO{sub 2} nanoparticles were also found to enhance the photocatalytic efficiency of UV radiation and even more that of X-ray radiation. In vitro studies indicated that the cell-killing effect under X-ray irradiation is more pronounced with the addition of Au/TiO{sub 2} nanoparticles than of bare TiO{sub 2} nanoparticles.

Efficacy of plant-mediated synthesized silver nanoparticles against hematophagous parasites.

Science.gov (United States)

Jayaseelan, Chidambaram; Rahuman, Abdul Abdul; Rajakumar, Govindasamy; Santhoshkumar, Thirunavukkarasu; Kirthi, Arivarasan Vishnu; Marimuthu, Sampath; Bagavan, Asokan; Kamaraj, Chinnaperumal; Zahir, Abdul Abduz; Elango, Gandhi; Velayutham, Kanayairam; Rao, Kokati Venkata Bhaskara; Karthik, Loganathan; Raveendran, Sankariah

2012-08-01

The purpose of the present study was to investigate the acaricidal and larvicidal activity against the larvae of Haemaphysalis bispinosa Neumann (Acarina: Ixodidae) and larvae of hematophagous fly Hippobosca maculata Leach (Diptera: Hippoboscidae) and against the fourth-instar larvae of malaria vector, Anopheles stephensi Liston, Japanese encephalitis vector, Culex tritaeniorhynchus Giles (Diptera: Culicidae) of synthesized silver nanoparticles (AgNPs) utilizing aqueous leaf extract from Musa paradisiaca L. (Musaceae). The color of the extract changed to light brown within an hour, and later it changed to dark brown during the 30-min incubation period. AgNPs results were recorded from UV-vis spectrum at 426 nm; Fourier transform infrared (FTIR) analysis confirmed that the bioreduction of Ag(+) ions to silver nanoparticles are due to the reduction by capping material of plant extract, X-ray diffraction (XRD) patterns clearly illustrates that the nanoparticles formed in the present synthesis are crystalline in nature and scanning electron microscopy (SEM) support the biosynthesis and characterization of AgNPs with rod in shape and size of 60-150 nm. After reaction, the XRD pattern of AgNPs showed diffraction peaks at 2θ = 34.37°, 38.01°, 44.17°, 66.34° and 77.29° assigned to the (100), (111), (102), (110) and (120) planes, respectively, of a faced centre cubic (fcc) lattice of silver were obtained. For electron microscopic studies, a 25 μl sample was sputter-coated on copper stub, and the images of nanoparticles were studied using scanning electron microscopy. The spot EDX analysis showed the complete chemical composition of the synthesized AgNPs. The parasite larvae were exposed to varying concentrations of aqueous extract of M. paradisiaca and synthesized AgNPs for 24 h. In the present study, the percent mortality of aqueous extract of M. paradisiaca were 82, 71, 46, 29, 11 and 78, 66, 38, 31and 16 observed in the concentrations of 50, 40, 30, 20, 10 mg

Raman scattering and band-gap variations of Al-doped ZnO nanoparticles synthesized by a chemical colloid process

International Nuclear Information System (INIS)

Lo, Shih-Shou; Huang, Dison; Tu, Chun Hsiang; Hou, Chia-Hung; Chen, Chii-Chang

2009-01-01

This study synthesizes Al-doped ZnO (AZO) nanoparticles using a chemical colloid process. Raman scattering analysis shows that Al doping increases the lattice defects and induces Raman vibration modes of 651 cm -1 . The Raman shift of the active mode E 2 (high) of AZO nanoparticles shows the presence and increase in the stress in nanoparticles when the Al dopant concentration increases. Room-temperature photoluminescence (RT-PL) spectra of synthesized AZO nanoparticles exhibit strong UV emissions near the band edges. The RT-PL peak shifts to a higher photon energy region as the Al concentration increases, indicating a broadening of the band gap.

The Analysis of Silver Nanoparticles After the Manipulation of Synthesis Parameters and with the Addition of Potassium 2-(9-Carboxy-1-Octylnonylsulfanyl)-Malonate

International Nuclear Information System (INIS)

Chin, S.Y.; Hakam, M.A.O.; Goh, S.C.; Yarmo, M.A.

2011-01-01

This research aimed to synthesize and characterize silver nanoparticles by manipulating the parameters involved in stabilizing the particles. The silver nanoparticles in this research were synthesized by reduction process of silver nitrate (AgNO 3 ) with sodium borohydrate (NaBH 4 ) as the reducing agent. The addition of potassium 2- (9-carboxy-1-octylnonylsulfanyl)-malonate into silver nanoparticles solution functioned as a stabilizing agent. The parameters involved in this research were the effect of time towards stability of silver nanoparticles, the effect of addition of potassium 2-(9-carboxy-1-octylnonylsulfanyl)- malonate and the pH level effect towards the synthesized silver nanoparticles. Based on the results obtained from Transmission Electron Microscopy (TEM), we have observed that the incorporation of potassium 2-(9-carboxy-1- octyl-nonanesulfonyl)-malonate as the stabilizing agent can prevent the agglomeration of silver nanoparticles within 16 days which is a breakthrough for the synthesis of silver nanoparticles by using sodium borohydride. The micrograph showed that the size of silver nanoparticles synthesized were within the range of 1.5 nm to 8.3 nm. In addition to that, Dynamic Light Scattering (DLS) technique was used in this research to measure the average size of the silver nanoparticles which stabilized with potassium 2-(9-carboxy-1-octyl-nonanesulfonyl)-malonate. X-Ray Diffraction (XRD) analysis was carried out to view the effect of manipulated pH level on crystalline silver nanoparticles structure. The XRD diffractogram showed the diffraction peaks which can be indexed to planes of face- centered cubic (fcc) of pure silver. (author)

Spatial atmospheric atomic layer deposition of alxzn1-xo

NARCIS (Netherlands)

Illiberi, A.; Scherpenborg, R.; Wu, Y.; Roozeboom, F.; Poodt, P.

2013-01-01

The possibility of growing multicomponent oxides by spatial atmospheric atomic layer deposition has been investigated. To this end, Al xZn1-xO films have been deposited using diethyl zinc (DEZ), trimethyl aluminum (TMA), and water as Zn, Al, and O precursors, respectively. When the metal precursors

A novel hydrothermal approach for synthesizing α-Fe2O3, γ-Fe2O3 and Fe3O4 mesoporous magnetic nanoparticles

International Nuclear Information System (INIS)

Jayanthi, S. Amala; Nathan, D. Muthu Gnana Theresa; Jayashainy, J.; Sagayaraj, P.

2015-01-01

A novel method to synthesize the three phases of iron oxide nanoparticles (hematite, maghemite and magnetite) using the same non-toxic inorganic precursors via a water–organic interface under the low temperature hydrothermal conditions is reported. The synthesized particles are characterized by Powder X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). The Brunauer–Emmett–Teller (BET) results reveal the mesoporous nature of the particles. The magnetic properties of the nanoparticles are studied by Vibrating Sample Magnetometer (VSM) at various low temperatures and also at room temperature. The XRD peaks corresponding to each sample clearly depict the presence of the respective phase of the as-prepared magnetic nanoparticles. The nanoparticles of maghemite and magnetite have saturation magnetization of 58.56 and 40.30 emu/g respectively at room temperature, whereas the particles of hematite possess very low saturation magnetization value of 1.89 emu/g. Further, the magnetization is studied at four different temperatures and the zero field cooled (ZFC) and field cooled (FC) magnetization are reported. - Graphical abstract: Display Omitted - Highlights: • Hematite, maghemite and magnetite are obtained under hydrothermal synthesis. • α-Fe 2 O 3 , γ-Fe 2 O 3 and Fe 3 O 4 prepared are mesoporous and nearly monodisperse. • Near superparamagnetism is observed at room temperature for maghemite and magnetite

Bulk tungsten with uniformly dispersed La2O3 nanoparticles sintered from co-precipitated La2O3/W nanoparticles

International Nuclear Information System (INIS)

Xia, Min; Yan, Qingzhi; Xu, Lei; Guo, Hongyan; Zhu, Lingxu; Ge, Changchun

2013-01-01

Graphical abstract: La 2 O 3 doped La 2 O 3 /W nanoparticles with high-purity and uniform diameters have been fabricated by a co-precipitation process. The as-prepared nanoparticles demonstrate the potential of this method for fabricating uniformly structured bulk tungsten materials. -- Abstract: We report the preparation of 1 wt% La 2 O 3 doped La 2 O 3 /W nanoparticles by a co-precipitation process, using ammonium metatungstate (AMT) and lanthanum nitrate as raw materials. The as-synthesized nanoparticles were characterized by X-ray diffraction, Filed-emission scanning electron microscopy, Transmission electron microscopy (TEM), energy dispersive spectroscopy. Our results reveal that the as-synthesized particles possess uniform diameters of about 70 nm, and are of high purity. The TEM and the corresponding fast Fourier transform images demonstrated that La 2 O 3 precipitates were homogeneously doped into the nano-sized tungsten particles. When the as-synthesized nanoparticles were sintered by spark plasma sintering, the electron backscatter diffraction images of the bulk material reveal that La 2 O 3 nanoparticles were homogenously distributed in both the tungsten grains and the grain boundaries, and the sample exhibit a narrow micro-hardness distribution

Oleic-acid-coated CoFe2O4 nanoparticles synthesized by co-precipitation and hydrothermal synthesis

International Nuclear Information System (INIS)

Gyergyek, Sašo; Drofenik, Miha; Makovec, Darko

2012-01-01

Highlights: ► Synthesis of oleic-acid-coated CoFe 2 O 4 nanoparticles from an aqueous solution. ► During the co-precipitation of Co 2+ /Fe 3+ single-phase spinel forms. ► During the co-precipitation of Co 2+ /Fe 2+ , feroxyhyte forms in addition to spinel. ► Oleic acid increases the spinel formation temperature and limits particle growth. ► Colloidal suspensions of ferrimagnetic CoFe 2 O 4 were prepared. - Abstract: Oleic-acid-coated CoFe 2 O 4 nanoparticles were synthesized by co-precipitation and hydrothermal synthesis. The coprecipitation of the nanoparticles was achieved by the rapid addition of a strong base to an aqueous solution of cations in the presence of the oleic acid surfactant, or without this additive. The nanoparticles were also synthesized by a hydrothermal treatment of suspensions of the precipitates, coprecipitated at room temperature in the presence of the oleic acid, or without it. The influence of the synthesis conditions, such as the valence state of the iron cation in the starting aqueous solution, the temperature of the treatment and the presence of oleic acid, on the particles size was systematically studied. X-ray powder diffractometry (XRD) and transmission electron microscopy (TEM) coupled with energy-dispersive X-ray spectroscopy (EDS) revealed that, although spinel forms at room temperature, a substantial amount of Co was incorporated within the secondary, feroxyhyte-like phase when the iron cation was in the 2+ state. In contrast, when iron was in the 3+ state, the spinel forms at elevated temperatures of approximately 60 °C. The presence of the oleic acid further increased the formation temperature for the stoichiometric spinel. Moreover, the oleic acid impeded the particles’ growth and enabled the preparation of colloidal suspensions of the nanoparticles in non-polar organic solvents. The nanoparticles’ size was successfully controlled by the temperature of the synthesis in the region where superparamagnetism

Curved wall-jet burner for synthesizing titania and silica nanoparticles

KAUST Repository

Ismail, Mohamed

2015-01-01

A novel curved wall-jet (CWJ) burner was designed for flame synthesis, by injecting precursors through a center tube and by supplying fuel/air mixtures as an annular-inward jet for rapid mixing of the precursors in the reaction zone. Titanium dioxide (TiO2) and silicon dioxide (SiO2) nanoparticles were produced in ethylene (C2H4)/air premixed flames using titanium tetraisopropoxide (TTIP) and hexamethyldisiloxane (HMDSO) as the precursors, respectively. Particle image velocimetry measurements confirmed that the precursors can be injected into the flames without appreciably affecting flow structure. The nanoparticles were characterized using X-ray diffraction, Raman spectroscopy, the Brunauer-Emmett-Teller (BET) method, and high-resolution transmission electron microscopy. In the case of TiO2, the phase of nanoparticles could be controlled by adjusting the equivalence ratio, while the particle size was dependent on the precursor loading rate and the flame temperature. The synthesized TiO2 nanoparticles exhibited high crystallinity and the anatase phase was dominant at high equivalence ratios (φ > 1.3). In the case of SiO2, the particle size could be controlled from 11 to 18 nm by adjusting the precursor loading rate. © 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Xanthine oxidase functionalized Ta2O5 nanostructures as a novel scaffold for highly sensitive SPR based fiber optic xanthine sensor.

Science.gov (United States)

Kant, Ravi; Tabassum, Rana; Gupta, Banshi D

2018-01-15

Fabrication and characterization of a surface plasmon resonance based fiber optic xanthine sensor using entrapment of xanthine oxidase (XO) enzyme in several nanostructures of tantalum (v) oxide (Ta 2 O 5 ) have been reported. Chemical route was adopted for synthesizing Ta 2 O 5 nanoparticles, nanorods, nanotubes and nanowires while Ta 2 O 5 nanofibers were prepared by electrospinning technique. The synthesized Ta 2 O 5 nanostructures were characterized by photoluminescence, scanning electron microscopy, UV-Visible spectra and X-ray diffraction pattern. The probes were fabricated by coating an unclad core of the fiber with silver layer followed by the deposition of XO entrapped Ta 2 O 5 nanostructures. The crux of sensing mechanism relies on the modification of dielectric function of sensing layer upon exposure to xanthine solution of diverse concentrations, reflected in terms of shift in resonance wavelength. The sensing probe coated with XO entrapped Ta 2 O 5 nanofibers has been turned out to possess maximum sensitivity amongst the synthesized nanostructures. The probe was optimized in terms of pH of the sample and the concentration of XO entrapped in Ta 2 O 5 nanofibers. The optimized sensing probe possesses a remarkably good sensitivity of 26.2nm/µM in addition to linear range from 0 to 3µM with an invincible LOD value of 0.0127µM together with a response time of 1min. Furthermore, probe selectivity with real sample analysis ensure the usage of the sensor for practical scenario. The results reported open a novel perspective towards a sensitive, rapid, reliable and selective detection of xanthine. Copyright © 2017 Elsevier B.V. All rights reserved.

Bias Voltage-Dependent Impedance Spectroscopy Analysis of Hydrothermally Synthesized ZnS Nanoparticles

Science.gov (United States)

Dey, Arka; Dhar, Joydeep; Sil, Sayantan; Jana, Rajkumar; Ray, Partha Pratim

2018-04-01

In this report, bias voltage-dependent dielectric and electron transport properties of ZnS nanoparticles were discussed. ZnS nanoparticles were synthesized by introducing a modified hydrothermal process. The powder XRD pattern indicates the phase purity, and field emission scanning electron microscope image demonstrates the morphology of the synthesized sample. The optical band gap energy (E g = 4.2 eV) from UV measurement explores semiconductor behavior of the synthesized material. The electrical properties were performed at room temperature using complex impedance spectroscopy (CIS) technique as a function of frequency (40 Hz-10 MHz) under different forward dc bias voltages (0-1 V). The CIS analysis demonstrates the contribution of bulk resistance in conduction mechanism and its dependency on forward dc bias voltages. The imaginary part of the impedance versus frequency curve exhibits the existence of relaxation peak which shifts with increasing dc forward bias voltages. The dc bias voltage-dependent ac and dc conductivity of the synthesized ZnS was studied on thin film structure. A possible hopping mechanism for electrical transport processes in the system was investigated. Finally, it is worth to mention that this analysis of bias voltage-dependent dielectric and transport properties of as-synthesized ZnS showed excellent properties for emerging energy applications.

Microemulsion synthesis and magnetic properties of FexNi(1-x) alloy nanoparticles

Science.gov (United States)

Beygi, H.; Babakhani, A.

2017-01-01

This paper investigates synthesis of FexNi(1-x) bimetallic nanoparticles by microemulsion method. Through studying the mechanism of nanoparticles formation, it is indicated that synthesis of nanoparticles took placed by simultaneous reduction of metal ions and so nanoparticles structure is homogeneous alloy. FexNi(1-x) nanoparticles with different sizes, morphologies and compositions were synthesized by changing the microemulsion parameters such as water/surfactant/oil ratio, presence of co-surfactant and NiCl2·6H2O to FeCl2·4H2O molar ratio. Synthesized nanoparticles were characterized by transmission electron microscopy, particle size analysis, X-ray diffraction, atomic absorption and thermogravimetric analyses. The results indicated that, presence of butanol as co-surfactant led to chain-like arrangement of nanoparticles. Also, finer nanoparticles were synthesized by decreasing the amount of oil and water and increasing the amount of CTAB. The results of vibrating sample magnetometer suggested that magnetic properties of FexNi(1-x) alloy nanoparticles were affected by composition, size and morphology of the particles. Spherical and chain-like FexNi(1-x) alloy nanoparticles were superparamagnetic and ferromagnetic, respectively. Furthermore, higher iron in the composition of nanoparticles increases the magnetic properties.

Surface chemistry and microstructural analysis of CexZr1-xO2-y model catalyst surfaces

International Nuclear Information System (INIS)

Nelson, Alan E.; Schulz, Kirk H.

2003-01-01

Cerium-zirconium mixed metal oxides are widely used as promoters in automotive emissions control catalyst systems (three-way catalysts). The addition of zirconium in the cubic lattice of ceria improves the redox properties and the thermal stability, thereby increasing the catalyst efficiency and longevity. The surface composition and availability of surface oxygen of model ceria-zirconia catalyst promoters was considered to develop a reference for future catalytic reactivity studies. The microstructure was characterized with X-ray diffraction (XRD) to determine the effect of zirconium substitution on crystalline structure and grain size. Additionally, the Ce/Zr surface atomic ratio and existence of Ce 3+ defect sites were examined with X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) for samples with different zirconium concentrations. The surface composition of the model systems with respect to cerium and zirconium concentration is representative of the bulk, indicating no appreciable surface species segregation during model catalyst preparation or exposure to ultrahigh vacuum conditions and analysis techniques. Additionally, the concentration of Ce 3+ defect sites was constant and independent of composition. The quantity of surface oxygen was unaffected by electron bombardment or prolonged exposure to ultrahigh vacuum conditions. Additionally, XRD analysis did not indicate the presence of additional crystalline phases beyond the cubic structure for compositions from 100 to 25 at.% cerium, although additional phases may be present in undetectable quantities. This analysis is an important initial step for determining surface reactions and pathways for the development of efficient and sulfur-tolerant automotive emissions control catalysts

Epitaxial single-crystal thin films of MnxTi1-xO2-δ grown on (rutile)TiO2 substrates with pulsed laser deposition: Experiment and theory

Energy Technology Data Exchange (ETDEWEB)

Ilton, Eugene S.; Droubay, Timothy C.; Chaka, Anne M.; Kovarik, Libor; Varga, Tamas; Arey, Bruce W.; Kerisit, Sebastien N.

2015-02-01

Epitaxial rutile-structured single-crystal MnxTi1-xO2-δ films were synthesized on rutile- (110) and -(001) substrates using pulsed laser deposition. The films were characterized by reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and aberration-corrected transmission electron microscopy (ACTEM). Under the present conditions, 400oC and PO2 = 20 mTorr, single crystal epitaxial thin films were grown for x = 0.13, where x is the nominal average mole fraction of Mn. In fact, arbitrarily thick films could be grown with near invariant Mn/Ti concentration profiles from the substrate/film interface to the film surface. In contrast, at x = 0.25, Mn became enriched towards the surface and a secondary nano-scale phase formed which appeared to maintain the basic rutile structure but with enhanced z-contrast in the tunnels, or tetrahedral interstitial sites. Ab initio thermodynamic calculations provided quantitative estimates for the destabilizing effect of expanding the β-MnO2 lattice parameters to those of TiO2-rutile, the stabilizing effect of diluting Mn with increasing Ti concentration, and competing reaction pathways.

Microstructure, electronic structure and optical properties of combustion synthesized Co doped ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Srinatha, N. [Department of Physics, JB Campus, Bangalore University, Bangalore 560056 (India); Nair, K.G.M. [UGC-DAE-CSR, Kalpakkam Node, Kalpakkam, Kokilamedu 603102 (India); Angadi, Basavaraj, E-mail: brangadi@gmail.com [Department of Physics, JB Campus, Bangalore University, Bangalore 560056 (India)

2015-10-01

We report on the microstructure, electronic structure and optical properties of nanocrystalline Zn{sub 1−x}Co{sub x}O (x=0, 0.01, 0.03, 0.05 and 0.07) particles prepared by solution combustion technique using L-Valine as fuel. The detailed structural and micro-structural studies were carried out by XRD, HRTEM and TEM-SAED respectively, which confirms the formation of single phased, nano-sized particles. The electronic structure was determined through NEXAFS and atomic multiplet calculations/simulations performed for various symmetries and valence states of ‘Co’ to determine the valance state, symmetry and crystal field splitting. The correlations between the experimental NEXAFS spectra and atomic multiplet simulations, confirms that, ‘Co’ present is in the 2+ valence state and substituted at the ‘Zn’ site in tetrahedral symmetry with crystal field splitting, 10Dq =−0.6 eV. The optical properties and ‘Co’ induced defect formation of as-synthesized materials were examined by using diffuse reflectance and Photoluminescence spectroscopy, respectively. Red-shift of band gap energy (E{sub g}) was observed in Zn{sub 1−x}Co{sub x}O samples due to Co (0.58 Å) substitution at Zn (0.60 Å) site of the host ZnO. Also, in PL spectra, a prominent pre-edge peak corresponds to ultraviolet (UV) emission around 360–370 nm was observed with Co concentration along with near band edge emission (NBE) of the wide band gap ZnO and all samples show emission in the blue region.

Chemical synthesis of Cu2Se nanoparticles at room temperature

International Nuclear Information System (INIS)

Rong, Fengxia; Bai, Yan; Chen, Tianfeng; Zheng, Wenjie

2012-01-01

Graphical abstract: The Cu 2 Se nanoparticles were synthesized by a simple and rapid method at room temperature. The TEM and SEM images show that the Cu 2 Se nanoparticles were spherical. Highlights: ► Cu 2 Se nanoparticles were synthesized by the reaction of nanoSe 0 sol with Cu + ions. ► The Cu 2 Se nanoparticles were spherical with cubic structure and well crystallized. ► Optical and electrochemical properties of Cu 2 Se nanoparticles were observed. ► The formation mechanism of Cu 2 Se nanoparticles was proposed. -- Abstract: A simple and rapid method has been developed to synthesize cuprous selenide (Cu 2 Se) nanoparticles by the reaction of selenium nanoparticles sol with copper sulfate solution containing ascorbic acid at room temperature. Cu 2 Se nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy dispersive X-ray analysis (EDX). The results indicated that Cu 2 Se nanoparticles were cubic crystal structure and spherical with the diameter about 75 nm. The ultraviolet–visible absorption spectrum (UV–vis) and cyclic voltammetry of Cu 2 Se nanoparticles were also investigated. The optical band gap energy of Cu 2 Se nanoparticles was 1.94 eV. On the basis of a series of experiments and characterizations, the formation mechanism of Cu 2 Se nanoparticles was discussed.

Microalgae associated Brevundimonas sp. MSK 4 as the nano particle synthesizing unit to produce antimicrobial silver nanoparticles.

Science.gov (United States)

Rajamanickam, Karthic; Sudha, S S; Francis, Mebin; Sowmya, T; Rengaramanujam, J; Sivalingam, Periyasamy; Prabakar, Kandasamy

2013-09-01

The biosynthesis of silver nanoparticles and its antimicrobial property was studied using bacteria isolated from Spirulina products. Isolated bacteria were identified as Bacillus sp. MSK 1 (JX495945), Staphylococcus sp. MSK 2 (JX495946), Bacillus sp. MSK 3 (JX495947) and Brevundimonas sp. MSK 4 (JX495948). Silver nanoparticles (AgNPs) were synthesized using bacterial culture filtrate with AgNO3. The initial syntheses of Ag nanoparticles were characterized by UV-vis spectrophotometer (by measuring the color change to intense brown). Fourier Transform Infrared Spectroscopy (FTIR) study showed evidence that proteins are possible reducing agents and Energy-dispersive X-ray (EDX) study showing the metal silver as major signal. The structure of AgNPs was determined by Scanning electron microscopy (SEM) and X-ray diffraction (XRD). Synthesized Ag nanoparticles with an average size of 40-65 nm have antimicrobial property against human pathogens like Proteus vulgaris, Salmonella typhi, Vibrio cholera, Streptococcus sp., Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. Among the isolates Brevundimonas sp. MSK 4 alone showed good activity in both synthesis of AgNPs and antimicrobial activity. This work demonstrates the possible use of biological synthesized silver nanoparticles to combat the drug resistant problem. Copyright © 2013 Elsevier B.V. All rights reserved.

Antibacterial activity of silver nanoparticles synthesized from serine

Energy Technology Data Exchange (ETDEWEB)

Jayaprakash, N. [Catalysis and Nanomaterials Research Laboratory, Department of Chemistry, Loyola College, Chennai 600 034 (India); SRM Valliammai Engineering College, Department of Chemistry, Chennai 603 203 (India); Judith Vijaya, J., E-mail: jjvijayaloyola@yahoo.co.in [Catalysis and Nanomaterials Research Laboratory, Department of Chemistry, Loyola College, Chennai 600 034 (India); John Kennedy, L. [Materials Division, School of Advanced Sciences, VIT University, Chennai Campus, Chennai 600 048 (India); Priadharsini, K.; Palani, P. [Department of Center for Advanced Study in Botany, University of Madras, Guindy Campus, Chennai 600 025 (India)

2015-04-01

Silver nanoparticles (Ag NPs) were synthesized by a simple microwave irradiation method using polyvinyl pyrrolidone (PVP) as a capping agent and serine as a reducing agent. UV–Visible spectra were used to confirm the formation of Ag NPs by observing the surface plasmon resonance (SPR) band at 443 nm. The emission spectrum of Ag NPs showed an emission band at 484 nm. In the presence of microwave radiation, serine acts as a reducing agent, which was confirmed by Fourier transformed infrared (FT-IR) spectrum. High-resolution transmission electron microscopy (HR-TEM) and high-resolution scanning electron microscopy (HR-SEM) were used to investigate the morphology of the synthesized sample. These images showed the sphere-like morphology. The elemental composition of the sample was determined by the energy dispersive X-ray analysis (EDX). Selected area electron diffraction (SAED) was used to find the crystalline nature of the Ag NPs. The electrochemical behavior of the synthesized Ag NPs was analyzed by the cyclic voltammetry (CV). Antibacterial experiments showed that the prepared Ag NPs showed relatively similar antibacterial activities, when compared with AgNO{sub 3} against Gram-positive and Gram-negative bacteria. - Highlights: • Microwave irradiation method is used to synthesize silver nanoparticles. • Highly stable silver nanoparticles are produced from serine. • A detailed study of antibacterial activities is discussed. • Formation mechanism of silver microspheres has been proposed.

Optimization of factors affecting hexavalent chromium removal from simulated electroplating wastewater by synthesized magnetite nanoparticles.

Science.gov (United States)

Ataabadi, Mitra; Hoodaji, Mehran; Tahmourespour, Arezoo; Kalbasi, Mahmoud; Abdouss, Majid

2015-01-01

Hexavalent chromium is a mutagen and carcinogen that is of significant concern in water and wastewater. In the present study, magnetite nanoparticles (n-Mag) were investigated as a potential remediation technology for the decontamination of Cr (VI)-contaminated wastewater. Synthesized n-Mag was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and BET-N2 technology. To screen and optimize the factors affecting Cr (VI) removal efficiency by synthesized nanoparticles, Plackett-Burman (PB) and Taguchi experimental designs were used respectively. The crystalline produced n-Mag was in the size range of 60-70 nm and had a specific surface area (SSA) of 31.55 m(2) g(-1). Results of PB design showed that the most significant factors affecting Cr (VI) removal efficiency were initial Cr (VI) concentration, pH, n-Mag dosage, and temperature. In a pH of 2, 20 mg L(-1) of Cr (VI) concentration, 4 g L(-1)of n-Mag, temperature of 40 °C, 220 rpm of shaking speed, and 60 min of contact time, the complete removal efficiency of Cr (VI) was achieved. Batch experiments revealed that the removal of Cr (VI) by n-Mag was consistent with pseudo-second order reaction kinetics. The competition from common coexisting ions such as NO₃(-), SO₄(2-), and Cl(-) were not considerable, unless in the higher concentration of SO₄(2-). These results indicated that the readily synthesized magnetite nanoparticles have promising applications for the removal of Cr (VI) from aqueous solution.

The GAPS programme with HARPS-N at TNG. X. Differential abundances in the XO-2 planet-hosting binary

Science.gov (United States)

Biazzo, K.; Gratton, R.; Desidera, S.; Lucatello, S.; Sozzetti, A.; Bonomo, A. S.; Damasso, M.; Gandolfi, D.; Affer, L.; Boccato, C.; Borsa, F.; Claudi, R.; Cosentino, R.; Covino, E.; Knapic, C.; Lanza, A. F.; Maldonado, J.; Marzari, F.; Micela, G.; Molaro, P.; Pagano, I.; Pedani, M.; Pillitteri, I.; Piotto, G.; Poretti, E.; Rainer, M.; Santos, N. C.; Scandariato, G.; Zanmar Sanchez, R.

2015-11-01

Binary stars hosting exoplanets are a unique laboratory where chemical tagging can be performed to measure the elemental abundances of both stellar components with high accuracy, with the aim to investigate the formation of planets and their subsequent evolution. Here, we present a high-precision differential abundance analysis of the XO-2 wide stellar binary based on high-resolution HARPS-N at TNG spectra. Both components are very similar K-dwarfs and host planets. Since they formed presumably within the same molecular cloud, we expect that they possess the same initial elemental abundances. We investigated whether planets can cause some chemical imprints in the stellar atmospheric abundances. We measure abundances of 25 elements for both stars with a range of condensation temperature TC = 40-1741 K, achieving typical precisions of ~0.07 dex. The northern component shows abundances in all elements higher by +0.067 ± 0.032 dex on average, with a mean difference of +0.078 dex for elements with TC > 800 K. The significance of the XO-2N abundance difference relative to XO-2S is at the 2σ level for almost all elements. We discuss that this result might be interpreted as the signature of the ingestion of material by XO-2N or depletion in XO-2S that is due to locking of heavy elements by the planetary companions. We estimate a mass of several tens of M⊕ in heavy elements. The difference in abundances between XO-2N and XO-2S shows a positive correlation with the condensation temperatures of the elements, with a slope of (4.7 ± 0.9) × 10-5 dex K-1, which could mean that both components have not formed terrestrial planets, but first experienced the accretion of rocky core interior to the subsequent giant planets. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG), operated on the island of La Palma by the INAF - Fundación Galileo Galilei at the Roche de los Muchachos Observatory of the Instituto de Astrofísica de Canarias (IAC) in the

Kinetic study of group IV nanoparticles ion beam synthesized in SiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Bonafos, C. E-mail: bonafos@cemes.fr; Colombeau, B.; Altibelli, A.; Carrada, M.; Ben Assayag, G.; Garrido, B.; Lopez, M.; Perez-Rodriguez, A.; Morante, J.R.; Claverie, A

2001-05-01

Most studies concerning group IV (Si, Ge) ion beam synthesized nanocrystals in SiO{sub 2} have shown that a link exists between the observed physical properties and the characteristics of the 'populations' of nanoparticles (size-distribution, density, volume fraction). The aim of this paper is to study the influence of the initial supersaturation and annealing conditions on these characteristics. For this, experimental methods have been developed, that allow accurate statistical studies. Different transmission electron microscopy (TEM) imaging conditions have been tested and the most adequate ones have been identified for each system. An original method for the measurement of the density of precipitates embedded in an amorphous matrix has been developed and tested for Ge precipitates in SiO{sub 2} and has permitted to evidence a conservative Ostwald ripening during annealing. The kinetic behavior of Si nanoparticles has also been studied by coupling TEM measurements and 'atomistic' simulations. During annealing, the growth of these nanoparticles is very slow but their size significantly increases when increasing the initial Si excess. Simulations are in perfect agreement with experiment when taking into account interaction effects between particles.

Oxide nanoparticle-based fabrication and optical properties of Cu(In1−xGax)S2 absorber layer for solar cells

International Nuclear Information System (INIS)

Choi, Yo-Min; Lee, Young-In; Kim, Bum-Sung; Choa, Yong-Ho

2013-01-01

The compound Cu(In 1−x Ga x )S 2 (CIGS) was synthesized using copper oxide, indium oxide and gallium oxide mixture (CIGO) nanoparticles using salt-assisted ultrasonic spray pyrolysis (SAUSP). Under this method, CIGS can be produced without the complicated restrictions of a vacuum and an inert atmosphere. The band gap of CIGS can be controlled by introducing the desired stoichiometric quantities of starting materials. In order to synthesize CIGO nanoparticles, various NaCl/precursor ratios were used to accomplish the SAUSP process and ultimately monodisperse CIGO nanoparticles with average particle size of 9 nm without hard agglomeration were obtained. Subsequently, the CIGO nanoparticles were sulfurized to form the CIGS in H 2 S/Ar atmosphere at 500 °C. The CIGS obtained in the present study has the various band gap ranging from 1.67 to 2.34 eV depending on the Ga / (In + Ga) ratio, and those band gap correspond to the respective bulk materials. - Highlights: • CIGS is obtained using Cu, In and Ga oxide mixture (CIGO) nanoparticles. • Salt-assisted ultrasonic spray pyrolysis is used to synthesize CIGO nanoparticles. • Nine nanometers of monodisperse CIGO nanoparticles without hard agglomeration is obtained. • The band gap of CIGS can be controlled by introducing the desired ratio of precursor

Syntheses of crosslinked latex nanoparticles using differential microemulsion polymerization

Science.gov (United States)

Hassmoro, N. F.; Rusop, M.; Abdullah, S.

2013-06-01

The differential microemulsion polymerization was used to synthesize latex nanoparticles. In this paper, 1, 3-butylene glycol dimethacrylate (1, 3-BGDMA) was used as a crosslinker respectively 1-5 weight% of monomer total. Butyl acrylate (BA), butyl methacrylate (BMA), and methacrylic acid (MAA) was used as the monomer. The thin film of latex nanoparticles were prepared by using spin coating method and have been dried at 100°C for 5 minutes. The amount of the crosslinker added in the polymerization was optimized and we found that the particle sizes fall in the range of 30-60 nm. The structural morphology of the uncrosslinked latex represented the most homogeneous image compared to the crosslinked latex. The effect of the amount of crosslinker on the particle sizes investigated by the Zeta-sizer Nano series while Atomic Force microscopy (AFM) was used to study the structural properties of latex nanoparticles.

Syntheses of crosslinked latex nanoparticles using differential microemulsion polymerization

International Nuclear Information System (INIS)

Hassmoro, N F; Abdullah, S; Rusop, M

2013-01-01

The differential microemulsion polymerization was used to synthesize latex nanoparticles. In this paper, 1, 3-butylene glycol dimethacrylate (1, 3-BGDMA) was used as a crosslinker respectively 1–5 weight% of monomer total. Butyl acrylate (BA), butyl methacrylate (BMA), and methacrylic acid (MAA) was used as the monomer. The thin film of latex nanoparticles were prepared by using spin coating method and have been dried at 100°C for 5 minutes. The amount of the crosslinker added in the polymerization was optimized and we found that the particle sizes fall in the range of 30–60 nm. The structural morphology of the uncrosslinked latex represented the most homogeneous image compared to the crosslinked latex. The effect of the amount of crosslinker on the particle sizes investigated by the Zeta-sizer Nano series while Atomic Force microscopy (AFM) was used to study the structural properties of latex nanoparticles.

Recent Progress in Syntheses and Applications of Dumbbell-like Nanoparticles**

OpenAIRE

Wang, Chao; Xu, Chenjie; Zeng, Hao; Sun, Shouheng

2009-01-01

This paper reviews the recent research progress in syntheses and applications of dumbbell-like nanoparticles. It first describes the general synthesis of dumbbell-like nanoparticles containing noble metal and magnetic NPs/or quantum dots. It then outlines the interesting optical and magnetic properties found in these dumbbell nanoparticles. The review further highlights several exciting application potentials of these nanoparticles in catalysis and biomedicine.

Antimicrobial and cytotoxicity effect of silver nanoparticle synthesized by Croton bonplandianum Baill. leaves

Directory of Open Access Journals (Sweden)

K. Khanra

2016-01-01

Full Text Available Objective(s: For the development of reliable, ecofriendly, less expensive process for the synthesis of silver nanoparticles and to evaluate the bactericidal, and cytotoxicity properties of silver nanoparticles synthesized from root extract of Croton bonplandianum, Baill. Materials and Methods: The synthesis of silver nanoparticles by plant part of Croton bonplandianum was carried out.  The formation of nanoparticles was confirmed by Transmission Electron Microscopy (TEM, Scanning Electron Microscopy (SEM, XRD and UV-Vis spectrophotometric analysis.  The biochemical properties were assayed by antibacterial study, cytotoxicity assay using cancer cell line.  Results: The formation of silver nanoparticles was confirmed by UV-VIS spectroscopic analysis which showed absorbance peak at 425 nm.  X-ray diffraction photograph indicated the face centered cubic structure of the synthesized AgNPs.  TEM has displayed the different dimensional images of biogenic silver nanoparticles with particle size distribution ranging from 15-40 nm with an average size of 32 nm. Silver particles are spherical in shape, clustered.  The EDX analysis was used to identify the elemental composition of synthesized AgNPs. Antibacterial activity of the synthesized AgNPs against three Gram positive and Gram negative bacteria strains like Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa carried out showed significant zones of inhibition. The cytotoxicity study by AgNPS also showed cytotoxicity on ovarian cancer cell line PA-1 and lung epithelial cancer cell line A549.  Conclusion: The present study confirms that the AgNPs have great promise as antibacterial, and anticancer agent.

Studies on magnetic properties of chemically synthesized crystalline calcium ferrite nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Debnath, A., E-mail: debnathanimesh@gmail.com [Department of Civil Engineering, National Institute of Technology Agartala, Jirania, West Tripura, 799046 India (India); Bera, A.; Saha, B. [Department of Physics, National Institute of Technology Agartala, Jirania, West Tripura 799046 (India); Chattopadhyay, K. K. [Department of Physics, Jadavpur University, Kolkata 700 032 (India)

2016-05-23

Spinel-type ferrites have taken a very important role for modern electronic industry. Most of these ferrites exhibit low-loss dielectric properties, high resistivity, low eddy current and also high temperature ferromagnetism. Calcium ferrite is one such important metal oxide which is environmentally safe, chemically stable, low cost and greatly abundant. This outstanding material of calcium ferrite is synthesized by a simple chemical precipitation method using NaOH as the precipitating agent. Ferric chloride anhydrous (FeCl{sub 3}) and Calcium chloride dihydrate (CaCl{sub 2}.2H{sub 2}O) were used as iron and calcium sources respectively. The samples were heated at 200°C for 8h to obtain homogeneous powder of Calcium ferrite. The powders were characterized by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Transmission electrical microscopy (TEM), and Fourier transform infrared spectroscopic (FTIR) measurements. The polycrystalline nature of the sample was confirmed by X-ray diffraction study. The magnetic properties of the sample were investigated by vibrating sample magnetometer (VSM) measurements. Magnetization curve of the prepared sample depicts that as synthesized calcium ferrite nanoparticles have saturation magnetic moment of 1.74 emu/g and the coercivity of 35.08 Oe with superparamagnetic behavior. The synthesized calcium ferrite nanoparticles with such magnetic properties will be a candidate material for different applications in electronics and exploring its functionality in the field of recently developing semiconductor device physics and spintronics.

Studies on magnetic properties of chemically synthesized crystalline calcium ferrite nanoparticles

International Nuclear Information System (INIS)

Debnath, A.; Bera, A.; Saha, B.; Chattopadhyay, K. K.

2016-01-01

Spinel-type ferrites have taken a very important role for modern electronic industry. Most of these ferrites exhibit low-loss dielectric properties, high resistivity, low eddy current and also high temperature ferromagnetism. Calcium ferrite is one such important metal oxide which is environmentally safe, chemically stable, low cost and greatly abundant. This outstanding material of calcium ferrite is synthesized by a simple chemical precipitation method using NaOH as the precipitating agent. Ferric chloride anhydrous (FeCl_3) and Calcium chloride dihydrate (CaCl_2.2H_2O) were used as iron and calcium sources respectively. The samples were heated at 200°C for 8h to obtain homogeneous powder of Calcium ferrite. The powders were characterized by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Transmission electrical microscopy (TEM), and Fourier transform infrared spectroscopic (FTIR) measurements. The polycrystalline nature of the sample was confirmed by X-ray diffraction study. The magnetic properties of the sample were investigated by vibrating sample magnetometer (VSM) measurements. Magnetization curve of the prepared sample depicts that as synthesized calcium ferrite nanoparticles have saturation magnetic moment of 1.74 emu/g and the coercivity of 35.08 Oe with superparamagnetic behavior. The synthesized calcium ferrite nanoparticles with such magnetic properties will be a candidate material for different applications in electronics and exploring its functionality in the field of recently developing semiconductor device physics and spintronics.

Thermally stimulated current analysis of Zn{sub 1-x}Cd{sub x}O alloy films

Energy Technology Data Exchange (ETDEWEB)

Aybek, A. Senol, E-mail: saybek@anadolu.edu.tr [Department of Physics, Anadolu University, Eskisehir 26470 (Turkey); Baysal, Nihal [Kilicoglu Anadolu High School, Eskisehir 26050 (Turkey); Zor, Muhsin; Turan, Evren; Kul, Metin [Department of Physics, Anadolu University, Eskisehir 26470 (Turkey)

2011-02-03

Research highlights: > We have studied the structural and electrical properties of Zn{sub 1-x}Cd{sub x}O alloy films deposited by ultrasonic spray pyrolysis technique. > The trap energy, the capture cross-section, the attempt-to-escape frequency and the concentration of the traps in Zn{sub 1-x}Cd{sub x}O films are reported. > The effect of the Cd incorporation into ZnO material on trapping levels was investigated by the TSC measurements. Two overlapped peaks were registered at levels of 0.033 and 0.197 eV in ZnO sample by the curve fitting technique. The observed trap energy levels for ZnO film is thought to originate from zinc interstitials and oxygen vacancies. However, the incorporation of Cd into Zn{sub 1-x}Cd{sub x}O alloy films with x = 0.59 have resulted in two trapping centers with activation energies of 0.118 and 0.215 eV. The observed trap levels in Zn{sub 0.41}Cd{sub 0.59}O alloy film are related to oxygen adsorption in the sample. - Abstract: We have studied the structural and electrical properties of Zn{sub 1-x}Cd{sub x}O alloy films deposited by ultrasonic spray pyrolysis technique. XRD measurement indicated that pure ZnO and CdO samples had single phases with hexagonal wurtzite and cubic structures, respectively. However, Zn{sub 1-x}Cd{sub x}O alloy films with x = 0.59 and 0.78 exhibited mixtures of a hexagonal wurtzite ZnO phase and a cubic CdO phase. Analysis of thermally stimulated current spectra of Zn{sub 1-x}Cd{sub x}O alloy films revealed the existence of a number of overlapped peaks each characterized by different trap energy levels located in the range of 0.033-0.215 eV below the conduction band. We have used curve fitting method for the evaluation of the trap parameters of the alloy films. The values of attempt-to-escape frequency {nu}, capture cross-section S and concentration of the traps N{sub t} have been determined.

Synthesizing Zno Nanoparticles by High-Energy Milling and Investigating Their Antimicrobial Effect

Directory of Open Access Journals (Sweden)

N Mohammadi

2015-07-01

Results: The study results demonstrated that size of the synthesized nanoparticles was within the range of 20 -90 nm and their morphology was reported as nanorod and nanoparticles with multifaceted cross-section. An increase in the density of nanoparticles resulted in a rise in the antimicrobial effect. Moreover, Staphylococcus aureus bacteria inhibition zone was 3±0.5 and 7±0.5 mm respectively at the density of 6 and 10 mM. The MIC and MBC of ZnO nanoparticles provided for Staphylococcus aureus were observed 3±3 and 2.5±0 mg/ml, whereas they were reported 7.5±0 and 8±0 mg/ml for Escherichia coli bacteria. Conclusion: The findings of the present study revealed that ZnO nanomaterials could be synthesized by applying high-energy milling on micron-scaled ZnO particles. In addition, they can be utilized in food packaging and preservation process.

Cu2O-directed in situ growth of Au nanoparticles inside HKUST-1 nanocages.

Science.gov (United States)

Liu, Yongxin; Liu, Ting; Tian, Long; Zhang, Linlin; Yao, Lili; Tan, Taixing; Xu, Jin; Han, Xiaohui; Liu, Dan; Wang, Cheng

2016-12-07

Controllable integration of metal nanoparticles (MNPs) and metal-organic frameworks (MOFs) is attracting considerable attention as the obtained composite materials always show synergistic effects in applications of catalysis, delivery, as well as sensing. Herein, a Cu 2 O-directed in situ growth strategy was developed to integrate Au nanoparticles and HKUST-1. In this strategy, Cu 2 O@HKUST-1 core-shell heterostructures, HKUST-1 nanocages, Cu 2 O@Au@HKUST-1 sandwich core-shell heterostructures and Au@HKUST-1 balls-in-cage heterostructures were successfully synthesized. Cu 2 O@HKUST-1 core-shell heterostructures were synthesized by soaking Cu 2 O nanocrystals in benzene-1,3,5-tricarboxylic acid solution. The well-defined Cu 2 O@HKUST-1 core-shell heterostructures were demonstrated to be dominated by the ratio of Cu 2+ cations to btc 3- ligands in solution during the period of HKUST-1 formation. Cu 2 O@Au@HKUST-1 sandwich core-shell or Au@HKUST-1 balls-in-cage heterostructures were obtained by impregnating HAuCl 4 into Cu 2 O@HKUST-1 core-shell heterostructures. Due to the porosity of HKUST-1 and reducibility of Cu 2 O, HAuCl 4 could pass through the HKUST-1 shell and be reduced by the Cu 2 O core in situ forming Au nanoparticles. Finally, CO oxidation reaction at high temperatures was carried out to assess the catalytic functionality of the obtained composite heterostructures. This strategy can circumvent some drawbacks of the existing approaches for integrating MNPs and MOFs, such as nonselective deposition of MNPs at the outer surface of the MOF matrices, extreme treatment conditions and additional surface modifications.

High pressure phase transitions in Mg{sub 1-x}Ca{sub x}O: Theory

Energy Technology Data Exchange (ETDEWEB)

Srivastava, Anurag; Chauhan, Mamta [Advanced Material Research Lab, Indian Institute of Information Technology and Management, Gwalior (India); Singh, R.K. [Department of Physics, ITM University, Gurgaon (India); Padegaonker, Rishikesh [Indian Embassy School, Sana (Yemen)

2011-08-15

We have analysed a B1 {yields} B2 structural phase transitions in Mg{sub 1-x}Ca{sub x}O solid solutions and their ground state properties by using first principle density functional theory and charge transfer interaction potential (CTIP) approach. The effects of exchange-correlation interactions are handled by the generalized gradient approximation with Perdew-Burke-Ernzerhof type parameterization. CTIP approach includes the long range modified Coulomb with charge transfer interactions and short range part of this model includes the van der Waals as well as Hafemeister Flygare type overlap repulsive interactions. The study observes a linear variation of calculated transition pressure, bulk modulus and lattice parameter of Mg{sub 1-x}Ca{sub x}O as a function of Ca composition. The observed results for the end point members are in agreement to their experimental counterparts and the deviations have been discussed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

One pot synthesized Li, Zr doped porous silica nanoparticle for low temperature CO2 adsorption

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Mani Ganesh

2017-05-01

Full Text Available Li, Zr doped porous silica was synthesized in one pot and investigated for low temperature CO2 adsorption. The synthesized nanoparticle was characterized by X-ray diffraction (XRD, N2 adsorption–desorption measurement, thermogravimetric analysis (TGA and scanning electron microscopy (SEM. The specific surface area, average pore diameter and pore volume were determined to be 962 m2/g, 2.3 nm and 0.56 cm3/g respectively. ICP-AES analysis revealed a metal content of 4 wt.% (Zr and 3.42 wt.% (Li. Their CO2 adsorption capacity was tested at room temperature and atmospheric pressure. An uptake of about 5 wt.% was observed and regenerable at a low temperature of 200 °C. This adsorption and desorption temperature of the sorbent is lower than the reported lithium silicate. The CO2 adsorption–desorption cyclic performance studies illustrated that Li, Zr doped porous silica is a recyclable, selective and potential sorbent for CO2 adsorption.

Thermo-selective Tm(x)Ti(1-x)O(2-x/2) nanoparticles: from Tm-doped anatase TiO2 to a rutile/pyrochlore Tm2Ti2O7 mixture. An experimental and theoretical study with a photocatalytic application.

Science.gov (United States)

Navas, Javier; Sánchez-Coronilla, Antonio; Aguilar, Teresa; De los Santos, Desireé M; Hernández, Norge C; Alcántara, Rodrigo; Fernández-Lorenzo, Concha; Martín-Calleja, Joaquín

2014-11-07

This is an experimental and theoretical study of thulium doped TiO2 nanoparticles. From an experimental perspective, a method was used to synthesize thulium-doped TiO2 nanoparticles in which Tm(3+) replaces Ti(4+) in the lattice, which to our knowledge has neither been reported nor studied theoretically so far. Different proportions of anatase and rutile phases were obtained at different annealing temperatures, and XRD and Raman spectroscopy also revealed the presence of a pyrochlore phase (Tm2Ti2O7) at 1173 K. Thus, the structure of the Tm-doped nanoparticles was thermally-controlled. Furthermore, XPS showed the presence of Tm(3+) in the samples synthesized, which produces oxygen vacancies to maintain the local neutrality in the lattice. The presence of Tm(3+) in the samples led to changes in the UV-Vis absorption spectra, so they showed photoluminescence properties and new states in the band gap, which produce a new lower energy electronic transition than the main TiO2 one. Periodic DFT calculations were performed to understand the experimentally produced structures. The production of oxygen vacancies was analysed and the changes generated in the structure were fully detailed. The DOS and PDOS analyses confirmed the experimental results obtained using UV-Vis spectroscopy, and showed that the new electronic states in the band gap are due to interactions of the f state of Tm and the p state of O. Likewise, the charge study and the ELF analysis indicate that when Tm is introduced into the TiO2 structure, the Ti-O bond around the oxygen vacancy is strengthened. Finally, an example of a photocatalytic application was developed to show the high efficiency of the samples due to the heterojunction in the interfaces of the phases in the samples, which improved the charge separation and the good charge carrier mobility due to the presence of the pyrochlore phase, as was also shown theoretically.

Distinction between SnO2 nanoparticles synthesized using co ...

Indian Academy of Sciences (India)

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pared with that of a co-precipitation-modified SnO2 nanoparticles. Keywords. SnO2 nanoparticle ... Dye-sensitized solar cells (DSSCs), which convert light to electricity by means of ... nature, additives and aging time. Nanosized particles pre-.

THERMAL EMISSION AND TIDAL HEATING OF THE HEAVY AND ECCENTRIC PLANET XO-3b

International Nuclear Information System (INIS)

Machalek, Pavel; Greene, Tom; McCullough, Peter R.; Burrows, Adam; Burke, Christopher J.; Hora, Joseph L.; Johns-Krull, Christopher M.; Deming, Drake L.

2010-01-01

We determined the flux ratios of the heavy and eccentric planet XO-3b to its parent star in the four Infrared Array Camera bands of the Spitzer Space Telescope: 0.101% ± 0.004% at 3.6 μm; 0.143% ± 0.006% at 4.5 μm; 0.134% ± 0.049% at 5.8 μm; and 0.150% ± 0.036% at 8.0 μm. The flux ratios are within [-2.2, 0.3, -0.8, and -1.7]σ of the model of XO-3b with a thermally inverted stratosphere in the 3.6 μm, 4.5 μm, 5.8 μm, and 8.0 μm channels, respectively. XO-3b has a high illumination from its parent star (F p ∼ (1.9-4.2) x 10 9 erg cm -2 s -1 ) and is thus expected to have a thermal inversion, which we indeed observe. When combined with existing data for other planets, the correlation between the presence of an atmospheric temperature inversion and the substellar flux is insufficient to explain why some high insolation planets like TrES-3 do not have stratospheric inversions and some low insolation planets like XO-1b do have inversions. Secondary factors such as sulfur chemistry, atmospheric metallicity, amounts of macroscopic mixing in the stratosphere, or even dynamical weather effects likely play a role. Using the secondary eclipse timing centroids, we determined the orbital eccentricity of XO-3b as e = 0.277 ± 0.009. The model radius-age trajectories for XO-3b imply that at least some amount of tidal heating is required to inflate the radius of XO-3b, and the tidal heating parameter of the planet is constrained to Q p ∼ 6 .

Study of structural phase transformation and hysteresis behavior of inverse-spinel α-ferrite nanoparticles synthesized by co-precipitation method

Science.gov (United States)

Dabagh, Shadab; Chaudhary, Kashif; Haider, Zuhaib; Ali, Jalil

2018-03-01

Substitution of cobalt (Co2+) ions in cobalt ferrite (CoFe2O4) with copper (Cu2+) and aluminum (Al3+) ions allows variations in their electric and magnetic properties which can be optimized for specific applications. In this article, synthesis of inverse-spinel Co1-xCuxFe2-xAlxO4 (0.0 ≤ x ≤ 0.8) nanoparticles by substituting Cu2+ and Al3+ ions in CoFe2O4 via co-precipitation method is reported. By controlling copper and aluminum (Cu-Al) substituent ratio, the magnetic moment and coercivity of synthesized cobalt ferrite nanoparticles is optimized. The role of substituents on the structure, particle size, morphology, and magnetic properties of nano-crystalline ferrite is investigated. The Co1-xCuxFe2-xAlxO4 (0.0 ≤ x≤ 0.8) nanoparticles with crystallite size in the range of 23.1-26.5 nm are observed, 26.5 nm for x = 0.0-23.1 nm for x = 0.8. The inverse-spinel structure of synthesized Co1-xCuxFe2-xAlxO4 (0.0 ≤ x ≤ 0.8) nano-particles is confirmed by characteristic vibrational bands at tetrahedral and octahedral sites using Fourier transform infrared spectroscopy. A decreases in coercive field and magnetic moment is observed as Cu-Al contents are increased (x = 0.0-0.8). The positive anisotropy of synthesized particles Co1-xCuxFe2-xAlxO4 (0.0 ≤ x ≤ 0.8) is obtained in the range 1.96 × 105 J/m3 for x = 0.0 to 0.29 × 105 J/m3 for x = 0.8.

Role of nickel doping on structural, optical, magnetic properties and antibacterial activity of ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Vijayaprasath, G.; Murugan, R. [School of Physics, Alagappa University, Karaikudi 630 004, Tamil Nadu (India); Palanisamy, S.; Prabhu, N.M. [Department of Animal Health and Management, Alagappa University, Karaikudi 630 004, Tamil Nadu (India); Mahalingam, T. [Department of Electrical and Computer Engineering, Ajou University, Suwon 443-749 (Korea, Republic of); Hayakawa, Y. [Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8011 (Japan); Ravi, G., E-mail: gravicrc@gmail.com [School of Physics, Alagappa University, Karaikudi 630 004, Tamil Nadu (India)

2016-04-15

Highlights: • The XRD analyses revealed that the synthesizes nickel doped ZnO (Zn{sub 1−x}Ni{sub x}O, x = 0.0, 0.03, 0.06 and 0.09) nanostructures have hexagonal wurtzite structure. • The photoluminescence measurements revealed that the broad emission was composed of different bands due to zinc and oxygen vacancies. • X-ray photoelectron spectroscopy (XPS) confirmed the Ni incorporation in ZnO lattice as Ni{sup 2+} ions. • Room temperature ferromagnetism was observed due to the oxygen vacancies and zinc interstitials are the main reasons for ferromagnetism in Ni doped ZnO NPs. - Abstract: Zn{sub 1−x}Ni{sub x}O nanoparticles were synthesized by co-precipitation method. The crystallite sizes of the synthesized samples found to decrease from 38 to 26 nm with increase in nickel concentration. FTIR spectra confirmed the presence of Zn−O stretching bands at 577, 573, 569 and 565 cm{sup −1} in the respective ZnO NPs. Optical absorption spectra revealed the red shifted and estimated band gap is found to decrease with increase of Ni doping concentration. The PL spectra of all the samples exhibited a broad emission at 390 nm in the visible range. The carriers (donors) bounded on the Ni sites were observed from the micro Raman spectroscopic studies. Pure and Ni doped ZnO NPs showed significant changes in the M–H loop, especially the diamagnetic behavior changed into ferromagnetic nature for Ni doped samples. The antiferromagnetic super-exchange interactions between Ni{sup 2+} ions is increased in higher Ni doped ZnO NPs and also their antibacterial activity has been studied.

Microemulsion synthesis and magnetic properties of Fe{sub x}Ni{sub (1−x)} alloy nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Beygi, H., E-mail: hossein.beygi@stu-mail.um.ac.ir; Babakhani, A.

2017-01-01

This paper investigates synthesis of Fe{sub x}Ni{sub (1−x)} bimetallic nanoparticles by microemulsion method. Through studying the mechanism of nanoparticles formation, it is indicated that synthesis of nanoparticles took placed by simultaneous reduction of metal ions and so nanoparticles structure is homogeneous alloy. Fe{sub x}Ni{sub (1−x)} nanoparticles with different sizes, morphologies and compositions were synthesized by changing the microemulsion parameters such as water/surfactant/oil ratio, presence of co-surfactant and NiCl{sub 2}·6H{sub 2}O to FeCl{sub 2}·4H{sub 2}O molar ratio. Synthesized nanoparticles were characterized by transmission electron microscopy, particle size analysis, X-ray diffraction, atomic absorption and thermogravimetric analyses. The results indicated that, presence of butanol as co-surfactant led to chain-like arrangement of nanoparticles. Also, finer nanoparticles were synthesized by decreasing the amount of oil and water and increasing the amount of CTAB. The results of vibrating sample magnetometer suggested that magnetic properties of Fe{sub x}Ni{sub (1−x)} alloy nanoparticles were affected by composition, size and morphology of the particles. Spherical and chain-like Fe{sub x}Ni{sub (1−x)} alloy nanoparticles were superparamagnetic and ferromagnetic, respectively. Furthermore, higher iron in the composition of nanoparticles increases the magnetic properties. - Highlights: • Fe{sub x}Ni{sub (1−x)} alloy NPs synthesized by simultaneous metal ions reduction in microemulsion. • Finer NPs synthesized at lower amount of oil and water and higher amount of CTAB. • Chain-like Fe{sub x}Ni{sub (1−x)} NPs are ferromagnetic; higher aspect ratio, more magnetization. • Spherical Fe{sub x}Ni({sub 1−x)} NPs with smaller size (7 nm) are superparamagnetic. • Spherical Fe{sub x}Ni{sub (1−x)} nanoparticles with higher x had increased magnetic properties.

Study of de-aggregation of mechanochemically synthesized ZnSe nanoparticles by re-milling in the presence of ZnCl2 solution

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Marcela Achimovičová

2013-12-01

Full Text Available Conventional mechanochemical synthesis of zinc selenide, ZnSe nanoparticles was performed in a planetary ball mill by high-energy milling of zinc (Zn and selenium (Se powders. Mechanochemically synthesized ZnSe was subsequently re-milled in circulation mill in ZnCl2 solution in order to study de-aggregation, physical-chemical and optical properties of ZnSe nanoparticles. The mechanochemically synthesized and re-milled samples were characterized by X-ray diffraction analysis (XRD that confirmed the presence of cubic and hexagonal ZnSe phases. Size of crystallites calculated from XRD patterns has decreased from 50 to 19 nm for cubic ZnSe phase and from 145 to 2.5 nm for hexagonal ZnSe phase after re-milling for 110 min in ZnCl2 solution. Size, phase composition, morphology, and crystallinity of ZnSe nanoparticles were studied by transmission electron microscopy (TEM and selected area electron diffraction (SAED. UV-Vis optical spectroscopy has provided an evidence of blue shift of the re-milled nanocrystalline ZnSe particles from the direct band gap of 2.67 eV characteristic of bulk ZnSe crystals. Colloidal stability of ZnSe nanoparticles dispersions was studied by ? �potential measurements.

Structural studies of mechano-chemically synthesized CuIn1-xGaxSe2 nanoparticles

International Nuclear Information System (INIS)

Vidhya, B.; Velumani, S.; Arenas-Alatorre, Jesus A.; Morales-Acevedo, Arturo; Asomoza, R.; Chavez-Carvayar, J.A.

2010-01-01

CuInGaSe 2 is a I-III-VI 2 semiconducting material of tetragonal chalcopyrite structure. It is a very prominent absorber layer for photovoltaic devices. Particle-based coating process for CIGS is considered to be promising technique with relatively simple procedures and low initial investment. In the present work CIGS nanoparticle precursors suitable for screen-printing ink has been prepared by ball milling. High purity elemental copper granules, selenium and indium powders and fine chips of gallium were used as starting materials. First the ball milling was carried out for CuIn 1-x Ga x Se 2 (x = 0.5) with (i) 10 ml of ethyl alcohol (ii) 5 ml of tetra ethylene glycol (wet) and (iii) 1 ml of ethylene diamine (semi-dry) for a milling time of 3 h and the results are not stoichiometric. In order to obtain an improved stoichiometric composition dry ball milling of elemental sources for three different compositions of CuIn 1-x Ga x Se 2 (x = 0.25, 0.5 and 0.75) has been carried out. X-ray diffraction analysis revealed the presence of (1 1 2), (2 2 0)/(2 0 4), (3 1 2)/(1 1 6), (4 0 0) and (3 3 2) reflections for all the milled powders. These reflections correspond to chalcopyrite structure of CIGS. Shift in peaks towards higher value of 2θ is observed with the increase in Ga composition. Average grain size calculated by Scherrer's formula is found to be around 13 nm for the dry samples milled for 1.5 h and 7-8 nm for the samples wet milled for 3 h. Lattice constants 'a' and 'c' are found to decrease with the increase in concentration of Gallium. FESEM analysis revealed a strong agglomeration of the particles and the particle size varied from 11 to 30 nm for the dry-milled samples. Composition of milled powders has been studied by energy dispersive X-ray analysis. TEM analysis revealed the presence of nanocrystalline particles and SAED pattern corresponds to (1 1 2), (2 2 0)/(2 0 4), (5 1 2)/(4 1 7) and (6 2 0)/(6 0 4) diffraction peaks of CIGS. From the HRTEM analysis

Surface properties and dye loading behavior of Zn2SnO4 nanoparticles hydrothermally synthesized using different mineralizers

International Nuclear Information System (INIS)

Annamalai, Alagappan; Eo, Yang Dam; Im, Chan; Lee, Man-Jong

2011-01-01

We present for the first time the influence of different mineralizers on the isoelectric point (IEP) of zinc stannate (Zn 2 SnO 4 ) nanoparticles hydrothermally prepared using three different mineralizers, viz., Na 2 CO 3 , KOH and tert-butyl amine, and the effect of the IEPs on the dye loading behavior of Zn 2 SnO 4 based photoelectrodes in dye sensitized solar cells (DSSCs). To produce highly crystalline, uniform sized Zn 2 SnO 4 nanoparticles, hydrothermal processing parameters, such as reaction temperature, time, and the mineralizers used have been critically adjusted. The structural and morphological features of the as-synthesized Zn 2 SnO 4 nanoparticles have been observed using both scanning and transmission electron microscopy. For the surface state characterization of shape- and size-controlled Zn 2 SnO 4 nanoparticles, the IEPs of Zn 2 SnO 4 surfaces were determined through zeta potential measurements. The IEPs were found to be 5.7, 7.4 and 8.1 for Zn 2 SnO 4 nanoparticles formed using Na 2 CO 3 , KOH and tert-butyl amine, respectively, suggesting that the surface properties of Zn 2 SnO 4 nanoparticles can be manipulated through the choice of the mineralizers used during the hydrothermal reaction. The amount of N719 dye loading on the surfaces of Zn 2 SnO 4 electrodes having different IEPs was also evaluated. It was revealed that the higher the IEP, the higher the dye loading amount, which means that the IEP mainly affects the dye loading at the dye-metal oxide interface. - Highlights: → The effect of various mineralizers on the isoelectric point of Zn 2 SnO 4 was discussed. → The IEP of Zn 2 SnO 4 can be modified by the choice of mineralizer. → Change in IEP affects the surface properties and the morphology of Zn 2 SnO 4 particles. → Modified surface affects the N719 dye loading behaviour of the Zn 2 SnO 4 based DSSCs.

Microstructural characterization of gold nanoparticles synthesized by solution plasma processing

International Nuclear Information System (INIS)

Cho, Sung-Pyo; Bratescu, Maria Antoaneta; Takai, Osamu; Saito, Nagahiro

2011-01-01

Microstructural characteristics of gold nanoparticles (Au NPs) fabricated by solution plasma processing (SPP) in reverse micelle solutions have been studied by high-resolution transmission electron microscopy (HRTEM). The synthesized Au NPs, with an average size of 6.3 ± 1.4 nm, have different crystal characteristics; fcc single-crystalline particles, multiply twinned particles (MTPs), and incomplete MTPs (single-nanotwinned fcc configuration). The crystal structure characteristics of the Au NPs synthesized by the SPP method were analyzed and compared with similar-size Au NPs obtained by the conventional chemical reduction synthesis (CRS) method. The TEM analysis results show that the Au NPs synthesized by the CRS method have shapes and crystal structures similar to those nanoparticles obtained by the SPP method. However, from the detailed HRTEM analysis, the relative number of the Au MTPs and incomplete MTPs to the total number of the Au NPs synthesized by the SPP method was observed to be around 94%, whereas the relative number of these kinds of crystal structures fabricated by the CRS method was about 63%. It is most likely that the enhanced formation of the Au MTPs is due to the fact that the SPP method generates highly reaction-activated species under low environmental temperature conditions.

A study on the effect of chemically synthesized magnetite nanoparticles on earthworm: Eudrilus eugeniae

Science.gov (United States)

Samrot, Antony V.; Justin, C.; Padmanaban, S.; Burman, Ujjala

2017-02-01

Most look into the benefits of the nanoparticles, but keeping aside the benefits; this study focuses on the impacts of nanoparticles on living systems. Improper disposal of nanoparticles into the environment is a subject of pollution or nano-pollution which in turn affects the flora and fauna in the ecosystem, particularly soil ecosystem. Thus, this study was done to understand the impacts of chemically synthesized magnetite nanoparticles on earthworm— Eudrilus eugeniae, a soil-dependent organism which acquires food and nutrition from decaying matters. The chemically synthesized magnetite nanoparticles were characterized by UV-visible spectrophotometry, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Earthworms were allowed to interact with different concentrations of synthesized nanoparticles and the effect of the nanoparticles was analysed by studying the phenotypic changes followed by histology and inductively coupled plasma optical emission spectrometry analyses.

Interaction between serum albumins and sonochemically synthesized cadmium sulphide nanoparticles: a spectroscopic study

International Nuclear Information System (INIS)

Naveenraj, Selvaraj; Asiri, Abdullah M.; Anandan, Sambandam

2013-01-01

Cadmium Sulphide nanoparticles approximately 5–10 nm in size range were synthesized by sonochemical technique, which follows acoustic cavitation phenomenon and generates nanoparticles with a smaller size range and higher surface area. The in vitro binding interaction of these sonochemically synthesized CdS nanoparticles with serum albumins (SA) were investigated using UV–Vis absorption, fluorescence and circular dichroism (CD) spectroscopic techniques since CdS nanoparticles has biological applications such as cellular labelling and deep-tissue imaging. UV–Vis absorption and fluorescence studies confirm that CdS nanoparticles bind with SA through ground state complex formation (static quenching mechanism). The results suggest that sonochemically synthesized CdS nanoparticles interact with HSA more than that of BSA and these nanoparticles can be easily transported and rapidly released to the targets by serum albumins. CD studies confirmed the conformational change of serum albumins on the interaction of CdS nanoparticles.Graphical AbstractThis paper investigates the in vitro binding interaction of Cadmium Sulphide (CdS) nanoparticles with serum albumins (HSA and BSA) using the UV-vis, steady-state fluorescence, time-resolved fluorescence, synchronous fluorescence and circular dichroism (CD) spectral techniques.

Luminescent properties of complexly substituted oxides Ме2Ln8 (XO46O2 (Me=Sr, Ca; Ln=La, Gd, Eu; X= Si, P

Directory of Open Access Journals (Sweden)

A. A. Vasin

2014-11-01

Full Text Available In the current work it is established that the maximum intensity of a luminescence of crystalline phosphors with structure silicate-apatite of general formulae: Ca2Eu8Si6(1-xP6xO26, Sr2Gd7.2Eu0.8Si6(1-xP6xO26 and Ca2La8(1-xEu8xSi6O26 is reached at concentration of europium equal 0,15. The maximum intensity of a luminescence of these substances, at replacement in an anion sublattice of tetrahedrons [SiO4]4- on tetrahedrons [PO4]3- takes place at concentration of phosphorus 0,05.

Optical and electrical properties of Zn{sub 1-x}Cd{sub x}O thin films

Energy Technology Data Exchange (ETDEWEB)

Joishy, Sumanth; Rajendra, B.V. [Manipal University, Department of Physics, Manipal Institute of Technology, Manipal (India)

2017-11-15

This report includes comprehensive studies on the influence of cadmium doping level of structure, surface morphology, optical and electrical properties of synthesized Zn{sub 1-x}Cd{sub x}O thin films by simple and inexpensive spray pyrolysis method under optimized deposition conditions using zinc acetate dihydrate and cadmium acetate dihydrate as precursors. All deposited films were polycrystalline in nature. The deposits were having 20-50% of the Cd content-shown mixture of hexagonal-cubic phases. However, with increasing Cd concentration only cubic phases were observed. The films have a fibrous structure change to the spherical nano-structure when doping level is more than 10% in the deposits. The composition of the Zn{sub x}Cd{sub 1-x}O-deposited films was confirmed by EDAX spectrum. Optical transmittance of deposits in the visible range was decreased with increasing Cd dopant. The change of energy band gap of Cd-doped ZnO films from 3.01 to 2.29 eV was observed. A systematic increase of the films n-type electrical conductivity was noticed due to increasing carrier concentration in the deposits except for 40% of Cd doping. (orig.)

Luminescent and photocatalytic properties of cadmium sulfide nanoparticles synthesized via microwave irradiation

International Nuclear Information System (INIS)

Yang Huaming; Huang Chenghuan; Li Xianwei; Shi Rongrong; Zhang Ke

2005-01-01

Uniform cadmium sulfide (CdS) nanoparticles of about 6 nm in crystal size have been successfully synthesized via microwave irradiation. The as-prepared sample has a uniform morphology and high purity. The red photoluminescence spectrum of the CdS nanoparticles displays a strong peak at 602 nm by using a 300 nm excitation wavelength. The photocatalytic oxidation of methyl orange (MeO) in CdS suspensions under ultraviolet illumination was investigated. The results indicate that a low pH value (pH 2.0) and low reaction temperatures (20-30 deg. C) will facilitate the decolorization of the MeO solution. The photodegradation degree decreases with increasing the pH value and temperature of solution. The efficiency of the recycled CdS semiconductor becomes lower due to the deposit of elemental Cd on the CdS surface, which weakens the photocatalytic activity. The luminescent and photocatalytic mechanisms of the as-prepared CdS nanoparticles were primarily discussed. Microwave irradiation is proved to be a convenient, efficient and environmental-friendly one-step route to synthesize nanoparticles

Characteristics of ceramic oxide nanoparticles synthesized using radio frequency produced thermal plasma

International Nuclear Information System (INIS)

Dhamale, Gayatri D.; Mathe, V.L.; Bhoraskar, S.V.; Ghorui, S.

2015-01-01

Thermal plasma devices with their unique processing capabilities due to extremely high temperature and steep temperature gradient play an important role in synthesis of ultrafine powders in the range of 100nm or less. High temperature gas phase synthesis in Radio Frequency (RF) thermal plasma reactor is an attractive route for mass production of refractory nanoparticles, especially in the case of rare earth oxides. Here we report synthesis of Yttrium Oxide (Y_2O_3), Neodymium Oxide (Nd_2O_3) and Aluminum Oxide (Al_2O_3) in an inductively coupled radio frequency thermal plasma reactor. Synthesized nanoparticles find wide application in various fields like gate dielectrics, photocatalytic applications, laser devices and photonics. Nano sized Yttrium oxide, Neodymium Oxide and Aluminum oxide powders were separately synthesized in an RF plasma reactor starting with micron sized irregular shaped precursor powders. The system was operated at 3MHz in atmospheric pressure at different power levels. Synthesized powders were scrapped out from different deposition locations inside the reactor and characterized for their phase, morphology, particle size, crystallinity and other characteristic features. Highly crystalline nature of the synthesized particles, narrow size distribution, location dependent phase formation, and distinct variation in the inherent defect states compared to the bulk are some of the important characteristic features observed

Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO.sub.2 reforming of methane

KAUST Repository

Biausque, Gregory; Laveille, Paco; Anjum, Dalaver H.; Caps, Valerie; Basset, Jean-Marie

2015-01-01

Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO.sub.2 reforming of methane

Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO.sub.2 reforming of methane

KAUST Repository

Biausque, Gregory

2015-04-28

Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO.sub.2 reforming of methane

Antibacterial Activity Of ternary semiconductor compounds AgInSe2 Nanoparticles Synthesized by Simple Chemical Method

Science.gov (United States)

Shehab, A. A.; Fadaam, S. A.; Abd, A. N.; Mustafa, M. H.

2018-05-01

In this objective AgInSe2Nanoparticles (AgInSe2 NPs) were prepared by a simple chemical method (SCM). The optica structural l and morphological properties of the synthesized AgInSe2 NPs swere investigated by using UVVI absorption atomic force microscopy AFMmf, Fourier Transform Infrared Spectroscopy and x-ray diffraction. The resistance of bacteria represents a trouble and the outlook for the use of antibiotics in the future until now uncertain. Measures must be taken to decrease this problem. Antibacterial activity of the AgInSe2 nanoparticles were exposed against several pathogenic bacteriaa including Klebsiella pneumonia KPa, Staphylococcus aureus, Bacillus subtili, Enterobacter Cloacae and Esherichia Coliby. Using a good spread method the results showed that AgInSe2 NPs had inhibitory effect versus some pathogenic bacteria with suppression area 18, 14 and 17 mm for SAgInSe2 NPs had an inhibitory effect against S Bacillus Subtilis 11 mm K EnterobactercCloacae 12 mm.

Chemical phase analysis of seed mediated synthesized anisotropic silver nanoparticles

International Nuclear Information System (INIS)

Bharti, Amardeep; Goyal, Navdeep; Singh, Suman; Singla, M. L.

2015-01-01

Noble-metal nanoparticles are of great interest because of its broad applications almost in every stream (i.e. biology, chemistry and engineering) due to their unique size/shape dependant properties. In this paper, chemical phase of seed mediated synthesized anisotropic silver nanoparticle (AgNPs) has been investigated via fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). These nanaoparticles were synthesized by seed-growth method controlled by urea and dextrose results to highly stable 12-20 nm particle size revealed by zeta potential and transmission electron microscopy (TEM)

Synthesis and characterization of perovskites type La(Fe_xV_1_-_x)O_3

International Nuclear Information System (INIS)

Tupan, Lilian Felipe da Silva

2014-01-01

Perovskites of the La(Fe_xV_1_-_x)O_3 type were synthesized by solid state reaction and by arc-melting. The samples prepared were structurally characterized by X-ray diffraction and regarding the magnetic and hyperfine properties by "5"7Fe Mössbauer spectroscopy. The results revealed that the samples crystallized mostly with orthorhombic structure, in the Pbnm space group. The lattice parameters of the pseudo-ternary compounds decreased linearly with the progressive substitution of iron by vanadium, in agreement with the Vegard's law. It was also observed the reduction of the hyperfine magnetic field which changes from a well defined sextet of 51,8 T, obtained for LaFeO_3, to a magnetic field distribution and, further, to a paramagnetic component for the richest vanadium samples. Low temperature Mössbauer spectroscopy measurements were additionally performed for the La(Fe_0_,_2V_0_,_8)O_3 sample. It was shown that the sample recovers the magnetic order with decreasing temperature. These results reveal that the coexistence of iron-vanadium results in an even more complicated magnetic behavior, decreasing the magnetic transition temperature, as replacement of iron by vanadium in orthoferrite increases. (author)

Transformation characteristics of LaV/sub x/Nb/sub 1-x/O4 compounds

International Nuclear Information System (INIS)

Nevitt, M.V.; Aldred, A.T.

1983-06-01

X-ray diffractometry measurements were made as a function of temperature on a series of polycrystalline LaV/sub x/Nb/sub 1-x/O 4 compounds (0 4 compounds that are either candidates or are appropriate models for candidate materials for hosting nuclear-waste ions. Partial substitution of V 5+ on the Nb 5+ site significantly lowers the tetragonal scheelite (I4 1 /a) to monoclinic fergusonite (I2/c) transformation, from 770 0 K in LaNbO 4 to approximately 215 0 K for LaV 0 25 Nb 0 75 O 4 (the solubility limit is close to x = 0.35). The transformation is displacive, of second order, involving two coupled order parameters. Heat capacity measurements on LaV 0 25 Nb 0 75 O 4 showed that the specific heat anamoly at the transformation point is extremely small. It is concluded that the two polymorphic forms of LaV/sub x/Nb/sub 1-x/O 4 have very nearly the same free energies over a substantial range of temperature below the transformation

Sterilization of African Violet in the in Vitro Culture Using Synthesized Silver Nanoparticles by Two Plant Extracts

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M. Solgi

2015-12-01

Full Text Available One of the major advantages of in vitro culture of African violet (Saintpaulha ionantha is production of new cultivars and propagation of their chimera which might not be propagated by the other methods. In this study, we tested the effects of silver nanoparticles on the sterilization rate (antifungal and antibacterial activity, regeneration and shoot formation of African violet "Pink Amiss" explants. These nanoparticles were synthesized from pomegranate peels and Damask rose petals extracts. We used a completely randomized design test with factorial arrangement to investigate various volumetric ratios of plant extracts to silver nitrate (1:20, 1:10, 1:5 and 1:1 on the culture contaminations. Using silver nanoparticles synthesized by the plant extracts, especially Damask rose petals extract resulted in no fungal and bacterial contamination in the African violet explants after 1 and 3 weeks as compared to the control, and silver nitrate (1mM. All tested concentrations of the silver nanoparticles significantly (P &le 0.05 controlled both bacterial and fungal contaminations. The 1:20 ratio of plant extracts to silver nitrate showed the best control. In addition, the highest regeneration (%52 and shoot regeneration (%38 was observed in this treatment. In conclusion, we suggest using silver nanoparticles synthesized by plant extracts for sterilization of in Vitro Culture for African Violet rather than using other chemicals such as silver nitrate.

New process of preparation, X-ray characterisation, structure and vibrational studies of a solid solution LiTiOAs 1-xP xO 4 (0⩽ x⩽1)

Science.gov (United States)

Chakir, M.; El Jazouli, A.; Chaminade, J. P.; Bouree, F.; de Waal, D.

2006-01-01

LiTiOAs 1-xP xO 4 (0⩽ x⩽1) compounds have been prepared using solutions of Li, Ti, As and P elements as starting products. Selected compositions have been investigated by powder X-ray or neutrons diffraction analysis, Raman and infrared spectroscopy. The structure of LiTiOAs 1-xP xO 4 ( x=0, 0.5 and 1) samples determined by Rietveld analysis is orthorhombic with Pnma space group. It is formed by a 3D network of TiO 6 octahedra and XO 4 ( X=As 1-xP x) tetrahedra where octahedral cavities are occupied by lithium atoms. TiO 6 octahedra are linked together by corners and form infinite chains along a-axis. Ti atoms are displaced from the centre of octahedral units in alternating short (1.700-1.709 Å) and long (2.301-2.275 Å) Ti-O bonds. Raman and infrared studies confirm the existence of Ti-O-Ti chains. Thermal stability of LiTiOAsO 4 has been reported.

A Study On Dispersion Stability Of Nickel Nanoparticles Synthesized By Wire Explosion In Liquid Media

OpenAIRE

Kim C.K.; Lee G.-J.; Lee M.K.; Rhee C.K.

2015-01-01

In this study, nickel nanoparticles were synthesized in ethanol using portable pulsed wire evaporation, which is a one-step physical method. From transmission electron microscopy images, it was found that the Ni nanoparticles exhibited a spherical shape with an average diameter of 7.3 nm. To prevent aggregation of the nickel nanoparticles, a polymer surfactant was added into the ethanol before the synthesis of nickel nanoparticles, and adsorbed on the freshly synthesized nickel nanoparticles ...

Characterization of chemically synthesized CdS nanoparticles

Indian Academy of Sciences (India)

Similar to the effects of charge carriers on optical properties, confinement of optical and acoustic phonons leads to interesting changes in the phonon spectra. In the present work, we have synthesized nanoparticles of CdS using chemical precipitation technique. The crystal structure and grain size of the particles are studied ...

Facile synthesis of ferromagnetic Ni doped CeO{sub 2} nanoparticles with enhanced anticancer activity

Energy Technology Data Exchange (ETDEWEB)

Abbas, Fazal; Jan, Tariq [Laboratory of Nanoscience and Technology, Department of Physics, International Islamic University Islamabad (Pakistan); Iqbal, Javed, E-mail: javed.saggu@iiu.edu.pk [Laboratory of Nanoscience and Technology, Department of Physics, International Islamic University Islamabad (Pakistan); Ahmad, Ishaq [Experimental Physics Labs, National Center for Physics, Islamabad (Pakistan); Naqvi, M. Sajjad H. [Department of Biochemistry, University of Karachi, Karachi (Pakistan); Malik, Maaza [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa)

2015-12-01

Highlights: • The synthesized undoped and Ni doped CeO{sub 2} nanoparticles exhibited RTFM. • Oxygen vacancies and magnetic ions both were believed to be responsible for RTFM. • The prepared nanoparticles exhibited selective cytotoxicity. • Ni doping enhanced the anticancer activity of CeO{sub 2} nanoparticles. • Differential ROS generation was observed to control their cytotoxicity. - Abstract: Ni{sub x}Ce{sub 1−x}O{sub 2} (where x = 0, 0.01, 0.03, 0.05 and 0.07) nanoparticles were synthesized by soft chemical method and were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, UV–vis absorption spectroscopy and vibrating sample magnetometer (VSM). XRD and Raman results indicated the formation of single phase cubic fluorite structure for the synthesized nanoparticles. Ni dopant induced excessive structural changes such as decrease in crystallite size as well as lattice constants and enhancement in oxygen vacancies in CeO{sub 2} crystal structure. These structural variations significantly influenced the optical and magnetic properties of CeO{sub 2} nanoparticles. The synthesized Ni{sub x}Ce{sub 1−x}O{sub 2} nanoparticles exhibited room temperature ferromagnetic behavior. Ni doping induced effects on the cytotoxicity of CeO{sub 2} nanoparticles were examined against HEK-293 healthy cell line and SH-SY5Y neuroblastoma cancer cell line. The prepared Ni{sub x}Ce{sub 1−x}O{sub 2} nanoparticles demonstrated differential cytotoxicity. Furthermore, anticancer activity of CeO{sub 2} nanoparticles observed to be significantly enhanced with Ni doping which was found to be strongly correlated with the level of reactive oxygen species (ROS) production. The prepared ferromagnetic Ni{sub x}Ce{sub 1−x}O{sub 2} nanoparticles with differential cytotoxic nature may be potential for future targeted cancer therapy.

Low Temperature Synthesis, Chemical and Electrochemical Characterization of LiNi(x)Co(1-x)O2 (0 less than x less than 1)

Science.gov (United States)

Nanjundaswamy, K. S.; Standlee, D.; Kelly, C. O.; Whiteley, R. V., Jr.

1997-01-01

A new method of synthesis for the solid solution cathode materials LiNi(x)Co(1-x)O2 (0 less than x less than 1) involving enhanced reactions at temperatures less than or equal to 700 deg. C, between metal oxy-hydroxide precursors MOOH (M = Ni, Co) and Li-salts (Li2CO3, LiOH, and LiNO3) has been investigated. The effects of synthesis conditions and sources of Li, on phase purity, microstructure, and theoretical electrochemical capacity (total M(3+) content) are characterized by powder X-ray diffraction analysis, scanning electron microscopy, chemical analysis and room temperature magnetic susceptibility. An attempt has been made to correlate the electrochemical properties with the synthesis conditions and microstructure.

Gd doping induced weak ferromagnetic ordering in ZnS nanoparticles synthesized by low temperature co-precipitation technique

Energy Technology Data Exchange (ETDEWEB)

Kaur, Palvinder [Department of Physics, Punjabi University, Patiala, Punjab, 147002 (India); Kumar, Sanjeev, E-mail: sanjeev04101977@gmail.com [Applied Science Department, PEC University of Technology, Chandigarh, 160012 (India); Chen, Chi-Liang, E-mail: chen.cl@nsrrc.org.tw [National Synchrotron Radiation Research Center (NSRRC), Hsinchu, 30076, Taiwan (China); Yang, Kai-Siang [National Synchrotron Radiation Research Center (NSRRC), Hsinchu, 30076, Taiwan (China); Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan (China); Wei, Da-Hua [Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan (China); Dong, Chung-Li [Department of Physics, Tamkang University, Tamsui, Taiwan (China); Srivastava, C. [Materials Engineering Department, Indian Institute of Science, Bangalore, 560012 (India); Rao, S.M. [Department of Physics, Punjabi University, Patiala, Punjab, 147002 (India); Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan (China)

2017-01-15

Zn{sub 1−x}Gd{sub x}S nanoparticles with Gd concentration x = 0.00, 0.02 and 0.04 were synthesized by the chemical co-precipitation technique using thioglycerol as capping agent. X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy, X-ray absorption near-edge structure (XANES) and vibrating sample magnetometer (VSM) were employed to characterize the as synthesized Gd doped ZnS nanoparticles. XRD and TEM studies show the formation of cubic ZnS nanoparticles with an average size in the range 5–10 nm. The doping did not alter the phase of the ZnS. The PL spectra of doped ZnS nanoparticles showed the presence of sulphur vacancies in the lattice. XANES of Gd doped ZnS nanoparticles depicts spectral changes may arise from charge transfer between host Zn and dopant Gd ions. A VSM study shows that the weak ferromagnetic behaviour increases with increase in Gd doping ZnS nanoparticles. - Highlights: • Gd doped ZnS nanoparticles synthesized using co-precipitation technique. • PL studies depict sulphur and zinc vacancies in Gd doped ZnS nanoparticles. • XANES studies depict the charge transfer between host Zn and dopant Gd ions. • Room temperature weak ferromagnetism is observed in Gd doped ZnS nanoparticles.

Gd doping induced weak ferromagnetic ordering in ZnS nanoparticles synthesized by low temperature co-precipitation technique

International Nuclear Information System (INIS)

Kaur, Palvinder; Kumar, Sanjeev; Chen, Chi-Liang; Yang, Kai-Siang; Wei, Da-Hua; Dong, Chung-Li; Srivastava, C.; Rao, S.M.

2017-01-01

Zn_1_−_xGd_xS nanoparticles with Gd concentration x = 0.00, 0.02 and 0.04 were synthesized by the chemical co-precipitation technique using thioglycerol as capping agent. X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy, X-ray absorption near-edge structure (XANES) and vibrating sample magnetometer (VSM) were employed to characterize the as synthesized Gd doped ZnS nanoparticles. XRD and TEM studies show the formation of cubic ZnS nanoparticles with an average size in the range 5–10 nm. The doping did not alter the phase of the ZnS. The PL spectra of doped ZnS nanoparticles showed the presence of sulphur vacancies in the lattice. XANES of Gd doped ZnS nanoparticles depicts spectral changes may arise from charge transfer between host Zn and dopant Gd ions. A VSM study shows that the weak ferromagnetic behaviour increases with increase in Gd doping ZnS nanoparticles. - Highlights: • Gd doped ZnS nanoparticles synthesized using co-precipitation technique. • PL studies depict sulphur and zinc vacancies in Gd doped ZnS nanoparticles. • XANES studies depict the charge transfer between host Zn and dopant Gd ions. • Room temperature weak ferromagnetism is observed in Gd doped ZnS nanoparticles.

Evaluation of tetraethoxysilane (TEOS) sol–gel coatings, modified with green synthesized zinc oxide nanoparticles for combating microfouling

Energy Technology Data Exchange (ETDEWEB)

Krupa, A. Nithya Deva; Vimala, R., E-mail: vimala.r@vit.ac.in

2016-04-01

Green synthesis of zinc oxide nanoparticles (ZnO-NPs) is gaining importance as an eco-friendly alternative to conventional methods due to its enormous applications. The present work reports the synthesis of ZnO-NPs using the endosperm of Cocos nucifera (coconut water) and the bio-molecules responsible for nanoparticle formation have been identified. The synthesized nanoparticles were characterized using UV–Visible spectroscopy (UV–Vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Zeta potential measurement. The results obtained reveal that the synthesized nanoparticles are moderately stable with the size ranging from 20 to 80 nm. The bactericidal effect of the nanoparticles was proved by well diffusion assay and determination of minimum inhibitory concentration (MIC) against marine biofilm forming bacteria. Further the green synthesized ZnO-NPs were doped with TEOS sol–gels (TESGs) in order to assess their antimicrofouling capability. Different volumes of liquid sol–gels were coated on to 96-well microtitre plate and cured under various conditions. The optimum curing conditions were found to be temperature 60 °C, time 72 h and volume 200 μl. Antiadhesion test of the undoped (SG) and ZnO-NP doped TEOS sol–gel (ZNSG) coatings were evaluated using marine biofilm forming bacteria. ZNSG coatings exhibited highest biofilm inhibition (89.2%) represented by lowest OD value against Pseudomonasotitidis strain NV1. - Highlights: • The study reports low cost, and simple procedure for the synthesis of ZnO-NPs using coconut water. • XRD result shows the high crystalline nature of the synthesized ZnO-NPs. • TEM and zeta potential distribution confirms the nanostructure, stability of the synthesized ZnO-NPs. • ZnO-NPs doped with TEOS sol¬-gels (TESGs) exhibited excellent antimicrofouling activity.

SWAXS investigations on diffuse boundary nanostructures of metallic nanoparticles synthesized by electrical discharges

Energy Technology Data Exchange (ETDEWEB)

Guo, Xiaoai, E-mail: xiaoai.guo@kit.edu; Gutsche, Alexander; Nirschl, Hermann [Karlsruhe Institute of Technology, Institute for Mechanical Process Engineering and Mechanics (Germany)

2013-11-15

Metallic nanoparticles have attracted a particular interest in scientific research and industrial applications due to their unique size-dependent physical and chemical properties. An eco-friendly and cost-effective synthesis method called electrical discharge enables large scale production of metallic nanoparticles. Systematic investigations of such synthesized metallic nanoparticles help to optimize the synthesis process and improve the product quality. In this work, for the first time we have investigated the diffuse interfacial boundary nanostructures of the metallic nanoparticles, which were synthesized under different conditions by electrical glow and arc discharges in the carrier gas, by means of a small- and wide-angle X-ray scattering (SWAXS) technique using a laboratory X-ray source. Meanwhile, this unique SWAXS technique allows simultaneous study of the primary particle size, morphology, and crystallinity. The metallic nanoparticles (copper and nickel) under investigation cover a size range of 10–80 nm, and the determined thickness of the diffuse boundary nanostructured layer of metallic nanoparticles is in the range of 1–3 nm. The experimental results obtained by SWAXS were compared to the TEM/EDX observation and the XRD reference patterns from RRUFF database, and a good agreement was found. Our SWAXS investigations indicated that the existence of a diffuse nanostructured solid layer on the synthesized metallic nanoparticle surface causes a negative deviation of the scattering intensity (Ι∝q{sup -α}, α>4) from Porod’s law which corresponds to the case of ideal two-phase particle systems with sharp boundaries (Ι∝q{sup -α}, α=4) . This implies that the electron density profile is not sharp but changes gradually between two phases, and hence the exponent α is greater than four. Two electron density profile models, sigmoidal electron-density gradient model and linear electron-density gradient model, have been taken into account in

Effect of zinc concentration on the structural and magnetic properties of mixed Co–Zn ferrites nanoparticles synthesized by sol/gel method

Energy Technology Data Exchange (ETDEWEB)

Ben Ali, M., E-mail: m.benali06@gmail.com [MAScIR Foundation, Institute of Nanomaterials and Nanotechnologies, Materials & Nanomaterials Center, B.P., 10100 Rabat (Morocco); Laboratory of Magnetism and the Physics of the high Energies, URAC 12, Department of Physics, B.P. 1014, Faculty of Science, Mohammed V University, Rabat (Morocco); El Maalam, K. [MAScIR Foundation, Institute of Nanomaterials and Nanotechnologies, Materials & Nanomaterials Center, B.P., 10100 Rabat (Morocco); Laboratory of Magnetism and the Physics of the high Energies, URAC 12, Department of Physics, B.P. 1014, Faculty of Science, Mohammed V University, Rabat (Morocco); El Moussaoui, H.; Mounkachi, O. [MAScIR Foundation, Institute of Nanomaterials and Nanotechnologies, Materials & Nanomaterials Center, B.P., 10100 Rabat (Morocco); Hamedoun, M., E-mail: m.hamedoun@mascir.com [MAScIR Foundation, Institute of Nanomaterials and Nanotechnologies, Materials & Nanomaterials Center, B.P., 10100 Rabat (Morocco); Masrour, R. [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, PB 63 46000, Safi (Morocco); Hlil, E.K. [Institut Néel, CNRS-UJF, B.P. 166, 38042 Grenoble Cedex (France); Benyoussef, A. [MAScIR Foundation, Institute of Nanomaterials and Nanotechnologies, Materials & Nanomaterials Center, B.P., 10100 Rabat (Morocco); Laboratory of Magnetism and the Physics of the high Energies, URAC 12, Department of Physics, B.P. 1014, Faculty of Science, Mohammed V University, Rabat (Morocco)

2016-01-15

Synthesization of zinc-substituted cobalt ferrites nano-particles Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0.0–0.3) has been achieved by the sol/gel method. The characterization of the synthesized nano-particles has been done by X-ray diffractometry (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FITR). The relation between the composition and magnetic properties has been investigated by Magnetic Properties Measurement System (MPMS). The results revealed that the nanoparticles size is in the range of 11–28 nm. It was found that the zinc substitution in cobalt ferrite increases saturation magnetization from 60.92 emu/g (x=0) to 74.67 emu/g (x=0.3). Nevertheless, zinc concentrations cause a significant decrease in coercivity.▪ - Highlights: • The nanocrystals size of synthesized of Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} is of 11–28 nm. • The zinc substitution in cobalt ferrite increase saturation magnetization. • The increase of zinc concentration causes a significant decrease in coercivity.

Ni doped Fe3O4 magnetic nanoparticles.

Science.gov (United States)

Larumbe, S; Gómez-Polo, C; Pérez-Landazábal, J I; García-Prieto, A; Alonso, J; Fdez-Gubieda, M L; Cordero, D; Gómez, J

2012-03-01

In this work, the effect of nickel doping on the structural and magnetic properties of Fe3O4 nanoparticles is analysed. Ni(x)Fe(3-x)O4 nanoparticles (x = 0, 0.04, 0.06 and 0.11) were obtained by chemical co-precipitation method, starting from a mixture of FeCl2 x 4H2O and Ni(AcO)2 x 4H2O salts. The analysis of the structure and composition of the synthesized nanoparticles confirms their nanometer size (main sizes around 10 nm) and the inclusion of the Ni atoms in the characteristic spinel structure of the magnetite Fe3O4 phase. In order to characterize in detail the structure of the samples, X-ray absorption (XANES) measurements were performed on the Ni and Fe K-edges. The results indicate the oxidation of the Ni atoms to the 2+ state and the location of the Ni2+ cations in the Fe2+ octahedral sites. With respect to the magnetic properties, the samples display the characteristic superparamagnetic behaviour, with anhysteretic magnetic response at room temperature. The estimated magnetic moment confirms the partial substitution of the Fe2+ cations by Ni2+ atoms in the octahedral sites of the spinel structure.

Effect of Manganese Addition on the Structure, Magnetic Properties and Microwave Absorption of La0.8Ba0.2MnxFe½(1-x)Ti½(1-x)O3

Science.gov (United States)

Adi, W. A.; Indro, M. N.; Kusumastuti, A. A.

2017-03-01

We have carried out modification of La0.8Ba0.2MnxFe½(1-x)Ti½(1-x)O3 (x = 0.1 - 0.8) magnetic materials by wet milling method. Raw materials of La2O3, BaCO3, Fe2O3, TiO2 and MnCO3 were mixed according to stoichiometry calculation for each composition. The mixture was milled for 5 hours and then sintered at 1000 °C for 5 hours. The refinement results by X-ray diffraction pattern shows that the increasing Mn composition enhances the mass fraction of La0.8Ba0.2MnxFe½(1-x)Ti½(1-x)O3 phase which has the same structure as LaMnO3. For x = 0.8 a single phase of LaMnO3 was formed. The single phase has a crystal monoclinic crystal structure with space group of I 1 2 / a 1, with lattice parameters given by a = 5.519(5) Å, b = 5.5537(5) Å and c = 7.8176(9) Å, α = γ = 90o and β = 90.345(6)o, V = 239.64(3) Å3, ρ = 6.463 gr.cm-3, wRp = 5.96, and χ2 (chi-squared) = 1.17. The hysteresis curve shows that the sample with composition x = 0.8 produces ferromagnetic behaviour at room temperature. The ferromagnetic properties arise due to the mixed valence of Mn3+ and Mn4+ ions through a double exchange mechanism. The results of the microwave absorption indicated that there was a broadening of absorption peak frequency at 9.9 GHz. The reflection loss (RL) increases with the increasing of LaMnO3 phase. For x = 0.8 we have the best of RL where the microwave absorption was calculated reaching 95% at the highest peak frequency with a thickness of 1.5 mm. Thus we have been successful in creating a single phase of La0.8Ba0.2MnxFe½(1-x)Ti½(1-x)O3 with application as a microwave absorber.

Room temperature ferromagnetism in Mn-doped NiO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Layek, Samar, E-mail: samarlayek@gmail.com; Verma, H.C.

2016-01-01

Mn-doped NiO nanoparticles of the series Ni{sub 1−x}Mn{sub x}O (x=0.00, 0.02, 0.04 and 0.06) are successfully synthesized using a low temperature hydrothermal method. Samples up to 6% Mn-doping are single phase in nature as observed from powder x-ray diffraction (XRD) studies. Rietveld refinement of the XRD data shows that all the single phase samples crystallize in the NaCl like fcc structure with space group Fm-3m. Unit cell volume decreases with increasing Mn-doping. Pure NiO nanoparticles show weak ferromagnetism, may be due to nanosize nature. Introduction of Mn within NiO lattice improves the magnetic properties significantly. Room temperature ferromagnetism is found in all the doped samples whereas the magnetization is highest for 2% Mn-doping and then decreases with further doping. The ZFC and FC branches in the temperature dependent magnetization separate well above 350 K indicating transition temperature well above room temperature for 2% Mn-doped NiO Nanoparticle. The ferromagnetic Curie temperature is found to be 653 K for the same sample as measured by temperature dependent magnetization study using vibrating sample magnetometer (VSM) in high vacuum. - Highlights: • Mn-doped NiO nanoparticles are prepared by a simple hydrothermal method. • Unit cell volume decreases with increasing doping concentration. • Mn-doping leads to room temperature ferromagnetism in NiO nanoparticles. • Magnetization is highest for 2% Mn-doping. • Above 2%, magnetization decreases with increasing doping.

Structural and optical studies of Mg doped nanoparticles of chromium oxide (Cr2O3) synthesized by co-precipitation method

Science.gov (United States)

Singh, Jarnail; Verma, Vikram; Kumar, Ravi

2018-04-01

We present here the synthesization, structural and optical studies of Mg doped nanoparticles of Chromium oxide (Cr2O3) prepared using co-precipitation method. These samples were characterized using powder X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Raman spectroscopy and UV-Vis spectroscopy techniques. We have demonstrated that there is negligible change in optical band gap with the Mg doping. The prepared Cr2O3 nanoparticles are spherical in shape, but they are transformed into platelets when doped with Mg. The XRD studies reveal that the Mg doping in Cr2O3 doesn't affect the structure of Chromium oxide (Cr2O3).

Optical properties of cerium oxide (CeO2) nanoparticles synthesized by hydroxide mediated method

Science.gov (United States)

Ali, Mawlood Maajal; Mahdi, Hadeel Salih; Parveen, Azra; Azam, Ameer

2018-05-01

The nanoparticles of cerium oxide have been successfully synthesized by hydroxide mediated method, using cerium nitrate and sodium hydroxide as precursors. The microstructural properties were analyzed by X-ray diffraction technique (XRD). The X-ray diffraction results show that the cerium oxide nanoparticles were in cubic structure. The optical absorption spectra of cerium oxide were recorded by UV-VIS spectrophotometer in the range of 320 to 600 nm and photoluminescence spectra in the range of 400-540 nm and have been presented. The energy band gap was determined by Tauc relationship. The crystallite size was determined from Debye-Scherer equation and came out to be 6.4 nm.

Electrochemical Hydrogen Storage in Facile Synthesized Co@N-Doped Carbon Nanoparticle Composites.

Science.gov (United States)

Zhou, Lina; Qu, Xiaosheng; Zheng, Dong; Tang, Haolin; Liu, Dan; Qu, Deyang; Xie, ZhiZhong; Li, Junsheng; Qu, Deyu

2017-11-29

A Co@nitrogen-doped carbon nanoparticle composite was synthesized via a facile molecular self-assembling procedure. The material was used as the host for the electrochemical storage of hydrogen. The hydrogen storage capacity of the material was over 300 mAh g -1 at a rate of 100 mAg -1 . It also exhibited superior stability for storage of hydrogen, high rate capability, and good cyclic life. Hybridizing metallic cobalt nanoparticle with nitrogen-doped mesoporous carbon is found to be a good approach for the electrochemical storage of hydrogen.

Crystal structure of superparamagnetic Mg0.2Ca0.8Fe2O4 nanoparticles synthesized by sol–gel method

International Nuclear Information System (INIS)

Escamilla-Pérez, A.M.; Cortés-Hernández, D.A.; Almanza-Robles, J.M.; Mantovani, D.; Chevallier, P.

2015-01-01

Powders of magnetic iron oxide nanoparticles (Mg 0.2 Ca 0.8 Fe 2 O 4 ) were prepared by a sol–gel method using ethylene glycol and nitrates of Fe, Ca and Mg as starting materials. Those powders were heat treated at different temperatures (573, 673, 773 and 873 K). In order to evaluate the effect of the heat treatment temperature on the nanoferrites properties, X-ray diffraction (XRD), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques were used. It was found that the reaction products exhibit nanometric sizes and superparamagnetic behavior. It is also demonstrated that, as the heat treatment temperature increases, the particle size and the saturation magnetization of the nanoferrites are increased. - Highlights: • Mg 0.2 Ca 0.8 Fe 2 O 4 superparamagnetic nanoparticles were successfully synthesized. • Particle average sizes of Ca–Mg ferrites were within the range of 8–25 nm. • The nanoferrite treated at 873 K showed a stoichiometry close to Mg 0.2 Ca 0.8 Fe 2 O 4 . • The heat treatment temperature has a strong effect on the crystal structure. • These nanoparticles are potential materials for magnetic hyperthermia

Antibacterial potential of silver nanoparticle synthesized by marine ...

African Journals Online (AJOL)

Multi resistance to antibiotics is a serious and disseminated clinical problem, common to several new compounds that block the resistance mechanism. The present study aimed at the comparative study of silver nanoparticles synthesized through actinomycetes and their antimicrobial metabolites with standard antibiotic.

Magnetic properties of Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} spinel ferrite nanoparticles synthesized by starch-assisted sol–gel autocombustion method and its ball milling

Energy Technology Data Exchange (ETDEWEB)

Yadav, Raghvendra Singh, E-mail: yadav@fch.vutbr.cz [Materials Research Centre, Brno University of Technology, Purkyňova 464/118, 61200 Brno (Czech Republic); Havlica, Jaromir [Materials Research Centre, Brno University of Technology, Purkyňova 464/118, 61200 Brno (Czech Republic); Hnatko, Miroslav; Šajgalík, Pavol [Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 36 Bratislava (Slovakia); Alexander, Cigáň [Institute of Measurement Science, Slovak Academy of Sciences, Dúbravská cesta 9, SK-841 04 Bratislava (Slovakia); Palou, Martin; Bartoníčková, Eva; Boháč, Martin; Frajkorová, Františka; Masilko, Jiri; Zmrzlý, Martin; Kalina, Lukas; Hajdúchová, Miroslava; Enev, Vojtěch [Materials Research Centre, Brno University of Technology, Purkyňova 464/118, 61200 Brno (Czech Republic)

2015-03-15

In this article, Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0.0 and 0.5) spinel ferrite nanoparticles were achieved at 800 °C by starch-assisted sol–gel autocombustion method. To further reduce the particle size, these synthesized ferrite nanoparticles were ball-milled for 2 h. X-ray diffraction patterns demonstrated single phase formation of Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0.0 and 0.5) spinel ferrite nanoparticles. FE-SEM analysis indicated the nanosized spherical particles formation with spherical morphology. The change in Raman modes and relative intensity were observed due to ball milling and consequently decrease of particle size and cationic redistribution. An X-ray Photoelectron Spectroscopy (XPS) result indicated that Co{sup 2+}, Zn{sup 2+} and Fe{sup 3+} exist in octahedral and tetrahedral sites. The cationic redistribution of Zn{sup 2+} and consequently Fe{sup 3+} occurred between octahedral and tetrahedral sites after ball-milling. The change in saturation magnetization (M{sub s}) and coercivity (H{sub c}) with decrease of nanocrystalline size and distribution of cations in spinel ferrite were observed. - Highlights: • Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} spinel ferrite nanoparticles. • Starch-assisted sol–gel auto-combustion method. • Effect of ball-milling on particle size and cation distribution. • Magnetic property dependent on cations and particle size.

Copper nanoparticles synthesized in polymers by ion implantation

DEFF Research Database (Denmark)

Popok, Vladimir; Nuzhdin, Vladimir; Valeev, Valerij

2015-01-01

nanoparticles are observed to partly tower above the sample surface due to a side effect of high-fluence irradiation leading to considerable sputtering of polymers. Implantation and particle formation significantly change optical properties of both polymers reducing transmittance in the UV-visible range due...... as optical transmission spectroscopy. It is found that copper nanoparticles nucleation and growth are strongly fluence dependent as well as they are affected by the polymer properties, in particular, by radiation stability yielding different nanostructures for the implanted PI and PMMA. Shallow synthesized...

Cytotoxicity and antimicrobial activities of green synthesized silver nanoparticles.

Science.gov (United States)

Lokina, S; Stephen, A; Kaviyarasan, V; Arulvasu, C; Narayanan, V

2014-04-09

Bio-inspired silver nanoparticles are synthesized using Malus domestica (apple) extract. Polyphenols present in the apple extract act as a reducing and capping agent to produce the silver nanoparticles. UV-Visible analysis shows the surface plasmon resonance (SPR) absorption at 420 nm. The FTIR analysis was used to identify the functional groups responsible for the bio-reduction of silver ion. The XRD and HRTEM images confirm the formation of silver nanoparticles. The minimal inhibitory concentration (MIC) of silver nanoparticles was recorded against most of the bacteria and fungus. Further, MCF-7 human breast adenocarcinoma cancer cell line was employed to observe the efficacy of cancer cell killing. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Copper-indium-gallium-diselenide nanoparticles synthesized by a solvothermal method for solar cell application

Directory of Open Access Journals (Sweden)

Chiou Chuan-Sheng

2017-01-01

Full Text Available Chalcopyrite copper-indium-gallium-diselenide (CIGS nanoparticles are useful for photovoltaic applications. In this study, the synthesis of CIGS powder was examined, and the powder was successfully synthesized using a relatively simple and convenient elemental solvothermal route. From the reactions of elemental Cu, In, Se and Ga(NO33 powders in an autoclave with ethylenediamine as a solvent, spherical CIGS nanoparticles, with diameters ranging from 20-40 nm, were obtained using a temperature of 200°C for 36h. The structure, morphology, chemical composition and optical properties of the as-synthesized CIGS were characterized using X-ray diffraction, transmission electron microscopy, selected area electron diffraction, scanning electron microscopy, inductively coupled plasma-mass spectrometry. In this sample, the mole ratio of Cu:In:Ga:Se was equal to 0.89:0.71:0.29:2.01, and the optical band gap was found to be 1.18 eV. The solar cell obtained a power conversion efficiency of 5.62% under standard air mass 1.5 global illumination.

Spin canting and magnetic transition in NixZn1-xFe2O4 (x=0.0, 0.5 and 1.0) nanoparticles

Science.gov (United States)

Rani, Stuti; Raghav, Dharmendra Singh; Yadav, Prashant; Varma, G. D.

2018-04-01

Nanoparticles of NixZn1-xFe2O4(x=0.0, 0.5 and 1.0) have been synthesized via co-precipitation method and studied thestructural and magnetic properties. Rietveld refinement of X ray diffraction data of as synthesized samples revealthat the samples have mixed spinel structure with space group Fd-3m. The lattice parameter of the samples decreases as doping concentration of Ni ions increases. Magnetic measurements show paramagnetic to ferrimagnetic transition at room temperature on Ni doping in ZnFe2O4 nanoparticles. The magnetic measurements also show spin canting in samples possibly due to their nanocrystalline nature. The spin canting angles have been calculated with the help of Yafet-Kittel (Y-K) model. Furthermore, the Law of approach (LA) fitting of M-H curves indicates that the samples are highly anisotropicin nature. The Arrot plots of as synthesized samples also indicate the paramagnetic to ferrimagnetic transition. The correlation between the structural and observed magnetic properties of NixZn1-xFe2O4(x=0.0, 0.5 and 1.0) nanocrystals will be described and discussed in this paper.

Seeded Growth of Ferrite Nanoparticles from Mn oxides : Observation of Anomalies in Magnetic Transitions

KAUST Repository

Song, Hyon-Min

2015-06-17

A series of magnetically active ferrite nanoparticles (NPs) are prepared by using Mn oxide NPs as seeds. Verwey transition is identified in Fe3O4 NPs with an average diameter of 14.5 nm at 96 K, where a sharp drop of magnetic susceptibility occurs. In MnFe2O4 NPs, spin glass-like state is observed with the decrease of magnetization below the blocking temperature due to the disordered spins during the freezing process. From these MnFe2O4 NPs, MnFe2O4@MnxFe1-xO core-shell NPs are prepared by seeded growth. The structure of core is cubic spinels (Fd-3m), and shell is composed of iron-manganese oxide (MnxFe1-xO) with a rock salt structure (Fm-3m). Moiré fringes appear perpendicular to <110> directions on the cubic shape NPs through the plane-matched epitaxial growth. These fringes are due to the difference in their lattice spacings between MnFe2O4 and MnxFe1-xO. Exchange bias is observed in these MnFe2O4@MnxFe1-xO core-shell NPs with an enhanced coercivity as well as the shift of hysteresis along the field direction.

Dual-mode T_1 and T_2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application

International Nuclear Information System (INIS)

Tegafaw, Tirusew; Xu, Wenlong; Ahmad, Md Wasi; Lee, Gang Ho; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong

2015-01-01

A new type of dual-mode T_1 and T_2 magnetic resonance imaging (MRI) contrast agent based on mixed lanthanide oxide nanoparticles was synthesized. Gd"3"+ ("8S_7_/_2) plays an important role in T_1 MRI contrast agents because of its large electron spin magnetic moment resulting from its seven unpaired 4f-electrons, and Dy"3"+ ("6H_1_5_/_2) has the potential to be used in T_2 MRI contrast agents because of its very large total electron magnetic moment: among lanthanide oxide nanoparticles, Dy_2O_3 nanoparticles have the largest magnetic moments at room temperature. Using these properties of Gd"3"+ and Dy"3"+ and their oxide nanoparticles, ultrasmall mixed gadolinium-dysprosium oxide (GDO) nanoparticles were synthesized and their potential to act as a dual-mode T_1 and T_2 MRI contrast agent was investigated in vitro and in vivo. The D-glucuronic acid coated GDO nanoparticles (d_a_v_g = 1.0 nm) showed large r_1 and r_2 values (r_2/r_1 ≈ 6.6) and as a result clear dose-dependent contrast enhancements in R_1 and R_2 map images. Finally, the dual-mode imaging capability of the nanoparticles was confirmed by obtaining in vivo T_1 and T_2 MR images. (paper)

Mott transition in Ga-doped Mg{sub x}Zn{sub 1-x}O: A direct observation

Energy Technology Data Exchange (ETDEWEB)

Wei Wei; Nori, Sudhakar [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC (United States); Jin Chunming [Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Campus Box 7115, Raleigh, NC 27695-7115 (United States); Narayan, Jagdish [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC (United States); Narayan, Roger J., E-mail: roger_narayan@unc.edu [Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Campus Box 7115, Raleigh, NC 27695-7115 (United States); Ponarin, Dmtri; Smirnov, Alex [Department of Chemistry, North Carolina State University, Raleigh, NC (United States)

2010-07-25

This paper reports the direct evidence for Mott transition in Ga-doped Mg{sub x}Zn{sub 1-x}O thin films. Highly transparent Ga-doped Mg{sub x}Zn{sub 1-x}O thin films were grown on c-plane sapphire substrates using pulsed laser deposition. 0.1 at.%, 0.5 at.% and 1 at.% Ga-doped Mg{sub 0.1}Zn{sub 0.9}O films were selected for resistivity measurements in the temperature range from 250 K to 40 mK. The 0.1 at.% Ga-doped Mg{sub 0.1}Zn{sub 0.9}O thin film showed typical insulator-like behavior and the 1 at.% Ga-doped Mg{sub 0.1}Zn{sub 0.9}O thin film showed typical metal-like behavior. The 0.5 at.% Ga-doped Mg{sub 0.1}Zn{sub 0.9}O film showed increasing resistivity with decreasing temperature; resistivity was saturated with a value of 1.15 x 10{sup -2} {Omega} cm at 40 mK, which is characteristic of the metal-insulator transition region. Temperature-dependent conductivity {sigma}(T) in the low temperature range revealed that the electron-electron scattering is the dominant dephasing mechanism. The inelastic scattering time is found to vary as T{sup -3/2}.

Uniform silver/polypyrrole core-shell nanoparticles synthesized by hydrothermal reaction

Energy Technology Data Exchange (ETDEWEB)

Wang Shibin [Department of Chemistry, Tsinghua University, Beijing 100084 (China); Shi Gaoquan [Department of Chemistry, Tsinghua University, Beijing 100084 (China)]. E-mail: gshi@tsinghua.edu.cn

2007-04-15

Uniformly sized silver/polypyrrole (Ag/PPy) core-shell nanoparticles were synthesized by one-step hydrothermal reaction of pyrrole and silver nitrate in the presence of polyvinyl pyrrolidone (PVP) as protection agent. The morphology and structures of the nanoparticles have been studied by scanning and transmission electronic microscopes, X-ray diffractometer and Raman spectroscopy. The experimental results indicated that the particles had 120 nm silver cores with 20 nm polypyrrole (PPy) coatings. The reaction conditions have strong effects on the morphology of the nanoparticles.

Uniform silver/polypyrrole core-shell nanoparticles synthesized by hydrothermal reaction

International Nuclear Information System (INIS)

Wang Shibin; Shi Gaoquan

2007-01-01

Uniformly sized silver/polypyrrole (Ag/PPy) core-shell nanoparticles were synthesized by one-step hydrothermal reaction of pyrrole and silver nitrate in the presence of polyvinyl pyrrolidone (PVP) as protection agent. The morphology and structures of the nanoparticles have been studied by scanning and transmission electronic microscopes, X-ray diffractometer and Raman spectroscopy. The experimental results indicated that the particles had 120 nm silver cores with 20 nm polypyrrole (PPy) coatings. The reaction conditions have strong effects on the morphology of the nanoparticles

Study of Ag and Au Nanoparticles Synthesized by Arc Discharge in Deionized Water

Directory of Open Access Journals (Sweden)

Der-Chi Tien

2010-01-01

Full Text Available The paper presents a study of Ag and Au nanofluids synthesized by the arc discharge method (ADM in deionized water. The metallic Ag nanoparticle (Ag0 and ionic Ag (Ag+ have played an important role in the battle against germs which are becoming more drug-resistant every year. Our study indicates that Ag nanoparticle suspension (SNPS fabricated by using ADM without added surfactants exclusively contains the metallic Ag nanoparticle and ionic Ag. Besides that, the ADM in deionized water has also been employed for the fabrication process of Au nanoparticles. The experimental results indicate that the prepared Ag nanoparticles can react with the dissolved H2CO3 in deionized water, leading to the formation of Ag2CO3. Significantly different to Ag, the prepared Au nanoparticles with their surfaces bonded by oxygen are suspended in deionized water by the formation of hydrogen bonded with the neighboring water molecules.

Sonochemically synthesized biocompatible zirconium phosphate nanoparticles for pH sensitive drug delivery application

Energy Technology Data Exchange (ETDEWEB)

Kalita, Himani, E-mail: hkalita74@gmail.com [Department of Chemistry, Indian Institute of Technology Kharagpur, West Bengal 721302 (India); Prashanth Kumar, B.N., E-mail: prasanthkumar999@gmail.com [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, West Bengal 721302 (India); Konar, Suraj, E-mail: suraj.konar@gmail.com [Department of Chemistry, Indian Institute of Technology Kharagpur, West Bengal 721302 (India); Tantubay, Sangeeta, E-mail: sang.chem2@gmail.com [Department of Chemistry, Indian Institute of Technology Kharagpur, West Bengal 721302 (India); Mahto, Madhusudan Kr., E-mail: mahtomk0@gmail.com [Department of Chemistry, Indian Institute of Technology Kharagpur, West Bengal 721302 (India); Mandal, Mahitosh, E-mail: mahitosh@smst.iitkgp.ernet.in [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, West Bengal 721302 (India); Pathak, Amita, E-mail: ami@chem.iitkgp.ernet.in [Department of Chemistry, Indian Institute of Technology Kharagpur, West Bengal 721302 (India)

2016-03-01

The present work reports the synthesis of biocompatible zirconium phosphate (ZP) nanoparticles as nanocarrier for drug delivery application. The ZP nanoparticles were synthesized via a simple sonochemical method in the presence of cetyltrimethylammonium bromide and their efficacy for the delivery of drugs has been tested through various in-vitro experiments. The particle size and BET surface area of the nanoparticles were found to be ~ 48 nm and 206.51 m{sup 2}/g respectively. The conventional MTT assay and cellular localization studies of the particles, performed on MDA-MB-231 cell lines, demonstrate their excellent biocompatibility and cellular internalization behavior. The loading of curcumin, an antitumor drug, onto the ZP nanoparticles shows the rapid drug uptake ability of the particles, while the drug release study, performed at two different pH values (at 7.4 and 5) depicts pH sensitive release-profile. The MTT assay and cellular localization studies revealed higher cellular inhibition and better bioavailability of the nanoformulated curcumin compared to free curcumin. - Highlights: • Biocompatible zirconium phosphate nanoparticles were synthesized by a simple sonochemical approach. • Curcumin was rapidly loaded onto the particles by the aid by hydrogen bond formation. • The curcumin loaded zirconium phosphate nanoparticles depict pH triggered drug release phenomenon. • The nanoformulated curcumin showed enhanced anti-tumor activity as compared to the native curcumin.

Sonochemically synthesized biocompatible zirconium phosphate nanoparticles for pH sensitive drug delivery application

International Nuclear Information System (INIS)

Kalita, Himani; Prashanth Kumar, B.N.; Konar, Suraj; Tantubay, Sangeeta; Mahto, Madhusudan Kr.; Mandal, Mahitosh; Pathak, Amita

2016-01-01

The present work reports the synthesis of biocompatible zirconium phosphate (ZP) nanoparticles as nanocarrier for drug delivery application. The ZP nanoparticles were synthesized via a simple sonochemical method in the presence of cetyltrimethylammonium bromide and their efficacy for the delivery of drugs has been tested through various in-vitro experiments. The particle size and BET surface area of the nanoparticles were found to be ~ 48 nm and 206.51 m"2/g respectively. The conventional MTT assay and cellular localization studies of the particles, performed on MDA-MB-231 cell lines, demonstrate their excellent biocompatibility and cellular internalization behavior. The loading of curcumin, an antitumor drug, onto the ZP nanoparticles shows the rapid drug uptake ability of the particles, while the drug release study, performed at two different pH values (at 7.4 and 5) depicts pH sensitive release-profile. The MTT assay and cellular localization studies revealed higher cellular inhibition and better bioavailability of the nanoformulated curcumin compared to free curcumin. - Highlights: • Biocompatible zirconium phosphate nanoparticles were synthesized by a simple sonochemical approach. • Curcumin was rapidly loaded onto the particles by the aid by hydrogen bond formation. • The curcumin loaded zirconium phosphate nanoparticles depict pH triggered drug release phenomenon. • The nanoformulated curcumin showed enhanced anti-tumor activity as compared to the native curcumin.

Antimicrobial potential of green synthesized CeO2 nanoparticles from Olea europaea leaf extract.

Science.gov (United States)

Maqbool, Qaisar; Nazar, Mudassar; Naz, Sania; Hussain, Talib; Jabeen, Nyla; Kausar, Rizwan; Anwaar, Sadaf; Abbas, Fazal; Jan, Tariq

This article reports the green fabrication of cerium oxide nanoparticles (CeO 2 NPs) using Olea europaea leaf extract and their applications as effective antimicrobial agents. O. europaea leaf extract functions as a chelating agent for reduction of cerium nitrate. The resulting CeO 2 NPs exhibit pure single-face cubic structure, which is examined by X-ray diffraction, with a uniform spherical shape and a mean size 24 nm observed through scanning electron microscopy and transmission electron microscopy. Ultraviolet-visible spectroscopy confirms the characteristic absorption peak of CeO 2 NPs at 315 nm. Fourier transform infrared spectroscopy reflects stretching frequencies at 459 cm -1 , showing utilization of natural components for the production of NPs. Thermal gravimetric analysis predicts the successful capping of CeO 2 NPs by bioactive molecules present in the plant extract. The antimicrobial studies show significant zone of inhibition against bacterial and fungal strains. The higher activities shown by the green synthesized NPs than the plant extract lead to the conclusion that they can be effectively used in biomedical application. Furthermore, reduction of cerium salt by plant extract will reduce environmental impact over chemical synthesis.

Exchange of TiO2 nanoparticles between streams and streambeds.

Science.gov (United States)

Boncagni, Natalia Ticiana; Otaegui, Justo Manuel; Warner, Evelyn; Curran, Trisha; Ren, Jianhong; de Cortalezzi, Maria Marta Fidalgo

2009-10-15

The expanding use of manufactured nanoparticles has increased the potential for their release into the natural environment. Particularly, TiO2 nanoparticles pose significant exposure risk to humans and other living species due to their extensive use in a wide range of fields. To better understand the environmental and health risks associated with the release of TiO2 nanoparticles, knowledge on their fate and transport is needed. This study evaluates the transport of two different TiO2 nanoparticles: one commercially available (P25 TiO2 and the other synthesized at a lab scale (synthesized TiO2). Laboratory flume, column, and batch experiments were conducted to investigate the processes dominating the transport of TiO2 nanoparticles between streams and streambeds and to characterize the properties of these nanoparticles under different physicochemical conditions. Results show that the synthesized TiO2 was more stable compared to the P25 TiO2, which underwent significant aggregation under the same experimental conditions. As a result, P25 TiO2 deposited at a faster rate than the synthesized TiO2 in the streambed. Both types of TiO2 nanoparticles deposited in the streambed were easily released when the stream velocity was increased. The aggregation and deposition of P25 TiO2 were highly dependent on pH. A process-based colloid exchange model was applied to interpret the observed transport behavior of the TiO2 nanoparticles.

Mn doped GaN nanoparticles synthesized by rapid thermal treatment in ammonia

International Nuclear Information System (INIS)

Šimek, P.; Sedmidubský, D.; Huber, Š.; Klímová, K.; Maryško, M.; Mikulics, M.; Sofer, Z.

2015-01-01

We present a novel route for the synthesis of manganese doped GaN nanoparticles. Nanoparticles in the form of hexagonal discs were synthesized by rapid thermal treatment of manganese doped ammonium hexafluorogallate in ammonium atmosphere. The morphology of GaN:Mn nanoparticles was investigated using scanning electron microscopy. A concentration over 0.7 wt.% of Mn was observed by X-ray fluorescence and electron microprobe. Structural and electronic properties were investigated using X-ray diffraction, Raman spectroscopy and micro-photoluminescence with excitation wavelength of 325 nm and 532 nm. The magnetic properties between 4.5 K and 300 K were investigated by a superconducting quantum interference device (SQUID) magnetometer. GaN:Mn nanoparticles show a purely paramagnetic behavior which can be interpreted in terms of Mn 2+ ions exhibiting an antiferromagnetic interaction. - Highlights: • A new method for the synthesis of Mn doped GaN nanoparticles. • GaN:Mn nanoparticles form hexagonal discs. • None ferromagnetic ordering observed in GaN:Mn nanoparticles. • The concentration of Mn in GaN:Mn nanoparticles reach up to 0.8 wt.%

Anodic stripping voltammetry of synthesized CdS nanoparticles at boron-doped diamond electrodes

Energy Technology Data Exchange (ETDEWEB)

Hayat, Mohammad; Ivandini, Tribidasari A., E-mail: ivandini.tri@sci.ui.ac.id; Saepudin, Endang [Department of Chemistry, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Einaga, Yasuaki [Department of Chemistry, Keio University (Japan)

2016-04-19

Cadmium sulphide (CdS) nanoparticles were chemically synthesized using reverse micelles microreactor methods. By using different washing treatments, UV-Vis spectroscopy showed that the absorption peaks appeared at 465 nm, 462 nm, 460 nm, and 459 nm respectively for CdS nanoparticles without and with 1, 2, and 3 times washing treatments using pure water. In comparison with the absorbance peak of bulk CdS at 512 nm, the shifted absorption peaks, indicates that the different sizes of CdS can be prepared. Anodic stripping voltammetry of the CdS nanoparticles was then studied at a boron-doped diamond electrode using 0.1 M KClO{sub 4} and 0.1 M HClO{sub 4} as the electrolytes. A scan rate of 100 mV/s with a deposition potential of -1000 mV (vs. Ag/AgCl) for 60 s at a potential scan from -1600 mV to +800 mV (vs. Ag/AgCl) was applied as the optimum condition of the measurements. Highly-accurate linear calibration curves (R{sup 2} = 0.99) in 0.1 M HClO{sub 4} with the sensitivity of 0.075 mA/mM and the limit of detection of 81 µM in 0.1 M HClO{sub 4} can be achieved, which is promising for an application of CdS nanoparticles as a label for biosensors.

Fine tuning of size and morphology of magnetite nanoparticles synthesized by microemulsion

Science.gov (United States)

Singh, Pinki; Upadhyay, Chandan

2018-05-01

The synthesis parameters crucially affect the physical and chemical parameters of nanoparticles. Magnetite (Fe3O4) nanoparticles were synthesized using microemulsion method. This method does not require high temperature synthesis, nitrogen environment and/or pH regulation during synthesis process. We are presenting here a systematic study on role of different associated parameters of microemulsion synthesis method on the formation of Fe3O4 nanoparticles. From X-ray Diffraction and Transmission Electron Micoscopy data analysis the size of synthesized particles were observed to be <10 nm. The critical concentration of ferrous-ferric solution to obtain particles in single phase has been found to be ≤0.09 M and ≤0.184 M, respectively. The variation of molar concentration (0.01 M ≤x≤ 0.1 M) of CTAB leads to formation of Fe3O4 nano-scale particles of distinct morphologies e.g. nano-cubes, pentagons and spheres. The number of ferrous and ferric ions involved in the formation decides the size of the nanoparticles. The single crystallographic phase is obtained in reaction temperature range of 65° C

Investigation of Structural, Morphological, Magnetic Properties and Biomedical applications of Cu2+ Substituted Uncoated Cobalt Ferrite Nanoparticles

Directory of Open Access Journals (Sweden)

M. Margabandhu

Full Text Available ABSTRACT In the present work, Cu2+ substituted cobalt ferrite (Co1-xCuxFe2O4, x = 0, 0.3, 0.5, 0.7 and 1 magnetic nanopowders were synthesized via chemical co-precipitation method. The prepared powders were investigated by various characterization methods such as X-ray diffraction analysis (XRD, scanning electron microscope analysis (SEM, vibrating sample magnetometer analysis (VSM and fourier transform infrared spectroscopy analysis (FTIR. The XRD analysis reveals that the synthesized nanopowders possess single phase centred cubic spinel structure. The average crystallite size of the particles ranging from 27-49 nm was calculated by using Debye-scherrer formula. Magnetic properties of the synthesized magnetic nanoparticles are studied by using VSM. The VSM results shows the magnetic properties such as coercivity, magnetic retentivity decreases with increase in copper substitution whereas the saturation magnetization shows increment and decrement in accordance with Cu2+ substitution in cobalt ferrite nanoparticles. SEM analysis reveals the morphology of synthesized magnetic nanoparticles. FTIR spectra of Cu2+ substituted cobalt ferrite magnetic nanoparticles were recorded in the frequency range 4000-400cm-1. The spectrum shows the presence of water adsorption and metal oxygen bonds. The adhesion nature of Cu2+ substituted cobalt ferrite magnetic nanoparticles with bacteria in reviewed results indicates that the synthesized nanoparticles could be used in biotechnology and biomedical applications.

A novel sol–gel process to facilely synthesize Ni{sub 3}Fe nanoalloy nanoparticles supported with carbon and silica

Energy Technology Data Exchange (ETDEWEB)

Xu, L.Q. [Institute of Materials Engineering, Nanjing National Laboratory of Microstructures, Jiangsu Provincial Laboratory for Nanotechnology and School of Physics, Nanjing University, Nanjing 210093 (China); School of Physics and Information Technology, Ningxia Teachers University, Guyuan, Ningxia 756000 (China); Chen, L.Y.; Huang, H.F.; Xie, R.; Xia, W.B.; Wei, J.; Zhong, W. [Institute of Materials Engineering, Nanjing National Laboratory of Microstructures, Jiangsu Provincial Laboratory for Nanotechnology and School of Physics, Nanjing University, Nanjing 210093 (China); Tang, S.L., E-mail: tangsl@nju.edu.cn [Institute of Materials Engineering, Nanjing National Laboratory of Microstructures, Jiangsu Provincial Laboratory for Nanotechnology and School of Physics, Nanjing University, Nanjing 210093 (China); Du, Y.W. [Institute of Materials Engineering, Nanjing National Laboratory of Microstructures, Jiangsu Provincial Laboratory for Nanotechnology and School of Physics, Nanjing University, Nanjing 210093 (China)

2014-04-01

Graphical abstract: The TEM and HRTEM images and the magnetization curves taken in both zero-field-cooled (ZFC) and field-cooled (FC) modes of Ni{sub 3}Fe nanoparticles calcined at 300 °C for 2 h under Ar flowing. Display Omitted - Highlights: • Ultrafine Ni{sub 3}Fe nanoalloy nanoparticles were synthesized via a modified novel sol–gel process. • The prepared Ni{sub 3}Fe nanoalloy nanoparticles have a narrow size distribution. • The Ni{sub 3}Fe nanoparticles exhibit superparamagnetic behaviors at room temperature. - Abstract: In this paper, we present a modified novel silica sol–gel process and explored the possibility, for the first time, to synthesize binary nanoalloy nanoparticles. We successfully prepared ultrafine Ni{sub 3}Fe nanoparticles supported with carbon and silica via this simple one-pot reaction without H{sub 2} reduction. X-ray diffraction (XRD) and selected area electron diffraction (SAED) investigations of the Ni{sub 3}Fe nanoparticles show that the nanoparticles have a face-centered-cubic (fcc) crystal structure. The TEM images show that grain sizes of Ni{sub 3}Fe nanoparticles have a narrow size distribution. Moreover, the grain size of the nanoparticles is not very sensitive to the elevated annealing temperature. The Ni{sub 3}Fe nanoparticles exhibit typical superparamagnetic behavior at room temperature, and the blocking temperatures (T{sub B}) are determined by the temperature-dependent magnetization (M–T curves) measurements. This novel silica sol–gel method is expected to have broad applications in synthesizing nanoalloy nanoparticles.

Absence of intrinsic ferromagnetism in Zn{sub 1-x}Mn{sub x}O alloys

Energy Technology Data Exchange (ETDEWEB)

Zhang Huawei [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Shi Erwei [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Chen Zhizhan [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Liu Xuechao [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Xiao Bing [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

2006-10-04

Zn{sub 1-x}Mn{sub x}O alloys, with different Mn concentrations, were prepared by the hydrothermal method. X-ray diffraction and electron paramagnetic resonance spectra demonstrate that Zn{sup 2+} ions are homogeneously substituted by Mn{sup 2+} ions without changing the ZnO wurtzite structure. The x = 0.02 and 0.04 samples are paramagnetic. When the Mn concentrations are increased to x = 0.08 and 0.10, the samples exhibit some ferromagnetism due to a secondary phase (Zn,Mn)Mn{sub 2}O{sub 4}. (letter to the editor)

Glycol stabilized magnetic nanoparticles for photocatalytic degradation of xylenol orange

Science.gov (United States)

Ullah, Ikram; Ali, Farman; Ali, Zarshad; Humayun, Muhammad; wahab, Zain Ul

2018-05-01

In this work, we have successfully prepared ZnFe2O4 magnetic nanoparticles as photocatalysts via co-precipitation method using triethylene glycol as a stabilizing agent. The resultant nanoparticles were annealed at 400 °C and then acid etched and surface functionalized with 3-(triethoxysilyl) propyl amine (APTES). Fourier transform infrared (FTIR) spectroscopy and x-ray diffraction (XRD) analysis were used to characterize these magnetic photocatalysts. XRD patterns revealed that the size of annealed and functionalized ZnFe2O4 nanoparticles falls in the range of 23.3 and 13.9 nm, respectively. The optical band gaps of the magnetic photocatalysts were calculated from UV–Visible absorption spectra using Tauc plots. The band gap of the ZnFe2O4 photocatalyst in acidic and basic medium was 2.47 and 2.7 eV, respectively. The performance of the magnetic photocatalysts was evaluated for xylenol orange (XO) degradation. The degradation rates of XO dye for the blank, annealed and functionalized photocatalysts at pH = 4 were 76%, 85%, and 90%, respectively. In addition, the influence of important parameters such as contact time, pH, catalyst, and dye dose were also investigated for all the three photocatalysts. The applied kinetics models demonstrated that the degradation followed pseudo 1st order.

Study of phase development and thermal stability in as synthesized TiO2 nanoparticles by laser pyrolysis: ethylene uptake and oxygen enrichment

Science.gov (United States)

Ilie, Alina Georgiana; Scarisoreanu, Monica; Dutu, Elena; Dumitrache, Florian; Banici, Ana-Maria; Fleaca, Claudiu Teodor; Vasile, Eugenia; Mihailescu, Ion

2018-01-01

Laser pyrolysis has proven a viable and trustworthy method of TiO2 nanoparticles fabrication, ensuring good quality and wide variety of nanoparticle morphologies and sizes. This work is aimed to phase control, experimentally studied, by parameter modulation, during one step laser pyrolysis synthesis or in combination with thermal annealing. High phase purity anatase and rutile TiO2 nanoparticles, oxygen abundant, are synthesized from TiCl4 and C2H4 gas mixtures, in the presence of air as oxygen donor, under CO2 laser radiation. The nano-titania samples are analyzed by X-ray Diffraction, EDAX, TEM and Raman spectroscopy and reveal good phase stability and distinct morphology. This study extends the method applicability onto rutile majoritarian TiO2 synthesis and generation of thermally stable anatase titania, a well-known catalyst.

Effect of solvent on the synthesis of SnO_2 nanoparticles

International Nuclear Information System (INIS)

Kumar, Virender; Singh, Karamjit; Singh, Kulwinder; Kumar, Akshay; Kumari, Sudesh; Thakur, Anup

2016-01-01

Tin oxide (SnO_2) nanoparticles have been synthesized by co-precipitation method. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD) and Ultraviolet-Visible spectroscopy (UV-VIS). XRD analysis confirmed the formation of single phase of SnO_2 nanoparticles. It has been found that solvents played important role in controlling the crystallite size of SnO_2 nanoparticles. The XRD analysis showed well crystallized tetragonal SnO_2 nanoparticles. The crystallite size of SnO_2 nanoparticles varies with the solvent. Tauc plot showed that optical band gap was also tailored by controlling the solvent during synthesis.

Oxide nanoparticle-based fabrication and optical properties of Cu(In{sub 1−x}Ga{sub x})S{sub 2} absorber layer for solar cells

Energy Technology Data Exchange (ETDEWEB)

Choi, Yo-Min [Department of Fusion Chemical Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Lee, Young-In [Institute of Nanosensor Technology, Hanyang University, Ansan 426-791 (Korea, Republic of); Kim, Bum-Sung [Production Technology R and D Division, Korea Institute of Industrial Technology, Incheon 406-840 (Korea, Republic of); Choa, Yong-Ho, E-mail: choa15@hanyang.ac.kr [Department of Fusion Chemical Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Institute of Nanosensor Technology, Hanyang University, Ansan 426-791 (Korea, Republic of)

2013-11-01

The compound Cu(In{sub 1−x}Ga{sub x})S{sub 2} (CIGS) was synthesized using copper oxide, indium oxide and gallium oxide mixture (CIGO) nanoparticles using salt-assisted ultrasonic spray pyrolysis (SAUSP). Under this method, CIGS can be produced without the complicated restrictions of a vacuum and an inert atmosphere. The band gap of CIGS can be controlled by introducing the desired stoichiometric quantities of starting materials. In order to synthesize CIGO nanoparticles, various NaCl/precursor ratios were used to accomplish the SAUSP process and ultimately monodisperse CIGO nanoparticles with average particle size of 9 nm without hard agglomeration were obtained. Subsequently, the CIGO nanoparticles were sulfurized to form the CIGS in H{sub 2}S/Ar atmosphere at 500 °C. The CIGS obtained in the present study has the various band gap ranging from 1.67 to 2.34 eV depending on the Ga / (In + Ga) ratio, and those band gap correspond to the respective bulk materials. - Highlights: • CIGS is obtained using Cu, In and Ga oxide mixture (CIGO) nanoparticles. • Salt-assisted ultrasonic spray pyrolysis is used to synthesize CIGO nanoparticles. • Nine nanometers of monodisperse CIGO nanoparticles without hard agglomeration is obtained. • The band gap of CIGS can be controlled by introducing the desired ratio of precursor.

Evaluation of antioxidant, antibacterial and cytotoxic effects of green synthesized silver nanoparticles by Piper longum fruit

International Nuclear Information System (INIS)

Reddy, N. Jayachandra; Nagoor Vali, D.; Rani, M.; Rani, S. Sudha

2014-01-01

Silver nanoparticles synthesized through bio-green method has been reported to have biomedical applications to control pathogenic microbes as it is cost effective compared to commonly used physical and chemical methods. In present study, silver nanoparticles were synthesized using aqueous Piper longum fruit extract (PLFE) and confirmed by UV–visible spectroscopy. The nanoparticles were spherical in shape with an average particle size of 46 nm as determined by scanning electronic microscopy (SEM) and dynamic light scattering (DLS) particle size analyzer respectively. FT-IR spectrum revealed the capping of the phytoconstituents, probably polyphenols from P. longum fruit extract and stabilizing the nanoparticles. Further the ferric ion reducing test, confirmed that the capping agents were condensed tannins. The aqueous P. longum fruit extract (PLFE) and the green synthesized silver nanoparticles (PLAgNPs) showed powerful antioxidant properties in in vitro antioxidant assays. The results from the antimicrobial assays suggested that green synthesized silver nanoparticles (PLAgNPs) were more potent against pathogenic bacteria than the P. longum fruit extract (PLFE) alone. The nanoparticles also showed potent cytotoxic effect against MCF-7 breast cancer cell lines with an IC 50 value of 67 μg/ml/24 h by the MTT assay. These results support the advantages of using bio-green method for synthesizing silver nanoparticles with antioxidant, antimicrobial and cytotoxic activities those are simple and cost effective as well. - Highlights: • 46 nm spherical shaped P. longum fruit silver nanoparticles was prepared. • Capping and reducing bioactive plant compounds with in nanoparticles were condensed tannins. • Particles are potent antioxidant and anti microbial in biological systems. • They are cytotoxic against MCF-7 cell lines

Evaluation of antioxidant, antibacterial and cytotoxic effects of green synthesized silver nanoparticles by Piper longum fruit

Energy Technology Data Exchange (ETDEWEB)

Reddy, N. Jayachandra; Nagoor Vali, D.; Rani, M.; Rani, S. Sudha, E-mail: sadrassudha@gmail.com

2014-01-01

Silver nanoparticles synthesized through bio-green method has been reported to have biomedical applications to control pathogenic microbes as it is cost effective compared to commonly used physical and chemical methods. In present study, silver nanoparticles were synthesized using aqueous Piper longum fruit extract (PLFE) and confirmed by UV–visible spectroscopy. The nanoparticles were spherical in shape with an average particle size of 46 nm as determined by scanning electronic microscopy (SEM) and dynamic light scattering (DLS) particle size analyzer respectively. FT-IR spectrum revealed the capping of the phytoconstituents, probably polyphenols from P. longum fruit extract and stabilizing the nanoparticles. Further the ferric ion reducing test, confirmed that the capping agents were condensed tannins. The aqueous P. longum fruit extract (PLFE) and the green synthesized silver nanoparticles (PLAgNPs) showed powerful antioxidant properties in in vitro antioxidant assays. The results from the antimicrobial assays suggested that green synthesized silver nanoparticles (PLAgNPs) were more potent against pathogenic bacteria than the P. longum fruit extract (PLFE) alone. The nanoparticles also showed potent cytotoxic effect against MCF-7 breast cancer cell lines with an IC 50 value of 67 μg/ml/24 h by the MTT assay. These results support the advantages of using bio-green method for synthesizing silver nanoparticles with antioxidant, antimicrobial and cytotoxic activities those are simple and cost effective as well. - Highlights: • 46 nm spherical shaped P. longum fruit silver nanoparticles was prepared. • Capping and reducing bioactive plant compounds with in nanoparticles were condensed tannins. • Particles are potent antioxidant and anti microbial in biological systems. • They are cytotoxic against MCF-7 cell lines.

Synthesize and characterization of a novel anticorrosive cobalt ferrite nanoparticles dispersed in silica matrix (CoFe2O4-SiO2) to improve the corrosion protection performance of epoxy coating

International Nuclear Information System (INIS)

Gharagozlou, M.; Ramezanzadeh, B.; Baradaran, Z.

2016-01-01

Highlights: • An anticorrosive cobalt ferrite nanopigment dispersed in silica matrix was synthesized. • The nanopigment showed proper inhibition performance in solution study. • The nanopigment significantly improved the corrosion resistance of the epoxy coating. - Abstract: This study aimed at studying the effect of an anticorrosive nickel ferrite nanoparticle dispersed in silica matrix (NiFe 2 O 4 -SiO 2 ) on the corrosion protection properties of steel substrate. NiFe 2 O 4 and NiFe 2 O 4 -SiO 2 nanopigments were synthesized and then characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscope (TEM). Then, 1 wt.% of nanopigments was dispersed in an epoxy coating and the resultant nanocomposites were applied on the steel substrates. The corrosion inhibition effects of nanopigments were tested by an electrochemical impedance spectroscopy (EIS) and salt spray test. Results revealed that dispersing nickel ferrite nanoparticles in a silica matrix (NiFe 2 O 4 -SiO 2 ) resulted in the enhancement of the nanopigment dispersion in the epoxy coating matrix. Inclusion of 1 wt.% of NiFe 2 O 4 -SiO 2 nanopigment into the epoxy coating enhanced its corrosion protection properties before and after scratching.

Photochemical synthesis of UO2 nanoparticles

International Nuclear Information System (INIS)

Rath, M.C.; Keny, Sangeeta; Naik, D.B.

2014-01-01

UO 2 nanoparticles have been recently synthesized by us from aqueous solutions of uranyl nitrate through radiolytic method on high-energy electron beam irradiation. In this study, the synthesis of UO 2 nanoparticles through photochemical method is reported which is a complementary route to radiation chemical method

Structural and electrochemical properties of La 0.8Sr 0.2Ga 1-xFe xO 3

Science.gov (United States)

Mori, Kazuhiro; Onodera, Yohei; Kiyanagi, Ryoji; Richardson, James W.; Itoh, Keiji; Sugiyama, Masaaki; Kamiyama, Takashi; Fukunaga, Toshiharu

2009-02-01

Mixed ionic-electronic conductor of Fe doped lanthanum gallate, La 0.8Sr 0.2Ga 1-xFe xO 3, has been studied by the dc four-probe method and the neutron powder diffraction. In the electrical conductivity measurement at RT, insulator-metal transition-like phenomenon was observed at around x˜0.35; this suggests an existence of the percolation limit for the electronic conductivity. Simultaneously, a bond length between O atoms, lO-O, in a MO 6 octahedron (M dbnd Ga 1-xFe x) drastically expands over x˜0.4, according to the result of crystal structure refinement based on the hexagonal phase. Such a drastic expansion in the lO-O would induce the decrease in the oxygen ionic conductivity.

Bioimaging of M1 cells using ceramic nanophosphors: Synthesis and toxicity assay of Y2O3 nanoparticles

International Nuclear Information System (INIS)

Venkatachalam, N; Soga, K; Tsuji, T; Okumura, Y; Fukuda, R

2009-01-01

Er 3+ doped Y 2 O 3 nanoparticles were synthesized by enzymatic and polymer-assisted homogeneous co-precipitation methods. Resultant particle size is about 30-40 nm with narrow size distribution whereas the particle size is smaller than those acquired by conventional homogeneous and alkali precipitation methods. The particles shows bright green (550 nm) and red (660 nm) upconversion (UC) as well as near infrared (NIR) fluorescence (1550 nm) under 980 nm excitation. Bioimaging of M1 cells using the nanoparticles were successfully attempted. It is observed that 0.5 mg/ml of nanoparticles is the nominal concentration for bioimaging of M1 cells under the physiological conditions. The cellular uptake of nanoparticles is evidenced from bright field, UC and NIR fluorescence images of live M1 cells. Our studies suggest that lower concentration of nanoparticles is sufficient for imaging when the particles are taken in the M1 cells and also the concentration can keep the cells alive. Further it was demonstrated that under the physiological conditions, Y 2 O 3 nanoparticles emit UC and NIR fluorescence in M1 cells even after the surface modification with PEG-b-PAAc polymer. Moreover, surface modified nanoparticles shows lower toxic effect in M1 cells while compare to bare nanoparticles.

Sensing and electrical properties of TiO2 nanoparticles

International Nuclear Information System (INIS)

Usman, M.

2011-01-01

The purpose of this work was to synthesize TiO 2 nanoparticles using Coprecipitation method. 2 different samples were synthesized, one with a modifier and other without using a modifier. After synthesis, newly formed nanoparticles were characterized b different techniques to find various properties of these nanoparticles. Scanning electron Microscopy (SEM) was used to study structure and morphology of Cu nanoparticles and for compositional analysis Energy dispersive spectroscopy (EDS) was used. X-Ray Diffraction (XRD) Studies were also carried out to find phase an average particle Size. To find the band gap of our nanoparticles, UV-Visible Spectroscopy was also done. Non-Modified nanoparticles were as small as 12nm reported by SEM images which were synthesized using a modifier were as small as 10nm. Modified TiO 2 nanoparticles were used in humidity sensing devices and it properties as a humidity sensor were examined by doing Impedance spectroscopy, D measurements and Dielectric measurements. Our TiO 2 humidity sensor showed sensitivity for humidity at low and mid-range frequencies while its response time was 4 seconds when we changed RH% to 90 from 40% and measured the impedance. (author)

Uncapped silver nanoparticles synthesized by DC arc thermal plasma technique for conductor paste formulation

Science.gov (United States)

Shinde, Manish; Pawar, Amol; Karmakar, Soumen; Seth, Tanay; Raut, Varsha; Rane, Sunit; Bhoraskar, Sudha; Amalnerkar, Dinesh

2009-11-01

Uncapped silver nanoparticles were synthesized by DC arc thermal plasma technique. The synthesized nanoparticles were structurally cubic and showed wide particle size variation (between 20-150 nm). Thick film paste formulated from such uncapped silver nanoparticles was screen-printed on alumina substrates and the resultant `green' films were fired at different firing temperatures. The films fired at 600 °C revealed better microstructure properties and also yielded the lowest value of sheet resistance in comparison to those corresponding to conventional peak firing temperature of 850 °C. Our findings directly support the role of silver nanoparticles in substantially depressing the operative peak firing temperature involved in traditional conductor thick films technology.

Synthesized of PEG-6000 coated MgFe2O4 nanoparticles based on natural iron sand by co-precipitation method

Science.gov (United States)

Setiadi, E. A.; Simbolon, S.; Saputra, A. S. P.; Marlianto, E.; Djuhana; Kurniawan, C.; Yunus, M.; Sebayang, P.

2018-02-01

The polymer coated Magnesium Ferrite nanoparticles (MgFe2O4) based on natural iron sand, Mg(CH3COO)2.4H2O, and PEG-6000 have been successfully prepared by co-precipitation method. The mass variation of PEG-6000 content was from 0 to 12 gram. It was prepared at synthesize temperature of 70°C. The PEG coating reduced the effect of agglomeration, so the coercivity value can be closed to soft magnets. The nanoparticle of synthesized has MgFe2O4 single phase and cubic spinel structure. The bonding of MgFe2O4 and PEG-6000 as a coating material was confirmed by FTIR curve. The MgFe2O4 density decreased with the increasing of PEG 6000 content. On the other hand, the coercivity value was slightly reduced as the addition of PEG-6000, with the lowest value was obtained on 8 gram PEG content. The optimum condition is obtained at addition of 8 gram PEG 6000 to MgFe2O4, with coercivity, saturation, and remanence are 198.41 Oe, 52.53 emu/g, and 8.51 emu/g, respectively. So that, the sample is widely used as absorbance material of heavy metal.

Structural, morphological, and optical properties of tin(IV) oxide nanoparticles synthesized using Camellia sinensis extract: a green approach

Science.gov (United States)

Selvakumari, J. Celina; Ahila, M.; Malligavathy, M.; Padiyan, D. Pathinettam

2017-09-01

Tin oxide (SnO2) nanoparticles were cost-effectively synthesized using nontoxic chemicals and green tea ( Camellia sinensis) extract via a green synthesis method. The structural properties of the obtained nanoparticles were studied using X-ray diffraction, which indicated that the crystallite size was less than 20 nm. The particle size and morphology of the nanoparticles were analyzed using scanning electron microscopy and transmission electron microscopy. The morphological analysis revealed agglomerated spherical nanoparticles with sizes varying from 5 to 30 nm. The optical properties of the nanoparticles' band gap were characterized using diffuse reflectance spectroscopy. The band gap was found to decrease with increasing annealing temperature. The O vacancy defects were analyzed using photoluminescence spectroscopy. The increase in the crystallite size, decreasing band gap, and the increasing intensities of the UV and visible emission peaks indicated that the green-synthesized SnO2 may play future important roles in catalysis and optoelectronic devices.

Sonochemically synthesized iron-doped zinc oxide nanoparticles: Influence of precursor composition on characteristics

International Nuclear Information System (INIS)

Roy, Anirban; Maitra, Saikat; Ghosh, Sobhan; Chakrabarti, Sampa

2016-01-01

Highlights: • Sonochemical synthesis of iron-doped zinc oxide nanoparticles. • Green synthesis without alkali at room temperature. • Characterization by UV–vis spectroscopy, FESEM, XRD and EDX. • Influence of precursor composition on characteristics. • Composition and characteristics are correlated. - Abstract: Iron-doped zinc oxide nanoparticles have been synthesized sonochemically from aqueous acetyl acetonate precursors of different proportions. Synthesized nanoparticles were characterized with UV–vis spectroscopy, X-ray diffraction and microscopy. Influences of precursor mixture on the characteristics have been examined and modeled. Linear correlations have been proposed between dopant dosing, extent of doping and band gap energy. Experimental data corroborated with the proposed models.

Characterization of ZnS nanoparticles synthesized by co-precipitation method

International Nuclear Information System (INIS)

Iranmanesh Parvaneh; Nourzpoor Mohsen; Saeednia Samira

2015-01-01

ZnS nanoparticles are prepared by homogeneous chemical co-precipitation method using EDTA as a stabilizer and capping agent. The structural, morphological, and optical properties of as-synthesized nanoparticles are investigated using x-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible (UV-Vis) absorption, and photoluminescence spectroscopy. The x-ray diffraction pattern exhibits a zinc-blended crystal structure at room temperature. The average particle size of the nanoparticles from the scanning electron microscopy image is about 50 nm. The ultraviolet absorption spectrum shows the blue shift in the band gap due to the quantum confinement effect. The photoluminescence spectrum of ZnS nanoparticles shows a blue visible spectrum. (paper)

Study of magnetic behavior in hexagonal-YMn1−xFexO3 (x=0 and 0.2) nanoparticles using remanent magnetization curves

International Nuclear Information System (INIS)

Chauhan, Samta; Singh, Amit Kumar; Srivastava, Saurabh Kumar; Chandra, Ramesh

2016-01-01

We have studied the magnetic behavior of YMn 1−x Fe x O 3 (x=0 and 0.2) nanoparticles synthesized by conventional solid state reaction method. The as-synthesized nanoparticles were found to have hexagonal phase with P6 3cm space group confirmed by X-Ray diffraction. The particle size was found to be ~70 nm as confirmed by both X-Ray diffraction and Transmission Electron Microscopy. DC magnetization and memory effect measurements imply that the h-YMnO 3 nanoparticles bear a resemblance to super spin-glass state following de Almeida–Thouless like behavior which is being suppressed by Fe-doping. The Fe-doping in YMnO 3 enhances the antiferromagnetic (AFM) transition temperature T N to ~79 K and induces a new magnetic state due to the surface spins which is realized as diluted antiferromagnet in a field (DAFF) as explored by the thermoremanent and isothermoremanent magnetization measured with different applied magnetic field. - Highlights: • Magnetic behavior of h-YMn 1−x Fe x O 3 (x=0 and 0.2) nanoparticles have been studied. • The nanoparticles (~70 nm) were synthesized by solid state reaction method. • Magnetic data reveal spin-glass behavior in YMnO 3 which was suppressed in YMn 0.8 Fe 0.2 O 3 . • The h-YMnO 3 nanoparticles show memory effect and obey de-Almeida Thouless line. • TRM and IRM suggest spin glass nature for YMnO 3 , while the YMn 0.8 Fe 0.2 O 3 resembles DAFF.

Potassium-doped copper oxide nanoparticles synthesized by a solvothermal method as an anode material for high-performance lithium ion secondary battery

International Nuclear Information System (INIS)

Thi, Trang Vu; Rai, Alok Kumar; Gim, Jihyeon; Kim, Jaekook

2014-01-01

A simple and efficient approach was developed to synthesize CuO nanoparticles with improved electrochemical performance. Potassium (K + )-doped CuO nanoparticles were synthesized by a simple and cost-effective solvothermal method followed by annealing at 500 °C for 5 h under air atmosphere. For comparison, an undoped CuO sample was also synthesized under the same conditions. X-ray diffraction analysis demonstrates that the K + ion doping caused no change in the phase structure, and highly crystalline K x Cu 1−x O 1−δ (x = 0.10) powder without any impurity was obtained. As an anode material for a lithium ion battery, the K + -doped CuO nanoparticle electrode exhibited better capacity retention with a reversible capacity of over 354.6 mA h g −1 for up to 30 cycles at 0.1 C, as well as a high charge capacity of 162.3 mA h g −1 at a high current rate of 3.2 C, in comparison to an undoped CuO electrode (275.9 mA h g −1 at 0.1 C and 68.9 mA h g −1 at 3.2 C). The high rate capability and better cycleability of the doped electrode can be attributed to the influence of the K + ion nanostructure on the increased electronic conductivity, diffusion efficiency, and kinetic properties of CuO during the lithiation and delithiation process.

Proximity hybridization-regulated catalytic DNA hairpin assembly for electrochemical immunoassay based on in situ DNA template-synthesized Pd nanoparticles

International Nuclear Information System (INIS)

Zhou, Fuyi; Yao, Yao; Luo, Jianjun; Zhang, Xing; Zhang, Yu; Yin, Dengyang; Gao, Fenglei; Wang, Po

2017-01-01

Novel hybridization proximity-regulated catalytic DNA hairpin assembly strategy has been proposed for electrochemical immunoassay based on in situ DNA template-synthesized Pd nanoparticles as signal label. The DNA template-synthesized Pd nanoparticles were characterized with atomic force microscopic and X-ray photoelectron spectroscopy. The highly efficient electrocatalysis by DNA template synthesized Pd nanoparticles for NaBH 4 oxidation produced an intense detection signal. The label-free electrochemical method achieved the detection of carcinoembryonic antigen (CEA) with a linear range from 10 −15 to 10 −11  g mL −1 and a detection limit of 0.43 × 10 −15  g mL −1 . Through introducing a supersandwich reaction to increase the DNA length, the electrochemical signal was further amplified, leading to a detection limit of 0.52 × 10 −16  g mL −1 . And it rendered satisfactory analytical performance for the determination of CEA in serum samples. Furthermore, it exhibited good reproducibility and stability; meanwhile, it also showed excellent specificity due to the specific recognition of antigen by antibody. Therefore, the DNA template synthesized Pd nanoparticles based signal amplification approach has great potential in clinical applications and is also suitable for quantification of biomarkers at ultralow level. - Graphical abstract: A novel label-free and enzyme-free electrochemical immunoassay based on proximity hybridization-regulated catalytic DNA hairpin assemblies for recycling of the CEA. - Highlights: • A novel enzyme-free electrochemical immunosensor was developed for detection of CEA. • The signal amplification was based on catalytic DNA hairpin assembly and DNA-template-synthesized Pd nanoparticles. • The biosensor could detect CEA down to 0.52 × 10 −16  g mL −1 level with a dynamic range spanning 5 orders of magnitude.

Superconducting energy gap of BaPb/sub 1-//sub x/Bi/sub x/O3

International Nuclear Information System (INIS)

Schlesinger, Z.; Collins, R.T.; Scott, B.A.; Calise, J.A.

1988-01-01

We report the first infrared measurement of the superconducting energy gap of BaPb/sub 1-//sub x/Bi/sub x/O 3 . In our polycrystalline samples with T/sub c/≅9.5 K (x≅0.2) we obtain 2Δ≅3.2kT/sub c/, roughly in agreement with the weak-coupling Bardeen-Cooper-Schrieffer prediction, 2Δ = 3.5kT/sub c/, and with tunneling measurements of the gap. We do not observe any structure above the gap energy associated with strong coupling

Surface properties and dye loading behavior of Zn{sub 2}SnO{sub 4} nanoparticles hydrothermally synthesized using different mineralizers

Energy Technology Data Exchange (ETDEWEB)

Annamalai, Alagappan; Eo, Yang Dam [Department of Advanced Technology Fusion, Konkuk University, 1 Hwayang-dong, Kwangjin-gu, Seoul 143-701 (Korea, Republic of); Im, Chan [Department of Chemistry, Konkuk University, 1 Hwayang-dong, Kwangjin-gu, Seoul 143-701 (Korea, Republic of); Lee, Man-Jong, E-mail: leemtx@konkuk.ac.kr [Department of Advanced Technology Fusion, Konkuk University, 1 Hwayang-dong, Kwangjin-gu, Seoul 143-701 (Korea, Republic of)

2011-10-15

We present for the first time the influence of different mineralizers on the isoelectric point (IEP) of zinc stannate (Zn{sub 2}SnO{sub 4}) nanoparticles hydrothermally prepared using three different mineralizers, viz., Na{sub 2}CO{sub 3}, KOH and tert-butyl amine, and the effect of the IEPs on the dye loading behavior of Zn{sub 2}SnO{sub 4} based photoelectrodes in dye sensitized solar cells (DSSCs). To produce highly crystalline, uniform sized Zn{sub 2}SnO{sub 4} nanoparticles, hydrothermal processing parameters, such as reaction temperature, time, and the mineralizers used have been critically adjusted. The structural and morphological features of the as-synthesized Zn{sub 2}SnO{sub 4} nanoparticles have been observed using both scanning and transmission electron microscopy. For the surface state characterization of shape- and size-controlled Zn{sub 2}SnO{sub 4} nanoparticles, the IEPs of Zn{sub 2}SnO{sub 4} surfaces were determined through zeta potential measurements. The IEPs were found to be 5.7, 7.4 and 8.1 for Zn{sub 2}SnO{sub 4} nanoparticles formed using Na{sub 2}CO{sub 3}, KOH and tert-butyl amine, respectively, suggesting that the surface properties of Zn{sub 2}SnO{sub 4} nanoparticles can be manipulated through the choice of the mineralizers used during the hydrothermal reaction. The amount of N719 dye loading on the surfaces of Zn{sub 2}SnO{sub 4} electrodes having different IEPs was also evaluated. It was revealed that the higher the IEP, the higher the dye loading amount, which means that the IEP mainly affects the dye loading at the dye-metal oxide interface. - Highlights: {yields} The effect of various mineralizers on the isoelectric point of Zn{sub 2}SnO{sub 4} was discussed. {yields} The IEP of Zn{sub 2}SnO{sub 4} can be modified by the choice of mineralizer. {yields} Change in IEP affects the surface properties and the morphology of Zn{sub 2}SnO{sub 4} particles. {yields} Modified surface affects the N719 dye loading behaviour of the Zn{sub 2

Atomic-scale microstructural characterization and dielectric properties of crystalline cubic pyrochlore Bi1.5MgNb1.5O7 nanoparticles synthesized by sol-gel method

KAUST Repository

Zhang, Yuan; Zhu, Xinhua; Zhou, Shunhua; Zhu, Jianmin; Liu, Zhiguo; Al-Kassab, Talaat

2013-01-01

Here, we report the atomic-scale microstructural characterization and dielectric properties of crystalline cubic pyrochlore Bi1.5MgNb 1.5O7 (BMN) nanoparticles with mean size of 70 nm, which were synthesized by sol-gel method. The crystallinity, phase formation, morphology, and surface microstructure of the BMN nanoparticles were characterized by X-ray diffraction (XRD), Raman spectra, transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), respectively. The phase evolution of the BMN nanoparticles investigated by XRD patterns showed that uniform cubic pyrochlore BMN nanoparticles were obtained after calcination at temperature of 800 C, and their structural information was revealed by Raman spectrum. TEM images demonstrated that the BMN nanoparticles had a spherical morphology with an average particle size of 70 nm, and their crystalline nature was revealed by HRTEM images. In addition, HRTEM images also demonstrate a terrace-ledge-kink (TLK) surface structure at the edges of rough BMN nanoparticles, where the terrace was on the (100) plane, and the ledge on the (001) plane. The formation of such a TLK surface structure can be well explained by a theory of periodic bond chains. Due to the surface structural reconstruction in the BMN nanoparticles, the formation of a tetragonal structure in a rough BMN nanoparticle was also revealed by HRTEM image. The BMN nanoparticles exhibited dielectric constants of 50 at 100 kHz and 30 at 1 MHz, and the dielectric loss of 0.19 at 1 MHz. © 2013 Springer Science+Business Media Dordrecht.

Atomic-scale microstructural characterization and dielectric properties of crystalline cubic pyrochlore Bi1.5MgNb1.5O7 nanoparticles synthesized by sol-gel method

KAUST Repository

Zhang, Yuan

2013-12-24

Here, we report the atomic-scale microstructural characterization and dielectric properties of crystalline cubic pyrochlore Bi1.5MgNb 1.5O7 (BMN) nanoparticles with mean size of 70 nm, which were synthesized by sol-gel method. The crystallinity, phase formation, morphology, and surface microstructure of the BMN nanoparticles were characterized by X-ray diffraction (XRD), Raman spectra, transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), respectively. The phase evolution of the BMN nanoparticles investigated by XRD patterns showed that uniform cubic pyrochlore BMN nanoparticles were obtained after calcination at temperature of 800 C, and their structural information was revealed by Raman spectrum. TEM images demonstrated that the BMN nanoparticles had a spherical morphology with an average particle size of 70 nm, and their crystalline nature was revealed by HRTEM images. In addition, HRTEM images also demonstrate a terrace-ledge-kink (TLK) surface structure at the edges of rough BMN nanoparticles, where the terrace was on the (100) plane, and the ledge on the (001) plane. The formation of such a TLK surface structure can be well explained by a theory of periodic bond chains. Due to the surface structural reconstruction in the BMN nanoparticles, the formation of a tetragonal structure in a rough BMN nanoparticle was also revealed by HRTEM image. The BMN nanoparticles exhibited dielectric constants of 50 at 100 kHz and 30 at 1 MHz, and the dielectric loss of 0.19 at 1 MHz. © 2013 Springer Science+Business Media Dordrecht.

Structure and functional properties of epitaxial PBZRxTI1-xO3 films

NARCIS (Netherlands)

Vergeer, Kurt

2017-01-01

The work described in this thesis is focused on the characterization and understanding of epitaxial, clamped, dense PbZrxTi1-xO3 (PZT) films. A thermodynamic model is developed, which is used to simulate properties of clamped PZT films throughout this work. The free energy equations for single- and

Magnetic and catalytic properties of inverse spinel CuFe{sub 2}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Anandan, S., E-mail: sanand@nitt.edu [Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620 015 (India); Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan (China); Selvamani, T.; Prasad, G. Guru [Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620 015 (India); Asiri, A.M. [The Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21413 (Saudi Arabia); Wu, J.J., E-mail: jjwu@fcu.edu.tw [Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan (China)

2017-06-15

Highlights: • Copper ferrite (CuFe{sub 2}O{sub 4}) nanoparticles were synthesized via citrate-nitrate combustion method. • Spectroscopic information’s have found that CuFe{sub 2}O{sub 4} nanoparticles as an inverse spinel structure. • Magnetic study exhibits CuFe{sub 2}O{sub 4} nanoparticles have ferromagnetic behavior. • CuFe{sub 2}O{sub 4} nanoparticles employed for photocatalytic decolourisation of methylene blue under visible light irradiation. - Abstract: In this research, inverse spinel copper ferrite nanoparticles (CuFe{sub 2}O{sub 4} NPs) were synthesized via citrate-nitrate combustion method. The crystal structure, particle size, morphology and magnetic studies were investigated using various instrumental tools to illustrate the formation of the inverse spinel structure. Mossbauer spectrometry identified Fe is located both in the tetrahedral and octahedral site in the ratio (40:60) and the observed magnetic parameters values such as saturation magnetization (M{sub s} = 20.62 emu g{sup −1}), remnant magnetization (M{sub r} = 11.66 emu g{sup −1}) and coercivity (H{sub c} = 63.1 mTesla) revealed that the synthesized CuFe{sub 2}O{sub 4} NPs have a typical ferromagnetic behaviour. Also tested CuFe{sub 2}O{sub 4} nanoparticles as a photocatalyst for the decolourisation of methylene blue (MB) in the presence of peroxydisulphate as the oxidant.

Optical and structure characterization of cinnamon nanoparticles synthesized by pulse laser ablation in liquid (PLAL)

Science.gov (United States)

Aqeel Salim, Ali; Bidin, Noriah; Bakhtiar, Hazri; Krishna Ghoshal, Sib; Azawi, Mohammed Al; Krishnan, Ganesan

2018-05-01

Organic nanoparticles development is under exploration due to its beneficial applications in nanobiomedical and research interests. PLAL technique of Q-switched 1064-Nd: YAG (10 ns pulse duration, repetition rate 1 Hz and laser energy 20-100 mJ) has inherent advantages and rapid growth of nanoparticles when compared to conventional methods because of the controlled fabricated nanoparticles, stability, and purity. Cinnamon sticks as a target are immersed in 5 ml ethanol medium and irradiated by a laser beam for the growth process. The morphology, optical characteristic, and bonding structure of cinnamon nanoparticles (CNPs) are determined and evaluated by transmission electron microscope (TEM), UV-Visible spectroscopy and Fourier transform infrared spectroscopy (FTIR). Spherical, homogenous and high crystallinity CNPs was revealed within the particle size range of 2 - 28 nm. The absorption band was found in the ultraviolent region around 259 nm and 319 nm. The present of FTIR spectra confirmed that the nanoparticles were covered by plant secondary metabolites. The experimental findings revealed that the synthesize CNPs in ethanol has a potential for nanomedicine applications.

PEG capped CaS nanoparticles synthesized by wet chemical co-precipitation method

Science.gov (United States)

Rekha, S.; Anila, E. I.

2018-04-01

Calcium sulfide (CaS) nanoparticles capped with polyethyleneglycol (PEG) were synthesized using wet chemical co-precipitation method. The structural and optical properties of the prepared sample were studied by X-ray diffractogram (XRD), transmission electron microscopy (TEM), diffuse reflectance spectrum (DRS) and photoluminescence (PL) spectrum. The structure of CaS nanoparticles is cubic as demonstrated by the X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) analysis. TEMimage revealed the spherical morphology of the particles with diameter in the range 15-20 nm. The optical band gap of the prepared sample was determined from the DRS and its value was found to be 4.1 eV. The PL studies showed that the relative intensity of the PEG capped CaS nanoparticles was higher than that of uncapped CaS nanoparticles. The presence of various functional groups in the capped samples were examined by Fourier Transform Infrared (FTIR) spectroscopy.

Composition and hydrophilicity control of Mn-doped ferrite (MnxFe3-xO4) nanoparticles induced by polyol differentiation.

Science.gov (United States)

Vamvakidis, Kosmas; Katsikini, Maria; Vourlias, George; Angelakeris, Mavroeidis; Paloura, Eleni C; Dendrinou-Samara, Catherine

2015-03-28

Manganese doped ferrite (MnxFe3-xO4) nanoparticles with x = 0.29-0.77 were prepared under solvothermal conditions in the presence solely of a polyol using the trivalent manganese and iron acetylacetonates as precursors. In this facile approach, a variety of polyols such as polyethylene glycol (PEG 8000), tetraethylene glycol (TEG), propylene glycol (PG) and a mixture of TEG and PG (1 : 1) were utilized in a triple role as a solvent, a reducing agent and a surface-functionalizing agent. The composition of the fine cubic-spinel structures was found to be related to the reductive ability of each polyol, while determination of structural characteristics plus the inversion parameter (i = 0.18-0.38) were provided by X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy at both the Fe and Mn K-edges. The saturation magnetization increased up to 80 emu g(-1) when x = 0.35 and i = 0.22. In addition, the as-prepared nanocrystals coated with PEG, PG and PG&TEG showed excellent colloidal stability in water, while the TEG-coated particles were not water dispersible and converted to hydrophilic when were extra PEGylated. Measurements of the (1)H NMR relaxation in water were carried out and the nanoprobes were evaluated as potential contrast agents.

Composition tunable cobalt–nickel and cobalt–iron alloy nanoparticles below 10 nm synthesized using acetonated cobalt carbonyl

International Nuclear Information System (INIS)

Schooneveld, Matti M. van; Campos-Cuerva, Carlos; Pet, Jeroen; Meeldijk, Johannes D.; Rijssel, Jos van; Meijerink, Andries; Erné, Ben H.; Groot, Frank M. F. de

2012-01-01

A general organometallic route has been developed to synthesize Co x Ni 1−x and Co x Fe 1−x alloy nanoparticles with a fully tunable composition and a size of 4–10 nm with high yield. In contrast to previously reported synthesis methods using dicobalt octacarbonyl (Co 2 (CO) 8 ), here the cobalt–cobalt bond in the carbonyl complex is first broken with anhydrous acetone. The acetonated compound, in the presence of iron carbonyl or nickel acetylacetonate, is necessary to obtain small composition tunable alloys. This new route and insights will provide guidelines for the wet-chemical synthesis of yet unmade bimetallic alloy nanoparticles.

Magnetorheology of colloidal dispersion containing Fe nanoparticles synthesized by the arc-plasma method

International Nuclear Information System (INIS)

Noma, Junichi; Abe, Hiroya; Kikuchi, Takehito; Furusho, Junji; Naito, Makio

2010-01-01

Spherical crystalline Fe nanoparticles, ∼100 nm in diameter, were synthesized under Ar-50% H 2 arc-plasma. These nanoparticles were dispersed in silicone oil after silane treatment on as-grown thin oxide layer (∼2 nm) to make their surfaces hydrophobic. The resulting Fe nanoparticles exhibited a high saturation magnetization of ∼190 emu/g at room temperature. The static magnetorheological behavior was measured for the colloidal dispersion (solid concentration: 15 vol%) at room temperature under magnetic flux densities of 0-0.3 T, using a parallel-plate-type commercial rheometer. The yield stress continuously increased with magnetic flux density, demonstrating the Bingham plastic behavior. Moreover, subjecting the sample to a magnetic flux density of 0.3 T increased the yield stress by ∼10 2 . Additionally, the colloidal dispersion exhibited good stability against sedimentation.

Magnetorheology of colloidal dispersion containing Fe nanoparticles synthesized by the arc-plasma method

Science.gov (United States)

Noma, Junichi; Abe, Hiroya; Kikuchi, Takehito; Furusho, Junji; Naito, Makio

2010-07-01

Spherical crystalline Fe nanoparticles, ˜100 nm in diameter, were synthesized under Ar-50% H 2 arc-plasma. These nanoparticles were dispersed in silicone oil after silane treatment on as-grown thin oxide layer (˜2 nm) to make their surfaces hydrophobic. The resulting Fe nanoparticles exhibited a high saturation magnetization of ˜190 emu/g at room temperature. The static magnetorheological behavior was measured for the colloidal dispersion (solid concentration: 15 vol%) at room temperature under magnetic flux densities of 0-0.3 T, using a parallel-plate-type commercial rheometer. The yield stress continuously increased with magnetic flux density, demonstrating the Bingham plastic behavior. Moreover, subjecting the sample to a magnetic flux density of 0.3 T increased the yield stress by ˜10 2. Additionally, the colloidal dispersion exhibited good stability against sedimentation.

Enhanced antibacterial activity of zinc oxide nanoparticles synthesized using Petroselinum crispum extracts

Energy Technology Data Exchange (ETDEWEB)

Stan, Manuela, E-mail: manuela.stan@itim-cj.ro; Popa, Adriana; Toloman, Dana; Silipas, Teofil-Danut [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, 400293 Cluj-Napoca (Romania); Vodnar, Dan Cristian [University of Agricultural Sciences and Veterinary Medicine, Department of Food Science and Technology, 3-5 Manastur Street, 400372 Cluj-Napoca (Romania); Katona, Gabriel [Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, 400028 Cluj-Napoca (Romania)

2015-12-23

The present contribution reports the synthesis of zinc oxide nanoparticles (ZnO NPs) using aqueous leaf and root extracts of Petroselinum crispum (parsley) and characterization of as-prepared samples. ZnO NPs are subjected to X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) studies. The XRD studies reveal a hexagonal wurtzite structure without supplementary diffraction lines for all ZnO samples. TEM analysis shows that the particle size is influenced by the type of plant extract. The EPR spectra indicate the presence of Mn{sup 2+} ions in ZnO sample synthesized using P. crispum leaf extract, while zinc vacancy complexes and oxygen vacancies are evidenced in all analyzed samples. ZnO NPs synthesized using P. crispum extracts exhibit increased (2-16 times) antibacterial activity as compared to chemically synthesized ZnO NPs.

Enhanced antibacterial activity of zinc oxide nanoparticles synthesized using Petroselinum crispum extracts

International Nuclear Information System (INIS)

Stan, Manuela; Popa, Adriana; Toloman, Dana; Silipas, Teofil-Danut; Vodnar, Dan Cristian; Katona, Gabriel

2015-01-01

The present contribution reports the synthesis of zinc oxide nanoparticles (ZnO NPs) using aqueous leaf and root extracts of Petroselinum crispum (parsley) and characterization of as-prepared samples. ZnO NPs are subjected to X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) studies. The XRD studies reveal a hexagonal wurtzite structure without supplementary diffraction lines for all ZnO samples. TEM analysis shows that the particle size is influenced by the type of plant extract. The EPR spectra indicate the presence of Mn 2+ ions in ZnO sample synthesized using P. crispum leaf extract, while zinc vacancy complexes and oxygen vacancies are evidenced in all analyzed samples. ZnO NPs synthesized using P. crispum extracts exhibit increased (2-16 times) antibacterial activity as compared to chemically synthesized ZnO NPs

Gel-combustion-synthesized ZnO nanoparticles for visible light ...

Indian Academy of Sciences (India)

Zinc oxide nanoparticles (ZnO NPs) synthesized by the gel combustion technique using a bio-fuel, cassava starch (root tubers of Manihot esculenta), have been characterized by various techniques. The X-ray diffractionpattern reveals hexagonal wurtzite structure. The particle size averaged around 45nm with an excellent ...

A Study On Dispersion Stability Of Nickel Nanoparticles Synthesized By Wire Explosion In Liquid Media

Directory of Open Access Journals (Sweden)

Kim C.K.

2015-06-01

Full Text Available In this study, nickel nanoparticles were synthesized in ethanol using portable pulsed wire evaporation, which is a one-step physical method. From transmission electron microscopy images, it was found that the Ni nanoparticles exhibited a spherical shape with an average diameter of 7.3 nm. To prevent aggregation of the nickel nanoparticles, a polymer surfactant was added into the ethanol before the synthesis of nickel nanoparticles, and adsorbed on the freshly synthesized nickel nanoparticles during the wire explosion. The dispersion stability of the prepared nickel nanofluids was investigated by zeta-potential analyzer and Turbiscan optical analyzer. As a result, the optimum concentration of polymer surfactant to be added was suggested for the maximized dispersion stability of the nickel nanofluids.

Evaluation of superparamagnetic and biocompatible properties of mesoporous silica coated cobalt ferrite nanoparticles synthesized via microwave modified Pechini method

Energy Technology Data Exchange (ETDEWEB)

Gharibshahian, M. [Faculty of New Sciences and Technologies, Semnan University, Semnan (Iran, Islamic Republic of); Mirzaee, O., E-mail: O_mirzaee@semnan.ac.ir [Faculty of Materials and Metallurgical Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Nourbakhsh, M.S. [Faculty of New Sciences and Technologies, Semnan University, Semnan (Iran, Islamic Republic of)

2017-03-01

Cobalt ferrite nano particles were synthesized by Pechini sol-gel method and calcined at 700 °C in electrical and microwave furnace. The microwave calcined sample was coated with mesoporous silica by hydrothermal method. Characterization was performed by XRD, FESEM, TEM, VSM, BET and FTIR analysis. The cytotoxicity was evaluated by MTT assay with 3T3 fibroblast cells. The XRD and FTIR results confirmed spinal formation in both cases and verified the formation of silica coating on the nanoparticles. For microwave calcination, The XRD and SEM results demonstrated smaller and flat adhesion forms of nanoparticles with the average size of 15 nm. The VSM results demonstrated nearly superparamagnetic nanoparticles with significant saturation magnetization equal to 64 emu/g. By coating, saturation magnetization was decreased to 36 emu/g. Moreover, the BET results confirmed the formation of mesoporous coating with the average pore diameters of 2.8 nm and average pore volume of 0.82 cm{sup 3} g{sup −1}. Microwave calcined nanoparticles had the best structural and magnetic properties. - Highlights: • CoFe{sub 2}O{sub 4} nanoparticles were synthesized using the microwave modified Pechini method. • The Effect of calcination route and silica coating on NPs properties was studied. • The nearly superparamagnetic nanoparticles were achieved by microwave calcination. • MFC NPs had the best magnetic properties and MTT assay showed no toxicity for MFC-MSC NPs. • A useful scheme was designed to achieve biological superparamagnetic core/shell NPs.

A facile route to synthesize nanogels doped with silver nanoparticles

Science.gov (United States)

Coll Ferrer, M. Carme; Ferrier, Robert C.; Eckmann, David M.; Composto, Russell J.

2013-01-01

In this study, we describe a simple method to prepare hybrid nanogels consisting of a biocompatible core-shell polymer host containing silver nanoparticles. First, the nanogels (NG, 160 nm) containing a lysozyme rich core and a dextran rich shell, are prepared via Maillard and heat-gelation reactions. Second, silver nanoparticles (Ag NPs, 5 nm) are synthesized "in situ" in the NG solution without requiring additional reducing agents. This approach leads to stable Ag NPs located in the NG. Furthermore, we demonstrate that the amount of Ag NPs in the NG can be tuned by varying silver precursor concentration. Hybrid nanogels with silver nanoparticles have potential in antimicrobial, optical, and therapeutic applications.

Improved Catalysis of Green-Synthesized Pd-Ag Alloy-Nanoparticles for Anodic Oxidation of Methanol in Alkali

International Nuclear Information System (INIS)

Roy Chowdhury, Sreya; Ghosh, Srabanti; Bhattachrya, Swapan Kumar

2017-01-01

Highlights: • Pd and Pd x Ag y nanoalloys are synthesised by simple green synthetic method without using any capping agent. • Increased electrochemical surface area and roughness factor in case of Pd x Ag y alloy generates enhanced catalytically active sites which help methanol oxidation reaction. • By analysing the products of MOR reaction by CV, FTIR and HPLC plausible mechanism of the reaction is proposed. • Among different compositions Pd 4 Ag and Pd are the best electrodes for oxidation of methanol and formate respectively in alkali. - Abstract: Monometallic Pd, Ag and bimetallic Pd x Ag y alloy nanoparticles were synthesized in a single pot using a green synthetic protocol in absence of any capping agent. X-ray, electron diffraction, microscopic and spectroscopic studies of synthesized material demonstrate the formation of nanoballs with radius of 10–20 nm of face centred cubic metals and alloys. The electrochemical studies of as-synthesized materials loaded on carbon support reveal that the Pd 4 Ag nanoparticles exhibit the best and synergistic electro-catalytic activity in reference to oxidation of methanol in alkali. The most active Pd 4 Ag nanoparticles show higher peak current (201 mA mg −1 ) in comparison to that (133 mA mg −1 ) of Pd in cyclic voltammetric study. The electrode shows the highest exchange current density (1.95 × 10 −2 mA mg −1 of Pd) for methanol oxidation reaction (MOR) and higher catalytic activity for oxidation of possible intermediates like formaldehyde and sodium formate of MOR. Ex-situ infrared spectrometry and chromatographic studies of reaction products reveal that Ag accelerates the formation of formate rather than carbonate elucidating the plausible mechanism of the reaction. These findings have important implications for further fine-tuning of the Pd nano alloys toward highly active and selective catalysts for alcohol fuel cells.

Potassium-doped copper oxide nanoparticles synthesized by a solvothermal method as an anode material for high-performance lithium ion secondary battery

Energy Technology Data Exchange (ETDEWEB)

Thi, Trang Vu; Rai, Alok Kumar; Gim, Jihyeon; Kim, Jaekook, E-mail: jaekook@chonnam.ac.kr

2014-06-01

A simple and efficient approach was developed to synthesize CuO nanoparticles with improved electrochemical performance. Potassium (K{sup +})-doped CuO nanoparticles were synthesized by a simple and cost-effective solvothermal method followed by annealing at 500 °C for 5 h under air atmosphere. For comparison, an undoped CuO sample was also synthesized under the same conditions. X-ray diffraction analysis demonstrates that the K{sup +} ion doping caused no change in the phase structure, and highly crystalline K{sub x}Cu{sub 1−x}O{sub 1−δ} (x = 0.10) powder without any impurity was obtained. As an anode material for a lithium ion battery, the K{sup +}-doped CuO nanoparticle electrode exhibited better capacity retention with a reversible capacity of over 354.6 mA h g{sup −1} for up to 30 cycles at 0.1 C, as well as a high charge capacity of 162.3 mA h g{sup −1} at a high current rate of 3.2 C, in comparison to an undoped CuO electrode (275.9 mA h g{sup −1} at 0.1 C and 68.9 mA h g{sup −1} at 3.2 C). The high rate capability and better cycleability of the doped electrode can be attributed to the influence of the K{sup +} ion nanostructure on the increased electronic conductivity, diffusion efficiency, and kinetic properties of CuO during the lithiation and delithiation process.

Direct formation of new, phase-stable, and photoactive anatase-type Ti1-2XNbXScXO2 solid solution nanoparticles by hydrothermal method

International Nuclear Information System (INIS)

Hirano, Masanori; Ito, Takaharu

2008-01-01

A new anatase phase of photoactive Ti 1-2X Nb X Sc X O 2 (X = 0-0.2) solid solutions was directly formed as nanoparticles from precursor solutions of TiOSO 4 , NbCl 5 , and Sc(NO 3 ) 3 under mild hydrothermal conditions at 180 deg. C for 5 h using the hydrolysis of urea. With the increase of the content of niobium and scandium from X = 0 to 0.2, the lattice parameters a 0 and c 0 , the crystallite size, and the optical band gap of anatase gradually increased. Their photocatalytic activity and adsorptivity were evaluated separately by the measurement of the concentration of methylene blue (MB) remained in the solution in the dark or under UV-light irradiation. The anatase-type Ti 1-2X Nb X Sc X O 2 (X = 0.05) showed approximately two times and three times as high photocatalytic activity as those of the hydrothermal anatase-type pure TiO 2 and commercially available reference pure TiO 2 (ST-01), respectively. The anatase phase of Ti 1-2X Nb X Sc X O 2 (X = 0-0.2) existed stably up to 900 deg. C during heat treatment in air. New rutile-type Ti 1-2X Nb X Sc X O 2 solid solutions are formed through the phase transformation. The starting temperature of anatase-to-rutile phase transformation for Ti 1-2X Nb X Sc X O 2 (X = 0-0.2) solid solutions was delayed but its completing temperature was accelerated

Purification of simulated waste water using green synthesized silver nanoparticles of Piliostigma thonningii aqueous leave extract

Science.gov (United States)

Shittu, K. O.; Ihebunna, O.

2017-12-01

Synthesis of nanoparticles from various biological systems has been reported, but among all such systems, biosynthesis of nanoparticles from plants is considered the most suitable method. The use of plant material not only makes the process eco-friendly, but also the abundance makes it more economical. The aim of this study was to biologically synthesize silver nanoparticle using Piliostigma thonningii aqueous leaf extract and applied in the purification of laboratory stimulated waste with optimization using the different conditions of silver nanoparticle production such as time, temperature, pH, concentration of silver nitrate and volume of the aqueous extract. The biosynthesized silver nanoparticles were characterized by UV-visible spectrophotometry, nanosizer, energy dispersive x-ray analysis (EDX), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The time intervals for the reaction with aqueous silver nitrate solution shows an increase in the absorbance with time and became constant giving a maximum absorbance at 415 nm at 60 min of incubation. The pH of 6.5, temperature 65 °C, 1.25 mM of silver nitrate and 5 ml of plant extract was the best condition with maximum absorbance. The results from nanosizer, UV-vis and TEM suggested the biosynthesis silver nanoparticle to be spherical ranging from 50 nm to 114 nm. The EDX confirmed the elemental synthesis of silver at 2.60 keV and FTIR suggested the capping agent to be hydroxyl (OH) group with -C=C stretching vibrations. The synthesized silver nanoparticle also shows heavy metal removal activity in laboratory simulated waste water. The safety toxicity studies show no significant difference between the orally administered silver nanoparticles treated water group and control group, while the histopathological studies show well preserved hepatic architecture for the orally administered silver nanoparticle treated waste water group when compared with the control

Small-angle neutron scattering investigations of Co-doped iron oxide nanoparticles. Preliminary results

Science.gov (United States)

Creanga, Dorina; Balasoiu, Maria; Soloviov, Dmitro; Balasoiu-Gaina, Alexandra-Maria; Puscasu, Emil; Lupu, Nicoleta; Stan, Cristina

2018-03-01

Preliminary small-angle neutron scattering investigations on aqueous suspensions of several cobalt doped ferrites (CoxFe3-xO4, x=0; 0.5; 1) nanoparticles prepared by chemical co-precipitation method, are reported. The measurements were accomplished at the YuMO instrument in function at the IBR-2 reactor. Results of intermediary data treatment are presented and discussed.

1-Hexadecylamine as both reducing agent and stabilizer to synthesize Au and Ag nanoparticles and their SERS application

International Nuclear Information System (INIS)

Hou Xiaomiao; Zhan, Xiaoling; Fang Yan; Chen Shutang; Li Na; Zhou Qi

2011-01-01

1-Hexadecylamine (HDA)-capped Au and Ag nanoparticles (NPs) have been successfully prepared by a one-pot solution growth method. The HDA is used as both reducing agent and stabilizer in the synthetic process is favorable for investigating the capping mechanism of Au and Ag NPs’ surface. The growth process and characterization of Au and Ag NPs are determined by Ultraviolet–visible (UV–vis) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD). Experimental results demonstrate that the HDA-capped Au and Ag NPs are highly crystalline and have good optical properties. Furthermore, surface-enhanced Raman scattering (SERS) spectra of 2-thionaphthol are obtained on the Au and Ag NPs modified glass surface, respectively, indicating that the as-synthesized noble metal NPs have potentially high sensitive optical detection application.

1-Hexadecylamine as both reducing agent and stabilizer to synthesize Au and Ag nanoparticles and their SERS application

Energy Technology Data Exchange (ETDEWEB)

Hou Xiaomiao; Zhan, Xiaoling, E-mail: zhangxl@bit.edu.cn [Beijing Institute of Technology, Department of Chemistry, School of Science (China); Fang Yan, E-mail: fangyan@mail.cnu.edu.cn [Capital Normal University, Beijing Key Lab for Nano-Photonics and Nano-Structure (NPNS), Department of Physics (China); Chen Shutang; Li Na; Zhou Qi [Beijing Institute of Technology, Department of Chemistry, School of Science (China)

2011-05-15

1-Hexadecylamine (HDA)-capped Au and Ag nanoparticles (NPs) have been successfully prepared by a one-pot solution growth method. The HDA is used as both reducing agent and stabilizer in the synthetic process is favorable for investigating the capping mechanism of Au and Ag NPs' surface. The growth process and characterization of Au and Ag NPs are determined by Ultraviolet-visible (UV-vis) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD). Experimental results demonstrate that the HDA-capped Au and Ag NPs are highly crystalline and have good optical properties. Furthermore, surface-enhanced Raman scattering (SERS) spectra of 2-thionaphthol are obtained on the Au and Ag NPs modified glass surface, respectively, indicating that the as-synthesized noble metal NPs have potentially high sensitive optical detection application.

Coercivity enhancement mechanism in Dy-substituted Nd–Fe–B nanoparticles synthesized by sol–gel base method followed by a reduction-diffusion process

Energy Technology Data Exchange (ETDEWEB)

Rahimi, Hamed; Ghasemi, Ali, E-mail: ali13912001@yahoo.com; Mozaffarinia, Reza; Tavoosi, Majid

2017-05-01

In current work, Nd{sub 15−x}Dy{sub x}Fe{sub 77.5}B{sub 7.5} (at%) nanoparticles with different Dy-content (x=0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0) were synthesized by sol–gel method followed by a reduction-diffusion process. The effects of Dy on the magnetic properties and the relations between the microstructure and the coercivity of Dy-substituted Nd–Fe–B nanoparticles have been studied. The coercivity of Nd–Fe–B nanoparticles with the addition of Dy first increase, reaches a maximum, and then starts to decrease. The coercivity of Dy-substituted Nd–Fe–B nanoparticle synthesized by sol–gel method increased from 938.9 to 1663.9 kA/m while the remanence decreased slightly from 1.16 to 1.06 T. The results show that with an increase in Dy content the variation of maximum energy product ((BH){sub max}), lowest-order uniaxial magnetocrystalline anisotropy constant (K{sub u1}), and Curie temperature (T{sub c}) had a trend as same as the coercivity. The Henkel plot showed that the existence of exchange coupling interaction between grains, and the exchange coupling interactions increased with increasing x from 0.0 to 2.0 and then decrease with further increasing x≥2.5. The optimum magnetic properties of Nd–Fe–B nanoparticles with (BH){sub max} =40.38 MGOe, H{sub c}=1663.9 kA/m, B{sub r}=1.08 T were obtained by substituted 2.0 at% Dy. The effects of increasing temperature on magnetic properties of Dy-substituted Nd–Fe–B nanoparticle magnets with 2.0 at% Dy was investigated. The reduced spin-reorientation temperature was obtained for Dy-substituted Nd–Fe–B nanoparticles with 2.0 at% Dy. Below 100 K a spin-reorientation transition was takes place. The temperature coefficient of coercivity (β) was −0.36, −0.46, −0.41, −0.34, −0.29, −0.24, −0.25%/°C at different temperature 50, 100, 150, 200, 250, 300, 350 °C, respectively. Mössbauer spectroscopy was applied to study the composition and properties of Dy-substituted Nd�

Coercivity enhancement mechanism in Dy-substituted Nd–Fe–B nanoparticles synthesized by sol–gel base method followed by a reduction-diffusion process

International Nuclear Information System (INIS)

Rahimi, Hamed; Ghasemi, Ali; Mozaffarinia, Reza; Tavoosi, Majid

2017-01-01

In current work, Nd 15−x Dy x Fe 77.5 B 7.5 (at%) nanoparticles with different Dy-content (x=0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0) were synthesized by sol–gel method followed by a reduction-diffusion process. The effects of Dy on the magnetic properties and the relations between the microstructure and the coercivity of Dy-substituted Nd–Fe–B nanoparticles have been studied. The coercivity of Nd–Fe–B nanoparticles with the addition of Dy first increase, reaches a maximum, and then starts to decrease. The coercivity of Dy-substituted Nd–Fe–B nanoparticle synthesized by sol–gel method increased from 938.9 to 1663.9 kA/m while the remanence decreased slightly from 1.16 to 1.06 T. The results show that with an increase in Dy content the variation of maximum energy product ((BH) max ), lowest-order uniaxial magnetocrystalline anisotropy constant (K u1 ), and Curie temperature (T c ) had a trend as same as the coercivity. The Henkel plot showed that the existence of exchange coupling interaction between grains, and the exchange coupling interactions increased with increasing x from 0.0 to 2.0 and then decrease with further increasing x≥2.5. The optimum magnetic properties of Nd–Fe–B nanoparticles with (BH) max =40.38 MGOe, H c =1663.9 kA/m, B r =1.08 T were obtained by substituted 2.0 at% Dy. The effects of increasing temperature on magnetic properties of Dy-substituted Nd–Fe–B nanoparticle magnets with 2.0 at% Dy was investigated. The reduced spin-reorientation temperature was obtained for Dy-substituted Nd–Fe–B nanoparticles with 2.0 at% Dy. Below 100 K a spin-reorientation transition was takes place. The temperature coefficient of coercivity (β) was −0.36, −0.46, −0.41, −0.34, −0.29, −0.24, −0.25%/°C at different temperature 50, 100, 150, 200, 250, 300, 350 °C, respectively. Mössbauer spectroscopy was applied to study the composition and properties of Dy-substituted Nd–Fe–B magnet. Microstructure analysis showed a

Antimicrobial Activities of Silver Nanoparticles Synthesized by Using Water Extract of Arnicae anthodium.

Science.gov (United States)

Dobrucka, Renata; Długaszewska, Jolanta

2015-06-01

Green synthesis of nanoparticles has gained significant importance in recent years and has become the one of the most preferred methods. Also, green synthesis of nanoparticles is valuable branch of nanotechnology. Plant extracts are eco-friendly and can be an economic option for synthesis of nanoparticles. This study presents method the synthesis of silver nanoparticles using water extract of Arnicae anthodium. Formation of silver nanoparticles was confirmed by UV-visble spectroscopy, Fourier transform infrared spectroscopy and total reflection X-ray fluorescence analysis. The morphology of the synthesized silver nanoparticles was verified by SEM-EDS. The obtained silver nanoparticles were used to study their antimicrobial activity.

Structure and Plasmonic Properties of Thin PMMA Layers with Ion-Synthesized Ag Nanoparticles

DEFF Research Database (Denmark)

Popok, Vladimir; Hanif, Muhammad; Mackova, Anna

2015-01-01

nanoparticles above the surface. The synthesized nanoparticles can be split into two groups: (i) located at the surface and (ii) fully embedded in the shallow layer. These two groups provide corresponding spectral bands related to localized surface plasmon resonance. The bands demonstrate considerable intensity...

TiO2 film decorated with highly dispersed polyoxometalate nanoparticles synthesized by micelle directed method for the efficiency enhancement of dye-sensitized solar cells

Science.gov (United States)

He, Lifei; Chen, Li; Zhao, Yue; Chen, Weilin; Shan, Chunhui; Su, Zhongmin; Wang, Enbo

2016-10-01

In this work, two kinds of polyoxometalate (POM) nanoparticles with controlled shapes and structures were synthesized by micelle directed method and then composited with TiO2 via calcination to remove the surfactants owing to the excellent electronic storage and transmission ability of POM, finally obtaining two kinds of TiO2 composites with highly dispersed and small-sized POM nanoparticles (∼1 nm). The TiO2 composites were then induced into the photoanodes of dye-sensitized (N719) solar cells (DSSCs). The separation of electron-holes becomes more favorable due to the nanostructure and high dispersion of POM which provide more active sites than pure POM tending to agglomeration. The TiO2 composite photoanodes finally yielded the power conversion efficiency (PCE) of 8.4% and 8.2%, respectively, which were 42% and 39% higher than the pristine TiO2 based anodes. In addition, the mechanisms of POM in DSSC are proposed.

Asymmetric dumbbell-shaped silver nanoparticles and spherical gold nanoparticles green-synthesized by mangosteen (Garcinia mangostana) pericarp waste extracts

Science.gov (United States)

Park, Ji Su; Ahn, Eun-Young; Park, Youmie

2017-01-01

Mangosteen (Garcinia mangostana) pericarp waste extract was used to synthesize gold and silver nanoparticles by a green strategy. The extract was both a reducing and stabilizing agent during synthesis. Phytochemical screening of the extract was conducted to obtain information regarding the presence/absence of primary and secondary metabolites in the extract. The in vitro antioxidant activity results demonstrated that the extract had excellent antioxidant activity, which was comparable to a standard (butylated hydroxy toluene). Spherical gold nanoparticles (gold nanoparticles green synthesized by mangosteen pericarp extract [GM-AuNPs]) with an average size of 15.37±3.99 to 44.20±16.99 nm were observed in high-resolution transmission electron microscopy (HR-TEM) images. Most interestingly, the silver nanoparticles (silver nanoparticles green synthesized by mangosteen pericarp extract [GM-AgNPs]) had asymmetric nanodumbbell shapes where one tail grew from a spherical head. The average head size was measured to be 13.65±5.07 to 31.08±3.99 nm from HR-TEM images. The hydrodynamic size of both nanoparticles tended to increase with increasing extract concentration. Large negative zeta potentials (−18.92 to −34.77 mV) suggested that each nanoparticle solution possessed excellent colloidal stability. The reaction yields were 99.7% for GM-AuNPs and 82.8% for GM-AgNPs, which were assessed by inductively coupled plasma optical emission spectroscopy. A high-resolution X-ray diffraction pattern confirmed the face-centered cubic structure of both nanoparticles. Based on phytochemical screening and Fourier transform infrared spectra, the hydroxyl functional groups of carbohydrates, flavonoids, glycosides, and phenolic compounds were most likely involved in a reduction reaction of gold or silver salts to their corresponding nanoparticles. The in vitro cytotoxicity (based on a water-soluble tetrazolium assay) demonstrated that GM-AgNPs were toxic to both A549 (a human lung

Optical and Luminescence Properties of β-NaFeO2 Nanoparticles

Science.gov (United States)

Singh, Sarbjit; Tangra, Ankush Kumar; Lotey, Gurmeet Singh

2018-05-01

β-NaFeO2 nanoparticles have been synthesized by sol-gel method and their morphological, structural and optical properties investigated. Transmission electron microscope study reveals that the size of the synthesis nanoparticles is 37 nm and they are possessing spherical symmetry. X-ray diffraction pattern shows the orthorhombic crystal structure of nanoparticles with space group Pn21 a. UV-visible spectra of β-NaFeO2 divulges that these nanoparticles have direct band gap 2.35 eV. The observed Fourier transform infrared spectroscopy spectra confirms the presence of Fe-Na bonding at 1074 cm-1. The photoluminescence study of these nanoparticles shows that these nanoparticles possesses various transition in the visible spectrum.

Microstructure, morphology and magnetic properties of Ni nanoparticles synthesized by hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Bouremana, A. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria); Guittoum, A., E-mail: aguittoum@gmail.com [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Hemmous, M. [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Martínez-Blanco, D. [SCTs, University of Oviedo, EPM, 33600 Mieres (Spain); Gorria, Pedro [Department of Physics & IUTA, EPI, University of Oviedo, 33203 Gijón (Spain); Blanco, J.A. [Department of Physics, University of Oviedo, Calvo Sotelo St., 33007 Oviedo (Spain); Benrekaa, N. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria)

2015-06-15

Powder samples containing high purity nickel nanoparticles (NPs) were prepared by hydrothermal method from Ni(II) chloride hexahydrate (NiCl{sub 2}·6H{sub 2}O) under the presence of sodium hydroxide (NaOH) with different concentrations between 5 and 25 mol/L. The synthesis of the NPs occurs through chemical reduction at relatively low temperature (140 °C). The Ni NPs have a face-centred cubic (fcc) crystal structure with a lattice parameter value close to that of pure Ni (a = 3.52 Å). The average crystallite size determined from x-ray diffraction is around 20 nm, except for the sample synthesized under the highest NaOH concentration (25 mol/L), which has the largest average size (>30 nm). The powder morphology at the sub-micrometre length scale looks like agglomerates of Ni-NPs that drastically changes their shape depending on the NaOH concentration, from flower (5 mol/L) to a dendritic-like (25 mol/L). All the samples are ferromagnetic at room temperature with saturation magnetization values between 50 and 52emu/g, and a coercive field that increases with the NaOH concentration from around 135 (5 mol/L) up to 180Oe (25 mol/L). - Highlights: • Pure Nickel nanoparticles have been synthesized by a chemical reaction process. • Different morphologies were observed with the change of NaOH concentration. • The coercive field increases with increasing the NaOH concentration and depends on the shape of nanoparticles.

Proximity hybridization-regulated catalytic DNA hairpin assembly for electrochemical immunoassay based on in situ DNA template-synthesized Pd nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Zhou, Fuyi [School of Chemistry and Chemical Engineering, Jiangsu Normal University, Xuzhou 221116 (China); Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical College, 221004, Xuzhou (China); Yao, Yao; Luo, Jianjun; Zhang, Xing; Zhang, Yu; Yin, Dengyang [Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical College, 221004, Xuzhou (China); Gao, Fenglei, E-mail: jsxzgfl@sina.com [Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical College, 221004, Xuzhou (China); Wang, Po, E-mail: wangpo@jsnu.edu.cn [School of Chemistry and Chemical Engineering, Jiangsu Normal University, Xuzhou 221116 (China)

2017-05-29

Novel hybridization proximity-regulated catalytic DNA hairpin assembly strategy has been proposed for electrochemical immunoassay based on in situ DNA template-synthesized Pd nanoparticles as signal label. The DNA template-synthesized Pd nanoparticles were characterized with atomic force microscopic and X-ray photoelectron spectroscopy. The highly efficient electrocatalysis by DNA template synthesized Pd nanoparticles for NaBH{sub 4} oxidation produced an intense detection signal. The label-free electrochemical method achieved the detection of carcinoembryonic antigen (CEA) with a linear range from 10{sup −15} to 10{sup −11} g mL{sup −1} and a detection limit of 0.43 × 10{sup −15} g mL{sup −1}. Through introducing a supersandwich reaction to increase the DNA length, the electrochemical signal was further amplified, leading to a detection limit of 0.52 × 10{sup −16} g mL{sup −1}. And it rendered satisfactory analytical performance for the determination of CEA in serum samples. Furthermore, it exhibited good reproducibility and stability; meanwhile, it also showed excellent specificity due to the specific recognition of antigen by antibody. Therefore, the DNA template synthesized Pd nanoparticles based signal amplification approach has great potential in clinical applications and is also suitable for quantification of biomarkers at ultralow level. - Graphical abstract: A novel label-free and enzyme-free electrochemical immunoassay based on proximity hybridization-regulated catalytic DNA hairpin assemblies for recycling of the CEA. - Highlights: • A novel enzyme-free electrochemical immunosensor was developed for detection of CEA. • The signal amplification was based on catalytic DNA hairpin assembly and DNA-template-synthesized Pd nanoparticles. • The biosensor could detect CEA down to 0.52 × 10{sup −16} g mL{sup −1} level with a dynamic range spanning 5 orders of magnitude.

Characterization of hematite nanoparticles synthesized via two different pathways

Science.gov (United States)

Das, Soumya; Hendry, M. Jim

2014-08-01

Hematite is one of the most common and thermodynamically stable iron oxides found in both natural and anthropogenic systems. Owing to its ubiquity, stability, moderate specific surface area, and ability to sequester metals and metalloids from aquatic systems, it has been the subject of a large number of adsorption studies published during the past few decades. Although preparation techniques are known to affect the surface morphology of hematite nanoparticles, the effects of aging under environmentally relevant conditions have yet to be tested with respect to surface morphology, surface area, and adsorptive capacity. We prepared hematite via two different pathways and aged it under highly alkaline conditions encountered in many mill tailings settings. Crystal habits and morphologies of the hematite nanoparticles were analyzed via scanning electron microscopy and transmission electron microscopy. X-ray diffraction, Raman spectroscopy, and Brunauer-Emmett-Teller surface area analyses were also conducted on the hematite nanoparticles before and after aging. The hematite synthesized via an Fe(III) salt solution (average particle size 37 nm) was morphologically and structurally different from the hematite synthesized via ferrihydrite aging (average particle size 144 nm). Overall, our data demonstrate that the crystallinity of hematite produced via ferrihydrite transformation is susceptible to morphological alterations/modifications. In contrast, the hematite formed via hydrolysis of an Fe(III) salt solution remains very stable in terms of structure, size, and morphology even under extreme experimental conditions.

The effect of poly vinyl alcohol (PVA) surfactant on phase formation and magnetic properties of hydrothermally synthesized CoFe{sub 2}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Jalalian, M.; Mirkazemi, S.M., E-mail: mirkazemi@iust.ac.ir; Alamolhoda, S.

2016-12-01

Nanoparticles of CoFe{sub 2}O{sub 4} were synthesized by hydrothermal process at 190 °C with and without poly vinyl alcohol (PVA) addition using treatment durations of 1.5–6 h. The synthesized powders were characterized with X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), Field emission scanning electron microscope (FESEM) and vibration sample magnetometer (VSM) techniques. XRD results show presence of CoFe{sub 2}O{sub 4} as the main phase and Co{sub 3}O{sub 4} as the lateral phase in some samples. The results show that in the samples synthesized without PVA addition considerable amount of lateral phase is present after 3 h of hydrothermal treatment while with PVA addition this phase is undetectable in the XRD patterns of the sample synthesized at the same conditions. Microstructural studies represent increasing of particle size with increasing of hydrothermal duration and formation of coarser particles with PVA addition. The highest maximum magnetization (M{sub max}) values in both of the samples that were synthesized with and without PVA addition are about 59 emu/g that were obtained after 4.5 h of hydrothermal treatment. Intrinsic coercive field ({sub i}H{sub c}) value of the sample without PVA addition increases from 210 to 430 Oe. While with PVA addition the {sub i}H{sub c} value changes from 83 Oe to 493 Oe. The mechanism of changes in M{sub max} and {sub i}H{sub c} values has been explained. - Highlights: • Nanoparticles of CoFe{sub 2}O{sub 4} hydrothermally synthesized with and without PVA addition. • PVA addition facilitates formation of single phase cobalt ferrite. • Coarser particles would be obtained with PVA addition. • The highest M{sub max} values in the samples with and without PVA are equal to 59 emu/g. • The highest {sub i}H{sub c} values are equalt to 320 and 493 Oe without and with PVA respectively.

A facile route to synthesize nanogels doped with silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Coll Ferrer, M. Carme [University of Pennsylvania, Department of Materials Science (United States); Ferrier, Robert C. [University of Pennsylvania, Department of Chemical and Biomolecular Engineering (United States); Eckmann, David M. [University of Pennsylvania, Department of Anesthesiology and Critical Care (United States); Composto, Russell J., E-mail: composto@seas.upenn.edu [University of Pennsylvania, Department of Materials Science (United States)

2013-01-15

In this study, we describe a simple method to prepare hybrid nanogels consisting of a biocompatible core-shell polymer host containing silver nanoparticles. First, the nanogels (NG, {approx}160 nm) containing a lysozyme rich core and a dextran rich shell, are prepared via Maillard and heat-gelation reactions. Second, silver nanoparticles (Ag NPs, {approx}5 nm) are synthesized 'in situ' in the NG solution without requiring additional reducing agents. This approach leads to stable Ag NPs located in the NG. Furthermore, we demonstrate that the amount of Ag NPs in the NG can be tuned by varying silver precursor concentration. Hybrid nanogels with silver nanoparticles have potential in antimicrobial, optical, and therapeutic applications.

A facile route to synthesize nanogels doped with silver nanoparticles

International Nuclear Information System (INIS)

Coll Ferrer, M. Carme; Ferrier, Robert C.; Eckmann, David M.; Composto, Russell J.

2013-01-01

In this study, we describe a simple method to prepare hybrid nanogels consisting of a biocompatible core–shell polymer host containing silver nanoparticles. First, the nanogels (NG, ∼160 nm) containing a lysozyme rich core and a dextran rich shell, are prepared via Maillard and heat-gelation reactions. Second, silver nanoparticles (Ag NPs, ∼5 nm) are synthesized “in situ” in the NG solution without requiring additional reducing agents. This approach leads to stable Ag NPs located in the NG. Furthermore, we demonstrate that the amount of Ag NPs in the NG can be tuned by varying silver precursor concentration. Hybrid nanogels with silver nanoparticles have potential in antimicrobial, optical, and therapeutic applications.

Measurement of discrete energy-level spectra in individual chemically synthesized gold nanoparticles

DEFF Research Database (Denmark)

Kuemmeth, Ferdinand; Bolotin, Kirill I; Shi, Su-Fei

2008-01-01

We form single-electron transistors from individual chemically synthesized gold nanoparticles, 5-15 nm in diameter, with monolayers of organic molecules serving as tunnel barriers. These devices allow us to measure the discrete electronic energy levels of individual gold nanoparticles that are......, by virtue of chemical synthesis, well-defined in their composition, size and shape. We show that the nanoparticles are nonmagnetic and have spectra in good accord with random-matrix-theory predictions taking into account strong spin-orbit coupling....

Effect of chemically and biologically synthesized Ag nanoparticles on the algae growth inhibition

Science.gov (United States)

Anna, Mražiková; Oksana, Velgosová; Jana, Kavuličová

2017-12-01

Over the past few years green methods for preparation of silver nanoparticles has become necessary due to its friendly influence on ecosystem. In the present work antimicrobial properties of biologically synthesized silver nanoparticles (Bio-AgNPs) using green algae extract and chemically synthesized silver nanoparticles (Chem-AgNPs) using sodium citrate against algae Parachlorella kessleri is investigated. Both used Bio-AgNPs and Chem-AgNPs exhibit long-term stability as demonstrated by UV-vis spectroscopy measurements. The results revealed stronger toxic effects of Bio-AgNPs on agar plates what was confirmed clear inhibition zone around wells impregnated with Bio-AgNPs. On the other hand Bio-AgNPs were confirmed to be less toxic in aquatic environments for the growths of green algae P. kessleri comparing to Chem-AgNPs.

Comparative study of synthesized silver and gold nanoparticles ...

Indian Academy of Sciences (India)

The present investigation aimed at comparing the synthesis, characterization and in vitro anticancer ... Bauhinia tomentosa Linn; silver nanoparticles; gold nanoparticles; A-549; HEp-2; MCF-7. 1. Introduction ..... Methods 65 55. [33] Singh A K ...

Antimicrobial potential of green synthesized CeO2 nanoparticles from Olea europaea leaf extract

Directory of Open Access Journals (Sweden)

Maqbool Q

2016-10-01

Full Text Available Qaisar Maqbool,1 Mudassar Nazar,1 Sania Naz,2 Talib Hussain,3 Nyla Jabeen,4 Rizwan Kausar,5 Sadaf Anwaar,4 Fazal Abbas,6,7 Tariq Jan6 1Department of Biotechnology, Virtual University of Pakistan, Lahore, Pakistan; 2Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan; 3National Institute of Vacuum Science and Technology (NINVAST, Islamabad, Pakistan; 4Department of Biotechnology and Bioinformatics Lab., International Islamic University, Islamabad, Pakistan; 5Department of Chemistry, University of Sargodha, Sargodha, Pakistan; 6Department of Physics, International Islamic University, Islamabad, Pakistan; 7Interdisciplinary Research Organization, University of Chakwal (UOC, Chakwal, Pakistan Abstract: This article reports the green fabrication of cerium oxide nanoparticles (CeO2 NPs using Olea europaea leaf extract and their applications as effective antimicrobial agents. O. europaea leaf extract functions as a chelating agent for reduction of cerium nitrate. The resulting CeO2 NPs exhibit pure single-face cubic structure, which is examined by X-ray diffraction, with a uniform spherical shape and a mean size 24 nm observed through scanning electron microscopy and transmission electron microscopy. Ultraviolet-visible spectroscopy confirms the characteristic absorption peak of CeO2 NPs at 315 nm. Fourier transform infrared spectroscopy reflects stretching frequencies at 459 cm-1, showing utilization of natural components for the production of NPs. Thermal gravimetric analysis predicts the successful capping of CeO2 NPs by bioactive molecules present in the plant extract. The antimicrobial studies show significant zone of inhibition against bacterial and fungal strains. The higher activities shown by the green synthesized NPs than the plant extract lead to the conclusion that they can be effectively used in biomedical application. Furthermore, reduction of cerium salt by plant extract will reduce environmental impact over

Evaluation of cytotoxicity of polypyrrole nanoparticles synthesized by oxidative polymerization

Energy Technology Data Exchange (ETDEWEB)

Vaitkuviene, Aida [Department of Physical Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Department of Stem Cell Biology, State Research Institute Center for Innovative Medicine, Zygimantu 9, LT-01102 Vilnius (Lithuania); Kaseta, Vytautas [Department of Stem Cell Biology, State Research Institute Center for Innovative Medicine, Zygimantu 9, LT-01102 Vilnius (Lithuania); Voronovic, Jaroslav [Department of Physical Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Ramanauskaite, Giedre; Biziuleviciene, Gene [Department of Stem Cell Biology, State Research Institute Center for Innovative Medicine, Zygimantu 9, LT-01102 Vilnius (Lithuania); Ramanaviciene, Almira [NanoTechnas–Center of Nanotechnology and Material Science at Department of Analytical and Environmental Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, 03225 Vilnius (Lithuania); Ramanavicius, Arunas, E-mail: Arunas.Ramanavicius@chf.vu.lt [Department of Physical Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Laboratory of BioNanoTechnology, Department of Materials Science and Electronics, Institute of Semiconductor Physics, State Scientific Research Institute Centre for Physical Sciences and Technology, A. Gostauto 11, LT-01108 Vilnius (Lithuania)

2013-04-15

Highlights: ► Polypyrrole nanoparticles synthesized by environmentally friendly polymerization at high concentrations are cytotoxic. ► Primary mouse embryonic fibroblast, mouse hepatoma and human T lymphocyte Jurkat cell lines were treated by Ppy nanoparticles. ► Polypyrrole nanoparticles at high concentrations inhibit cell proliferation. -- Abstract: Polypyrrole (Ppy) is known as biocompatible material, which is used in some diverse biomedical applications and seeming to be a very promising for advanced biotechnological applications. In order to increase our understanding about biocompatibility of Ppy, in this study pure Ppy nanoparticles (Ppy-NPs) of fixed size and morphology were prepared by one-step oxidative polymerization and their cyto-compatibility was evaluated. The impact of different concentration of Ppy nanoparticles on primary mouse embryonic fibroblasts (MEF), mouse hepatoma cell line (MH-22A), and human T lymphocyte Jurkat cell line was investigated. Cell morphology, viability/proliferation after the treatment by Ppy nanoparticles was evaluated. Obtained results showed that Ppy nanoparticles at low concentrations are biocompatible, while at high concentrations they became cytotoxic for Jurkat, MEF and MH-22A cells, and it was found that cytotoxic effect is dose-dependent.

ZnO doped SnO2 nanoparticles heterojunction photo-catalyst for environmental remediation

International Nuclear Information System (INIS)

Lamba, Randeep; Umar, Ahmad; Mehta, S.K.; Kansal, Sushil Kumar

2015-01-01

ZnO doped SnO 2 nanoparticles were synthesized by facile and simple hydrothermal technique and used as an effective photocatalyst for the photocatalytic degradation of harmful and toxic organic dye. The prepared nanoparticles were characterized in detail using different techniques for morphological, structural and optical properties. The characterization results revealed that the synthesized nanoparticles possess both crystal phases of tetragonal rutile phase of pure SnO 2 and wurtzite hexagonal phase of ZnO. In addition, the nanoparticles were synthesized in very high quantity with good crystallinity. The photocatalytic activity of prepared nanoparticles was evaluated by the photocatalytic degradation of methylene blue (MB) dye. Detailed photocatalytic experiments based on the effects of irradiation time, catalyst dose and pH were performed and presented in this paper. The detailed photocatalytic experiments revealed that the synthesized ZnO doped SnO 2 nanoparticles heterojunction photocatalyst exhibit best photocatalytic performance when the catalyst dose was 0.25 g/L and pH = 10. ZnO doped SnO 2 nanoparticles heterojunction photocatalyst was also compared with commercially available TiO 2 (PC-50), TiO 2 (PC-500) and SnO 2 and interestingly ZnO doped SnO 2 nanoparticles exhibited superior photocatalytic performance. The presented work demonstrates that the prepared ZnO doped SnO 2 nanoparticles are promising material for the photocatalytic degradation of organic dyes and toxic chemicals. - Highlights: • Synthesis of well-crystalline ZnO-doped SnO 2 nanoparticles. • Excellent morphological, crystalline and photoluminescent properties. • Efficient environmental remediation using ZnO-doped SnO 2 nanoparticles.

Kinetics of oxygen adsorption on ZnS nanoparticles synthesized by precipitation process

Directory of Open Access Journals (Sweden)

Ahmadi Reza

2016-06-01

Full Text Available ZnS nanoparticles were synthesized through a one-step precipitation process. Effect of time and temperature on the formation reaction was investigated. The synthesized samples were characterized by X-ray diffraction (XRD, ultraviolet (UV visible absorption and photoluminescence (PL spectrophotometry. Based on XRD and UV-Vis data, the particles produced at 70 °C had a mean particle size of about 5 nm. Increasing time and temperature of the synthesis reaction resulted in photoluminescence intensification. PL spectroscopy helped understanding the adsorption kinetics of oxygen on ZnS nanoparticles during the precipitation synthesis process. Fabrication of ZnS structures with appropriate oxygen adsorption capacity was suggested as a means of PL emission intensity control.

Synthesis and Physicochemical Characterization of Mesoporous SiO2 Nanoparticles

Directory of Open Access Journals (Sweden)

Dharani Das

2014-01-01

Full Text Available There exists a knowledge gap in understanding potential toxicity of mesoporous silica nanoparticles. A critical step in assessing toxicity of these particles is to have a wide size range with different chemistries and physicochemical properties. There are several challenges when synthesizing mesoporous silica nanoparticles over a wide range of sizes including (1 nonuniform synthesis protocols using the same starting materials, (2 the low material yield in a single batch synthesis (especially for particles below 60–70 nm, and (3 morphological instability during surfactant removal process and surface modifications. In this study, we synthesized a library of mesoporous silica nanoparticles with approximate particle sizes of 25, 70, 100, 170, and 600 nm. Surfaces of the silica nanoparticles were modified with hydrophilic-CH2–(CH22–COOH and relatively hydrophobic-CH2–(CH210–COOH functional groups. All silica nanoparticles were analysed for morphology, surface functionality, surface area/pore volume, surface organic content, and dispersion characteristics in liquid media. Our analysis revealed the synthesis of a spectrum of monodisperse bare and surface modified mesoporous silica nanoparticles with a narrow particle size distribution and devoid of cocontaminants critical for toxicity studies. Complete physicochemical characterization of these synthetic mesoporous silica nanoparticles will permit systematic toxicology studies for investigation of structure-activity relationships.

Biogenic silver nanoparticles synthesized with rhamnogalacturonan gum: Antibacterial activity, cytotoxicity and its mode of action

Directory of Open Access Journals (Sweden)

Aruna Jyothi Kora

2018-03-01

Full Text Available Silver nanoparticles synthesized from gum kondagogu (5 nm were used to evaluate the antibacterial activity against Gram-positive and Gram-negative bacteria. To decipher the mode of antibacterial action of nanoparticles, a comprehensive study was carried out employing a variety of susceptibility assays: micro-broth dilution, antibiofilm activity, growth kinetics, cytoplasmic content leakage, membrane permeabilization, etc. The production of reactive oxygen species (ROS and cell surface damage during bacterial nanoparticle interaction were also demonstrated using dichlorodihydrofluorescein diacetate, N-acetylcysteine; and scanning electron microscopy and energy dispersive X-ray spectra. Further, the biocompatibility with HeLa cell line was also evaluated. Compared to earlier reports, the minimum inhibitory concentration values were lower by 3.2- and 16-folds for Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli strains, respectively. The minimum bactericidal concentration values were lower by 4 and 50-folds. Thus, the biogenic silver nanoparticles were found to be more potent bactericidal agents in terms of concentration. The nanoparticles exhibited significant antibiofilm activity against test strains at 2 μg mL−1, which can have implications in the treatment of drug resistant bacterial infections caused by biofilms. Growth curve in nanoparticle supplemented indicated a faster inhibition in Gram-negative bacteria as compared to Gram-positive. Treatment with nanoparticles caused cytoplasmic content leakage and membrane permeabilization in a dose dependent manner, an evidence for membrane damage. The observations noted in our study substantiated the association of ROS and membrane damage in the antibacterial action of silver nanoparticles. The promising antibacterial activity enables these nanoparticles as potential bactericidal material for various environmental and biomedical applications.

Quorum quenching and antibacterial activity of silver nanoparticles synthesized from Sargassum polyphyllum

Directory of Open Access Journals (Sweden)

Mani Arunkumar

2014-03-01

Full Text Available Development of efficient methodology for the green synthesis of silver nanoparticles using marine algae is a modern area of research in the field of phyconanotechnology. In this regard, the present study deals with green synthesis of silver nanoparticles (AgNPs by using aqueous extracts of marine brown seaweed Sargassum polyphyllum. UV-visible spectral analysis reveals the formation of AgNPs by showing absorption maximum at 420 nm wavelength and SEM analysis clearly elucidate the polydispersed structure of AgNPs without aggregation and ranged in size from 37-43 nm. X-ray Diffraction pattern confirmed the AgNPs crystalline personality. The synthesized AgNPs showed more enduring antibacterial activity against test bacterial pathogens. Furthermore, the synthesized AgNPs exhibited varying level of inhibition of violacein production and swarming motility. In the near future, silver nanoparticles can be extremely useful in clinical medicine as an alternative method for the treatment of wound infection.

Antibacterial effect of novel synthesized sulfated β-cyclodextrin crosslinked cotton fabric and its improved antibacterial activities with ZnO, TiO2 and Ag nanoparticles coating.

Science.gov (United States)

Selvam, S; Rajiv Gandhi, R; Suresh, J; Gowri, S; Ravikumar, S; Sundrarajan, M

2012-09-15

Sulfated β-cyclodextrin was synthesized from sulfonation of β-cyclodextrin and sulfated polymer was crosslinked with cotton fabric using ethylenediaminetetraacetic acid as crosslinker. ZnO, TiO(2) and Ag nanoparticles were prepared and characterized by XRD, UV, DLS, SEM and PSA. The prepared nanoparticles were coated on crosslinked cotton fabric. The crosslinking and nanoparticles coating effects of cotton fabrics were studied by FTIR and SEM analysis. The antibacterial test was done against gram positive Staphylococcus aureus and gram negative Escherichia coli bacterium. Copyright © 2012 Elsevier B.V. All rights reserved.

Size-tunable silver nanoparticles synthesized by using aminopolycarboxylic acids at ambient-temperature

International Nuclear Information System (INIS)

Malkar, Vishwabharati V.; Chadha, R.; Biswas, N.; Mukherjee, T.; Kapoor, S.

2009-01-01

Full text: Stable aqueous sols of silver nanoparticles are prepared by using various aminopolycarboxylic acids as stabilizing agents at ambient temperature. The precursor silver perchlorate is reduced using γ radiations. Interestingly, it was observed that size of silver nanoparticles obtained could be tuned using various aminopolycarboxylic acids of varying carboxylic acid groups The silver sols synthesized by this method were stable for months and particles obtained were monodisperse in almost all cases. Particle formation was observed at equimolar concentration of silver and aminopolycarboxylic acids. The stabilization of particles even in the absence of any polymer indicates that the adsorption of aminopolycarboxylic acids on silver particle is a spontaneous process. The adsorbed aminopolycarboxylic acids can saturate the residual valence force of the silver atom on the particle surface by coordinating with unoccupied orbital. Adsorption of aminopolycarboxylic acids does not lead to any change in surface plasmon band of silver nanoparticles; this indicates that anions in the double layer on the colloidal particle have different chemical properties from the free anions. Synthesized silver nanoparticles were characterized by UV-visible spectrophotometer, X-ray Diffraction, Dynamic Light Scattering and Transmission Electron Microscope

The impacts of growth temperature on morphologies, compositions and optical properties of Mg-doped ZnO nanomaterials by chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Wang, X.H., E-mail: wangxh@sdju.edu.cn [School of Mechanical Engineering, Shanghai Dianji University, 1201 Jiang Chuan Road, Shanghai 200245 (China); Huang, L.Q.; Niu, L.J.; Li, R.B. [School of Mechanical Engineering, Shanghai Dianji University, 1201 Jiang Chuan Road, Shanghai 200245 (China); Fan, D.H. [Institute of Functional Materials Research, Department of Mathematics and Physics, Wuyi University, Jiangmen 529020 (China); Zhang, F.B.; Chen, Z.W.; Wang, X.; Guo, Q.X. [Department of Electrical and Electronic Engineering, Synchrotron Light Application Center, Saga University, Saga 840-8502 (Japan)

2015-02-15

Highlights: • Mg-doped ZnO nanomaterials were fabricated by chemical vapor deposition (CVD). • Growth temperature determines the characteristics of Zn{sub 1-x}Mg{sub x}O nanomaterials. • The modulation of band gap is caused by Mg addition. - Abstract: The Mg-doped ZnO (Zn{sub 1-x}Mg{sub x}O) nanomaterials with different morphologies of nanoparticles, partially opened nanowire-on-spherical shells, hemispheric shells and chain-like nanoparticles were synthesized at 750, 850, 900 and 1000 °C by a simple chemical vapor deposition. The energy dispersive X-ray (EDX) measurements indicate that Mg content increases from 2.87 at.% to 5.01 at.% with the increase of growth temperature from 750 to 1000 °C. The measurement results of X-ray diffraction (XRD) show that the (0 0 2) peaks of Zn{sub 1-x}Mg{sub x}O nanomaterials shift to higher diffraction angle with the increase of Mg content, implying that Mg{sup 2+} is substituted into Zn{sup 2+} site. The absorption spectra at room temperature exhibit that the band gap of the Mg-doped ZnO nanomaterials increases with the Mg concentration, illustrating that the modulation of band gap is caused by Mg addition. The PL measurements show that UV peak from Zn{sub 1-x}Mg{sub x}O nanomaterials is shifted towards lower wavelength side (blue shift) from 381 nm to 372 nm with the increase of the Mg dopant content. The room-temperature Raman spectra show that the crystal quality of the Zn{sub 1-x}Mg{sub x}O nanomaterials is improved with the increase of growth temperature, and the Mg dopants do not decrease the crystal quality of ZnO nanomaterials.

Crystal structure of superparamagnetic Mg{sub 0.2}Ca{sub 0.8}Fe{sub 2}O{sub 4} nanoparticles synthesized by sol–gel method

Energy Technology Data Exchange (ETDEWEB)

Escamilla-Pérez, A.M., E-mail: angel.mep@gmail.com [Cinvestav-Unidad Saltillo, Industria Metalúrgica No. 1062, Parque Industrial Saltillo-Ramos Arizpe, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Cortés-Hernández, D.A., E-mail: dora.cortes@cinvestav.edu.mx [Cinvestav-Unidad Saltillo, Industria Metalúrgica No. 1062, Parque Industrial Saltillo-Ramos Arizpe, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Almanza-Robles, J.M. [Cinvestav-Unidad Saltillo, Industria Metalúrgica No. 1062, Parque Industrial Saltillo-Ramos Arizpe, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Mantovani, D.; Chevallier, P. [Laboratory for Biomaterials and Bioengineering, Department of Materials Engineering and University Hospital Research Center, Laval University, Quebec City, QC (Canada)

2015-01-15

Powders of magnetic iron oxide nanoparticles (Mg{sub 0.2}Ca{sub 0.8}Fe{sub 2}O{sub 4}) were prepared by a sol–gel method using ethylene glycol and nitrates of Fe, Ca and Mg as starting materials. Those powders were heat treated at different temperatures (573, 673, 773 and 873 K). In order to evaluate the effect of the heat treatment temperature on the nanoferrites properties, X-ray diffraction (XRD), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques were used. It was found that the reaction products exhibit nanometric sizes and superparamagnetic behavior. It is also demonstrated that, as the heat treatment temperature increases, the particle size and the saturation magnetization of the nanoferrites are increased. - Highlights: • Mg{sub 0.2}Ca{sub 0.8}Fe{sub 2}O{sub 4} superparamagnetic nanoparticles were successfully synthesized. • Particle average sizes of Ca–Mg ferrites were within the range of 8–25 nm. • The nanoferrite treated at 873 K showed a stoichiometry close to Mg{sub 0.2}Ca{sub 0.8}Fe{sub 2}O{sub 4}. • The heat treatment temperature has a strong effect on the crystal structure. • These nanoparticles are potential materials for magnetic hyperthermia.

Antibacterial effect of silk treated with silver and copper nanoparticles synthesized by pulsed laser ablation in distilled water

Science.gov (United States)

Baruah, Prahlad K.; Raman, Moghe A.; Chakrabartty, Ishani; Rangan, Latha; Sharma, Ashwini K.; Khare, Alika

2018-05-01

The antibacterial activity of three kinds of silks viz. Eri, Pat and Muga treated with silver and copper nanoparticles is reported in this paper. The nanoparticles have been synthesized by pulsed laser ablation of the respective metal targets in distilled water. Treatment of the silk pellets with the synthesized nanoparticles exhibited definite antibacterial activity whereas no such activity is observed in the untreated silk pellets.

Observations and modeling of the transiting exoplanets XO-2b, HAT-P-18b, and WASP-80b

Directory of Open Access Journals (Sweden)

Kjurkchieva Diana P.

2017-01-01

Full Text Available We present photometric observations and transit solutions of the exoplanets XO-2b, HAT-P-18b and WASP 80b. Our solution of the XO-2b transit gave system parameters whose values are close to those of the previous studies. The solutions of the new transits of HAT-P-18b and WASP 80b differ from the previous ones by bigger stellar and planet radii. We obtained new values of the target initial epochs corresponding to slightly different periods. Our investigation reaffirmed that small telescopes can be used successfully for the study of exoplanets orbiting stars brighter than 13 mag.

Synthesis and characterization of Co and Mn doped NiO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Vallalperuman, Kaliyan; Parthibavarman, Mathivanan; Sathishkumar, Sekar; Durairaj, Manickam [Mahendra Engineering College, Tiruchengode (India); Thavamani, Kuppusamy [AVS Technical Campus,, Salem (India)

2014-04-15

Diluted magnetic semiconductors (DMS) are intensively studied for their potential spintronics applications, especially those with Curie temperature above the room temperature. Ni{sub 1-x}Mn{sub x}O and Ni{sub 1-x}Co{sub x}O (x=1% and 2%), nanoparticles with size around 40-50 nm, were prepared by co-precipitation method. An NiO single phase structure was confirmed by powder X-ray diffraction measurements. Also, diffraction peaks show a systematic shift towards higher angle with an increase in Mn concentration, which is associated with the lattice variation. The samples were pelleted and examined for its magnetic property using a vibrating sample magnetometer (VSM); it indicates paramagnetic-like behavior at room temperature. The increase in a.c conductivity with increasing temperature is attributed to the increase in drift mobility of the charge carriers.

Asymmetric dumbbell-shaped silver nanoparticles and spherical gold nanoparticles green-synthesized by mangosteen (Garcinia mangostana pericarp waste extracts

Directory of Open Access Journals (Sweden)

Park JS

2017-09-01

Full Text Available Ji Su Park, Eun-Young Ahn, Youmie Park College of Pharmacy, Inje Institute of Pharmaceutical Sciences and Research, Inje University, Gimhae, Gyeongnam, Republic of Korea Abstract: Mangosteen (Garcinia mangostana pericarp waste extract was used to synthesize gold and silver nanoparticles by a green strategy. The extract was both a reducing and stabilizing agent during synthesis. Phytochemical screening of the extract was conducted to obtain information regarding the presence/absence of primary and secondary metabolites in the extract. The in vitro antioxidant activity results demonstrated that the extract had excellent antioxidant activity, which was comparable to a standard (butylated hydroxy toluene. Spherical gold nanoparticles (gold nanoparticles green synthesized by mangosteen pericarp extract [GM-AuNPs] with an average size of 15.37±3.99 to 44.20±16.99 nm were observed in high-resolution transmission electron microscopy (HR-TEM images. Most interestingly, the silver nanoparticles (silver nanoparticles green synthesized by mangosteen pericarp extract [GM-AgNPs] had asymmetric nanodumbbell shapes where one tail grew from a spherical head. The average head size was measured to be 13.65±5.07 to 31.08±3.99 nm from HR-TEM images. The hydrodynamic size of both nanoparticles tended to increase with increasing extract concentration. Large negative zeta potentials (–18.92 to –34.77 mV suggested that each nanoparticle solution possessed excellent colloidal stability. The reaction yields were 99.7% for GM-AuNPs and 82.8% for GM-AgNPs, which were assessed by inductively coupled plasma optical emission spectroscopy. A high-resolution X-ray diffraction pattern confirmed the face-centered cubic structure of both nanoparticles. Based on phytochemical screening and Fourier transform infrared spectra, the hydroxyl functional groups of carbohydrates, flavonoids, glycosides, and phenolic compounds were most likely involved in a reduction reaction of

Green synthesized zinc oxide nanoparticles as a therapeutic tool to combat candidiasis

Science.gov (United States)

Rathod, Tejas; Padalia, Hemali; Chanda, Sumitra

2017-05-01

Advancement of modern medicine, the increasing ratio of immunocompromised and immunosuppressive individuals is increased in hospitalized with serious underlying disease. This has resulted in a rise in the incidence of fungal infections, especially those due to Candida species. For many years the conventional antibiotic therapy has been critical in the fight against Candidiasis. Candidiasis is a fungal infection due to various types of Candida (yeast) species. In this study, zinc oxide nanoparticles (ZnONPs) were synthesized using the Cinnamomum verum bark plus Cassia auriculata leaf powder extracts. The characterization of synthesized ZnONPs was done by UV-Vis spectrophotometer and SEM analysis. The average size of nanoparticles was 77 nm. Synergistic anticandidal activity of ZnONPs (ZnONPs plus antibiotics) was determined by disc diffusion method against 16 multidrug resistant clinical pathogens of Candida species. Antibiotic Ketoconazole plus ZnONPs showed best synergistic anticandidal activity against all the 16 isolates. Green synthesized ZnONPs appears to be a new promising approach to fight against Candidiasis.

Biological application of green silver nanoparticle synthesized from leaf extract of Rauvolfi serpentina Benth

Directory of Open Access Journals (Sweden)

Sudipta Panja

2016-07-01

Full Text Available Objective: To synthesize silver nanoparticles (AgNPs from the leaf extract of Rauvolfia serpentina Benth and examination of their various biological activities. Methods: An ecofriendly, easy, one step, non-toxic and inexpensive approach is used, where aqueous plant extract acts as a reducing as well as stabilizing agent of AgNPs. The nanoparticles were characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy analysis. Results: Surface plasmon resonance of the nanoparticles was observed at 427 nm in UV-vis spectroscopy. Fourier transform infrared spectroscopy result confirms that the plant extract acts as the reducing as well as the capping agent of the AgNPs. Transmission electron microscopy indicated that the synthesized nanoparticles are spherical in shape and approximately 7–10 nm in size, whereas the crystalline nature with face-centered cubic structure of the AgNPs was detected by X-ray diffraction analysis. Presence of silver in the AgNPs is 31.43% by weight, as confirmed by energy-dispersive X-ray spectroscopy. The synthesized AgNPs have antimicrobial activities against human pathogenic microorganisms. It also shows larvicidal activity and cytotoxicity against HeLa, MCF-7 cell lines. Conclusions: Synthesized spherical shaped AgNPs from the leaf extract of Rauvolfia serpentina Benth have antimicrobial and larvicidal activities as well as cytotoxicity against HeLa and MCF-7 cell lines.

The effect of biologically and chemically synthesized silver nanoparticles (AgNPs) on biofilm formation

Science.gov (United States)

Chojniak, Joanna; Biedroń, Izabela; Mendrek, Barbara; Płaza, Grażyna

2017-11-01

Bionanotechnology has emerged up as integration between biotechnology and nanotechnology for developing biosynthetic and environmental-friendly technology for synthesis of nanomaterials. Different types of nanomaterials like copper, zinc, titanium, magnesium, gold, and silver have applied in the various industries but silver nanoparticles have proved to be most effective against bacteria, viruses and eukaryotic microorganisms. The antimicrobial property of silver nanoparticles are widely known. Due to strong antibacterial property silver nanoparticles are used, e.g. in clothing, food industry, sunscreens, cosmetics and many household and environmental appliances. The aim of the study was to compare the effect of silver nanoparticles (AgNPs) synthesized biologically and chemically on the biofilm formation. The biofilm was formed by the bacteria isolated from the water supply network. The commonly used crystal violet assay (CV) was applied for biofilm analysis. In this study effect of biologically synthesized Ag-NPs on the biofilm formation was evaluated.

Mechanical responses of Zn{sub 1-x}Mn{sub x}O epitaxial thin films

Energy Technology Data Exchange (ETDEWEB)

Chang, Teng-Ruey [Department of Industrial Engineering and Management, Nan Kai University of Techonology, Nantou 54243, Taiwan (China); Tsai, Chien-Huang, E-mail: chtsai12@gmail.com [Department of Automation Engineering, Nan Kai University of Techonology, Nantou 54243, Taiwan (China)

2011-10-15

In this study, we used nanoindentation to investigate the effect of the doping of Mn into ZnO buffer layers on the epitaxial growth of ZnO through plasma-assisted molecular beam epitaxy on c-plane sapphire substrates. We characterized the variation of the mechanical properties of Zn{sub 1-x}Mn{sub x}O alloys as a function of the Mn content in the range (x) from 0 to 0.16, as well as analyzing their microstructures using high-resolution transmission electron microscopy. The presence of the Mn-doped ZnO buffer layer enhanced the nanomechanical properties of the ZnO epilayers significantly. From their Berkovich indenter responses, plots of the Young's modulus (E) and hardness (H) of these films revealed that the value of E increased relatively steadily upon increasing the Mn composition, whereas the value of H reached its maximum when x was equal to 0.16. This discrepancy suggests that Zn{sub 1-x}Mn{sub x}O epilayers of higher Mn contents had higher shear resistances.

Study of interaction between tin dioxide nanoparticle and 1,4-dihydroxy 2,3-dimethyl 9,10-anthraquinone sensitizer

International Nuclear Information System (INIS)

Suvetha Rani, J.; Sasirekha, V.; Ramakrishnan, V.

2013-01-01

The interaction between 1,4-dihydroxy 2,3-dimethyl 9,10-anthraquinone (DHDMAQ) and tin dioxide nanoparticle (SnO 2 NPs) has been investigated using optical absorption and emission techniques. Tin dioxide nanoparticles have been synthesized by chemical precipitation method. The experimental results reveal that the fluorescence intensity of 1,4-dihydroxy 2,3-dimethyl 9,10-anthraquinone has been quenched as the concentration of the SnO 2 NPs increased. The Stern–Volmer plot indicates that SnO 2 NPs have dynamic quenching efficiency on the fluorescence nature of DHDMAQ. The obtained value of the association constant infers that there is an association between DHDMAQ and the SnO 2 nanoparticles. -- Highlights: • The interaction between DHDMAQ and SnO 2 NPs has been investigated using optical absorption and emission techniques. • The fluorescence intensity of the fluorophore has been quenched as the concentration of the SnO 2 NPs increased. • The Stern–Volmer plot indicates that SnO 2 NPs have dynamic quenching efficiency on the fluorescence nature of DHDMAQ

Synthesize of zinc nanoparticles using Indonesian velvet bean (Mucuna pruriens) extract and evaluate its potency in lowering catalepsy in mice

Science.gov (United States)

Eko Sardjono, Ratnaningsih; Khoerunnisa, Fitri; Musthopa, Iqbal; Khairunisa, Dinar; Astuti Suganda, Putri; Rachmawati, Rahmi

2018-01-01

This study aims to synthesize zinc nanoparticles using Indonesian velvet bean (Mucuna pruriens) seed extract and evaluate its potency in lowering catalepsy in mice. The research conducted consist of extraction of M. pruriens seed powder, synthesis of zinc-M. pruriens seed extract nanoparticles (Zn-MPn), characterization of Zn-MPn, and catalepsy test of Zn-MPn. M. pruriens seed powder was extracted by maceration using ethanol-water (1:1) at pH 3 adjusted with citric acid. The Zn-MPn was synthesized by reacting zinc acetate dihydrate (Zn(CH3COO2)2.2H2O) solution with M. pruriens seed extract for 40 min, dispersibility of the reaction was controlled by using sonication and ultrasonic homogenizer. The Zn-MPn obtained was characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM), and Fourier-transform infrared (FTIR). Catalepsy test of Zn-MPn was conducted at doses of 5, 10, 15, 20 and 25 mg/kg body weight. The results of SEM-EDX and TEM analysis showed that the Zn-MPn formed nanoparticles with a particle diameter of 55 nm. Based on FTIR analysis, the absorption band at 464.8 cm-1 was a typical absorption indicated the Zn-O interaction on Zn-MPn. Catalepsy test showed that Zn-MPn on the all five doses were able to lower the catalepsy in mice with the best dose was 10 mg/kg body weight.

Synthesis and photocatalytic studies of ZnS nanoparticles from heteroleptic complex of Zn(II) 1-cyano-1-carboethoxy-2,-2-ethylenedithiolato diisopropylthiourea and its adducts with N-donor ligands

Science.gov (United States)

Osuntokun, Jejenija; Ajibade, Peter A.; Onwudiwe, Damian C.

2016-12-01

Zinc complexes of the type [Zn(diptu)2(ced)] (1), [Zn(diptu)2(ced)py] (2), [Zn(diptu)2(ced)bpy] (3), and [Zn(diptu)2(ced)phen] (4), (where (diptu)2(ced) = 1-cyano-1-carboethoxyethylene-2,2-dithiolato-κS,S‧-bis(N,N-diisopropyllthiourea), py = pyridine, bpy = 2, 2‧ bipyridine and phen = 1, 10 phenanthroline have been synthesized and characterized by elemental analyses, Fourier transform infra-red (FTIR) and Nuclear magnetic resonance (NMR) spectroscopies. The parent complex (1) was formulated as four coordinate species, which gave rise to 5 coordinate complex in (2) and six coordinate compounds in (3) and (4), with the dithiolate acting as bidentate chelating ligand. The complexes were used as single-source precursors for the synthesis of HDA-capped ZnS nanoparticles. The nanoparticles gave different morphologies with sizes in the range of 1.92-4.72 nm as observed from the TEM analysis and supported by XRD. The UV-vis spectroscopy showed that all the ZnS nanoparticles are blue shifted, with respect to the bulk, which confirmed quantum confinement. The photoluminescence spectra showed narrow and broad emission peaks around 290 and 360 nm which are ascribed to spontaneous emission peaks from band to band transition and surface states respectively. Photocatalytic activities of all the nanoparticles were investigated with methylene blue (MB) acting as the organic dye, and the UV-vis spectral revealed a gradual decrease in absorption peak that confirmed the degradation of the MB.

Spectroscopy investigation on chemo-catalytic, free radical scavenging and bactericidal properties of biogenic silver nanoparticles synthesized using Salicornia brachiata aqueous extract

Science.gov (United States)

Seralathan, Janani; Stevenson, Priscilla; Subramaniam, Shankar; Raghavan, Rachana; Pemaiah, Brindha; Sivasubramanian, Aravind; Veerappan, Anbazhagan

2014-01-01

Nanosized silver have been widely used in many applications, such as catalysis, photonics, sensors, medicine etc. Thus, there is an increasing need to develop high-yield, low cost, non-toxic and eco-friendly procedures for the synthesis of nanoparticles. Herein, we report an efficient, green synthesis of silver nanoparticles utilizing the aqueous extract of Salicornia brachiata, a tropical plant of the Chenopodiaceae family. Silver nanoparticles have been characterized by ultraviolet-visible spectroscopy, scanning electron microscopy and transmission electron microscopy. The morphology of the particles formed consists of highly diversified shapes like spherical, rod-like, prism, triangular, pentagonal and hexagonal pattern. However, addition of sodium hydroxide to the extract produces mostly spherical particles. The stable nanoparticles obtained using this green method show remarkable catalytic activity in the reduction of 4-nitro phenol to 4-amino phenol. The reduction catalyzed by silver nanoparticles followed the first-order kinetics, with a rate constant of, 0.6 × 10-2 s-1. The bactericidal activity of the synthesized silver nanoparticles against the pathogenic bacteria, Staphylococcus aureus, Staphylococcus aureus E, Bacillus subtilis and Escherichia coli, was also explored using REMA. The obtained results showed that the minimum inhibitory concentration required to induce bactericidal effect is lower than the control antibiotic, ciprofloxacin. In addition to these, the biogenic synthesized nanoparticles also exhibited excellent free radical scavenging activity.

Antibacterial Activity of Polyaniline Coated Silver Nanoparticles Synthesized from Piper Betle Leaves Extract.

Science.gov (United States)

Mamun Or Rashida, Md; Shafiul Islam, Md; Azizul Haque, Md; Arifur Rahman, Md; Tanvir Hossain, Md; Abdul Hamid, Md

2016-01-01

Plants or natural resources have been found to be a good alternative method for nanoparticles synthesis. In this study, polyaniline coated silver nanoparticles (AgNPs) synthesized from Piper betle leaves extract were investigated for their antibacterial activity. Silver nanoparticles were prepared from the reduction of silver nitrate and NaBH4 was used as reducing agent. Silver nanoparticles and extracts were mixed thoroughly and then coated by polyaniline. Prepared nanoparticles were characterized by Visual inspection, Ultraviolet-visible spectroscopy (UV), Fourier transform infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM) techniques. Antibacterial activities of the synthesized silver nanoparticles were tested against Staphylococcus aureus ATCC 25923, Salmonella typhi ATCC 14028, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. UV-Vis spectrum of reaction mixture showed strong absorption peak with centering at 400 nm. The FT-IR results imply that Ag-NPs were successfully synthesized and capped with bio-compounds present in P. betle. TEM image showed that Ag-NPs formed were well dispersed with a spherical structures and particle size ranging from 10 to 30 nm. The result revealed that Ag-Extract NPs showed 32.78±0.64 mm zone of inhibition against S. aureus, whereas norfloxacin (positive control) showed maximum 32.15±0.40 mm zone of inhibition for S. aureus. Again, maximum zone of inhibition 29.55±0.45 mm was found for S. typhi, 27.12±0.38 mm for E. coli and 21.95±0.45 mm for P. aeruginosa. The results obtained by this study can't be directly extrapolated to human; so further studies should be undertaken to established the strong antimicrobial activity of Ag-Extract NPs for drug development program.

Effects of citric acid additive on photoluminescence properties of YAG:Ce3+ nanoparticles synthesized by glycothermal reaction

International Nuclear Information System (INIS)

Asakura, R.; Isobe, T.; Kurokawa, K.; Takagi, T.; Aizawa, H.; Ohkubo, M.

2007-01-01

We synthesize Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ) nanoparticles in the presence of citric acid by glycothermal method. Fourier transform infrared absorption spectroscopy measurement indicates that the intensity of the peak corresponding to carboxyl groups coordinating to the nanoparticles increases with increasing amount of citric acid. At the same time, the primary particle diameter decreases from 10.2 to 4.0 nm. In addition, the internal quantum efficiency of the photoluminescence (PL) due to the 4f-5d transition of Ce 3+ increases from 22.0% to 40.1% with increasing amount of citric acid. Two kinds of PL decay lifetimes, 16-26 and 72-112 ns, are detected for YAG:Ce 3+ nanoparticles, whereas the micron sized YAG:Ce 3+ bulk shows the lifetime of 57 ns. We discuss these phenomena from the aspects of the coordination of citric acid and the incorporation of Ce 3+ ions into the nanoparticles

Green synthesis and antimicrobial activity of monodisperse silver nanoparticles synthesized using Ginkgo Biloba leaf extract

Energy Technology Data Exchange (ETDEWEB)

Ren, Yan-yu [School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi' an 710021 (China); Yang, Hui, E-mail: 549456369@qq.com [School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi' an 710021 (China); Wang, Tao [School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi' an 710021 (China); Wang, Chuang [Department of Highway & Bridge, Shaanxi Railway Institute, Weinan 714000 (China)

2016-11-25

Various parts of plants can be used as a raw material for the synthesis of nanoparticles, which is eco-friendly way and does not involve any harmful chemicals. In this project, Ginkgo biloba leaf, an abundantly available medicinal plant in China, was for the first time adopted as a reducing and stabilizing agent to synthesize smaller sized and stable silver nanoparticles (AgNPs). To improve the quality of AgNPs, the reduction was accelerated by changing the concentrations of initial Ag{sup +} (0.02, 0.04, 0.06 and 0.08 mol/L) of the reaction mixture consisting of silver nitrate solution (AgNO{sub 3}) and Ginkgo biloba leaf extract. At pH = 8 and lower AgNO{sub 3} concentration (0.02 mol/L), a colloid consisting of well-dispersed spherical nanoparticles was obtained. The synthesized nanocrystals were successfully characterized by UV–vis and XRD. TEM images revealed the size of the spherical AgNPs ranged between 10–16 nm. FTIR analysis revealed that biological macromolecules with groups of −NH{sub 2}, −OH, and others were distributed on the surface of the nanoparticles. The biosynthesized AgNPs exhibited good antibacterial activities against gram-negative bacteria and gram-positive bacteria. Compared to traditional chemical methods, Ginkgo biloba leaf extract provides an easy green synthetical way. It is anticipated that the biosynthesized AgNPs can be used in areas such as cosmetics, foods and medical applications. - Highlights: • Monodisperse silver nanoparticles were first prepared by a green synthetical way through Ginkgo Biloba leaf extract. • The synthesized AgNPs is of high crystallinity, stable and good dispersion with smaller sizes between 10–16 nm. • The achieved AgNPs exhibits good antibacterial activities. • The biosynthesis method is advantageous for its cost effectiveness, availability, portability, nontoxic and environmentally benign.

Green synthesis and antimicrobial activity of monodisperse silver nanoparticles synthesized using Ginkgo Biloba leaf extract

International Nuclear Information System (INIS)

Ren, Yan-yu; Yang, Hui; Wang, Tao; Wang, Chuang

2016-01-01

Various parts of plants can be used as a raw material for the synthesis of nanoparticles, which is eco-friendly way and does not involve any harmful chemicals. In this project, Ginkgo biloba leaf, an abundantly available medicinal plant in China, was for the first time adopted as a reducing and stabilizing agent to synthesize smaller sized and stable silver nanoparticles (AgNPs). To improve the quality of AgNPs, the reduction was accelerated by changing the concentrations of initial Ag + (0.02, 0.04, 0.06 and 0.08 mol/L) of the reaction mixture consisting of silver nitrate solution (AgNO 3 ) and Ginkgo biloba leaf extract. At pH = 8 and lower AgNO 3 concentration (0.02 mol/L), a colloid consisting of well-dispersed spherical nanoparticles was obtained. The synthesized nanocrystals were successfully characterized by UV–vis and XRD. TEM images revealed the size of the spherical AgNPs ranged between 10–16 nm. FTIR analysis revealed that biological macromolecules with groups of −NH 2 , −OH, and others were distributed on the surface of the nanoparticles. The biosynthesized AgNPs exhibited good antibacterial activities against gram-negative bacteria and gram-positive bacteria. Compared to traditional chemical methods, Ginkgo biloba leaf extract provides an easy green synthetical way. It is anticipated that the biosynthesized AgNPs can be used in areas such as cosmetics, foods and medical applications. - Highlights: • Monodisperse silver nanoparticles were first prepared by a green synthetical way through Ginkgo Biloba leaf extract. • The synthesized AgNPs is of high crystallinity, stable and good dispersion with smaller sizes between 10–16 nm. • The achieved AgNPs exhibits good antibacterial activities. • The biosynthesis method is advantageous for its cost effectiveness, availability, portability, nontoxic and environmentally benign.

Investigation of novel solid oxide fuel cell cathodes based on impregnation of SrTixFe1-xO3-δ into ceria-based backbones

DEFF Research Database (Denmark)

Brinch-Larsen, Mathias; Søgaard, Martin; Hjelm, Johan

2013-01-01

Solid oxide fuel cell (SOFC) cathodes were prepared by impregnating the nitrates corresponding to SrTixFe1-xO3-δ (STF), x= 0; 0.1; 0.2; 0.3; 0.4 and 0.5, into a porous backbone of Ce 0.9Gd0.1O2-δ (CGO). STF was chosen as very high oxygen surface exchange rate, high ionic conductivity and electroc......Solid oxide fuel cell (SOFC) cathodes were prepared by impregnating the nitrates corresponding to SrTixFe1-xO3-δ (STF), x= 0; 0.1; 0.2; 0.3; 0.4 and 0.5, into a porous backbone of Ce 0.9Gd0.1O2-δ (CGO). STF was chosen as very high oxygen surface exchange rate, high ionic conductivity...... backbone. All prepared electrodes were characterized as symmetric cells using impedance spectroscopy. Within the investigated series the infiltrate with x = 0.1 (STF10) showed the best performance with an area specific resistance (ASR) of ASR ≈ 6.4 Ω cm2 (STF10) at 600°C in air. The relatively poor...

Radiation induced structural and magnetic transformations in nanoparticle MnxZn(1−x)Fe2O4 ferrites

International Nuclear Information System (INIS)

Naik, P.P.; Tangsali, R.B.; Sonaye, B.; Sugur, S.

2015-01-01

Nanoparticle magnetic materials are suitable for multiple modern high end medical applications like targeted drug delivery, gene therapy, hyperthermia and MR thermometry imaging. Majority of these applications are confined to use of Mn–Zn ferrite nanoparticles. These nanoparticles are normally left in the body after their requisite application. Preparing these nanoparticles is usually a much involved job. However with the development of the simple technique Mn x Zn 1−x Fe 2 O 4 nanoparticles could be prepared with much ease. The nanoparticles of Mn x Zn 1−x Fe 2 O 4 with (x=1.0, 0.7, 0.5, 0.3, 0.0) were prepared and irradiated with gamma radiation of various intensities ranging between 500 R to 10,000 R, after appropriate structural and magnetic characterization. Irradiated samples were investigated for structural and magnetic properties, as well as for structural stability and cation distribution. The irradiated nanoparticles exhibited structural stability with varied cation distribution and magnetic properties, dependent on gamma radiation dose. Surprisingly samples also exhibited quenching of lattice parameter and particle size. The changes introduced in the cation distribution, lattice constant, particle size and magnetic properties were found to be irreversible with time lapse and were of permanent nature exhibiting good stability even after several months. Thus the useful properties of nanoparticles could be enhanced on modifying the cation distribution inside the nanoparticles by application of gamma radiation. - Highlights: • Mn x Zn 1−x Fe 2 O 4 nanoparticles were synthesized using auto combustion method. • The irradiated samples showed a change in cation distribution. • Lattice shrinkage observed due to radiation induced change in cation distribution. • Reduction in particle size was also observed due to gamma exposure. • An enhancement in saturation magnetization was observed in irradiated samples

Radiolytic Syntheses of Nanoparticles and Inorganic-Polymer Hybrid Microgels

International Nuclear Information System (INIS)

Chen, Q.; Shi, J.; Zhao, R.; Shen, X.

2010-01-01

In the second year of the project, we have gotten progress mainly in two directions. Firstly, for the first time, Prussian blue (PB) nanoparticles (NPs) were successfully synthesized by the partly radiolytic reduction of Fe3+ and Fe(CN)63 in the presence of poly(N-vinyl pyrrolidine) (PVP) under N2 atmospheres at room temperature. With the increase of the concentration of PVP, the size and the size distribution of the synthesized quasi-spherical PB NPs decreased obviously, leading to a hypsochromic shift on their peak position of the characteristic absorption. In the experiment, we further found that the smaller ones have a larger capacity to Cs+, suggesting that the application of PB NPs in curing thallotoxicosis may decrease the usage of PB for the patient to great extent. Secondly, through a series of preliminary experiments, we got a clear picture about the one-step radiolytic preparation of inorganic-poly(methacrylic acid-co-methyl methacrylate) hybrid microgels by surfactant-free emulsion polymerization. Besides, unpurified N-carbamothioylmethacrylamide was synthesized via the methacrylation of thiourea. These created favorable conditions for the one-step synthesis of metal sulfide-poly(methacrylic acid-co-methyl methacrylate) hybrid microgels by -irradiation and surfactant-free emulsion polymerization. (author)

Radiolytic Syntheses of Nanoparticles and Inorganic-Polymer Hybrid Microgels

Energy Technology Data Exchange (ETDEWEB)

Chen, Q.; Shi, J.; Zhao, R.; Shen, X., E-mail: qdchen@pku.edu.cn [Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, No. 5, Yiheyuan Load, Haidian District Beijing 100871 (China)

2010-07-01

In the second year of the project, we have gotten progress mainly in two directions. Firstly, for the first time, Prussian blue (PB) nanoparticles (NPs) were successfully synthesized by the partly radiolytic reduction of Fe3+ and Fe(CN)63 in the presence of poly(N-vinyl pyrrolidine) (PVP) under N2 atmospheres at room temperature. With the increase of the concentration of PVP, the size and the size distribution of the synthesized quasi-spherical PB NPs decreased obviously, leading to a hypsochromic shift on their peak position of the characteristic absorption. In the experiment, we further found that the smaller ones have a larger capacity to Cs+, suggesting that the application of PB NPs in curing thallotoxicosis may decrease the usage of PB for the patient to great extent. Secondly, through a series of preliminary experiments, we got a clear picture about the one-step radiolytic preparation of inorganic-poly(methacrylic acid-co-methyl methacrylate) hybrid microgels by surfactant-free emulsion polymerization. Besides, unpurified N-carbamothioylmethacrylamide was synthesized via the methacrylation of thiourea. These created favorable conditions for the one-step synthesis of metal sulfide-poly(methacrylic acid-co-methyl methacrylate) hybrid microgels by -irradiation and surfactant-free emulsion polymerization. (author)

The role of dysprosium on the structural and magnetic properties of (Nd_1_−_xDy_x)_2Fe_1_4B nanoparticles

International Nuclear Information System (INIS)

Rahimi, Hamed; Ghasemi, Ali; Mozaffarinia, Reza; Tavoosi, Majid

2017-01-01

In current work, Nd2Fe14B nanoparticles was synthesized by sol-gel method. Dysprosium powders were added into Nd2Fe14B nanoparticles by mechanical alloying process in order to enhancement of coercivity. The phase analysis, structure, and magnetic properties of annealed (Nd_1_−_xDy_x)_2Fe_1_4B nanoparticles with different Dy-content (x=0.1, 0.2, 0.3, 0.4, 0.5, 0.6) were investigated by employing X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, field emission scanning electron microscope, transmission electron microscope and vibrating sample magnetometer techniques. The results showed that with an increase in Dy amounts, the coercivity of particles increased from 2.9 kOe to 13.4 kOe and then decreased to 5.6 kOe. By adding an optimum amount of Dy (x=0.4), the coercivity was significantly increased from 2.9 kOe to 13.4 kOe. The average particle size of annealed (Nd_1_−_xDy_x)_2Fe_1_4B nanoparticles was below 10 nm. Magnetization reversal studies indicate that the coercivity of milled and annealed (Nd_1_−_xDy_x)_2Fe_1_4B nanoparticles is controlled by the nucleation of reversed magnetic domains. The experimental results in the angular dependence of coercivity for (Nd_1_−_xDy_x)_2Fe_1_4B permanent magnets showed that the normalized coercivity of the permanent magnets H_c(θ)/H_c(0) increases from 1 to about 1.2–1.5 with increasing θ from 0 to about π/3, for x=0.4–0.6. - Highlights: • Dy was added to Nd_2Fe_1_4B nanoparticles to improve the coercivity. • A maximum squareness ratio of 0.99 was obtained. • The average particle size decreased with an increase in Dy-content.

Synthesis, Characterization and Comparative Luminescence Studies of Rare-Earth-Doped Gd2O3 Nanoparticles

Science.gov (United States)

Pyngrope, D.; Singh, L. R.; Prasad, A. I.; Bora, A.

2018-04-01

A facile direct precipitation method was used for the synthesis of luminescence nanomaterial. Gd2O3 doped with rare earth element Eu3+ is synthesized by polyol route. The synthesized nanoparticles show their characteristic red emission. The nanoparticles are characterized by x-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and photoluminescence (PL) study. The synthesized nanoparticles are spherical particles with 30 nm size. The photoluminescence studies show the characteristic Eu3+ red emission. The PL study shows the intensity of the magnetic dipole transition ( 5 D0 \\to 7 F1 ) at 592 nm compared to that of the electronic dipole transition ( 5 D0 \\to 7 F2 ) at 615 nm. The nanomaterials can show significant application in various display devices and biomedical applications for tracking.

Rapid decolorization of textile wastewater by green synthesized iron nanoparticles.

Science.gov (United States)

Ozkan, Z Y; Cakirgoz, M; Kaymak, E S; Erdim, E

2018-01-01

The effectiveness of green tea (Camellia sinensis) and pomegranate (Punica granatum) extracts for the production of iron nanoparticles and their application for color removal from a textile industry wastewater was investigated. Polyphenols in extracts act as reducing agents for iron ions in aqueous solutions, forming iron nanoparticles. Pomegranate extract was found to have almost a 10-fold higher polyphenolic content than the same amount of green tea extract on a mass basis. However, the size of the synthesized nanoparticles did not show a correlation with the polyphenolic content. 100 ppm and 300 ppm of iron nanoparticles were evaluated in terms of color removal efficiency from a real textile wastewater sample. 300 ppm of pomegranate nanoscale zero-valent iron particles showed more than 95% color removal and almost 80% dissolved organic carbon removal. The degradation mechanisms are is considered to be adsorption and precipitation to a major extent, and mineralization to a minor extent.

Inhibition of Phytophthora parasitica and P. capsici by Silver Nanoparticles Synthesized Using Aqueous Extract of Artemisia absinthium.

Science.gov (United States)

Ali, Mohammad; Kim, Bosung; Belfield, Kevin D; Norman, David; Brennan, Mary; Ali, Gul Shad

2015-09-01

Application of nanoparticles for controlling plant pathogens is a rapidly emerging area in plant disease management, and nanoparticles synthesis methods that are economical and ecofriendly are extensively investigated. In this project, we investigated the potential of silver nanoparticles (AgNPs) synthesized with aqueous extract of Artemisia absinthium against several Phytophthora spp., which cause many economically important crop diseases. In in vitro dose-response tests conducted in microtiter plates, 10 µg ml⁻¹ of AgNPs inhibited mycelial growth of P. parasitica, P. infestans, P. palmivora, P. cinnamomi, P. tropicalis, P. capsici, and P. katsurae. Detailed in vitro dose-response analyses conducted with P. parasitica and P. capsici revealed that AgNPs synthesized with A. absinthium extract were highly potent (IC50: 2.1 to 8.3 µg ml⁻¹) and efficacious (100%) in inhibiting mycelial growth, zoospore germination, germ tube elongation, and zoospore production. Interestingly, AgNP treatment accelerated encystment of zoospores. Consistent with in vitro results, in planta experiments conducted in a greenhouse revealed that AgNP treatments prevented Phytophthora infection and improved plant survival. Moreover, AgNP in in planta experiments did not produce any adverse effects on plant growth. These investigations provide a simple and economical method for controlling Phytophthora with AgNP without affecting normal plant physiology.

Surface functionalization of microwave plasma-synthesized silica nanoparticles for enhancing the stability of dispersions

Science.gov (United States)

Sehlleier, Yee Hwa; Abdali, Ali; Schnurre, Sophie Marie; Wiggers, Hartmut; Schulz, Christof

2014-08-01

Gas phase-synthesized silica nanoparticles were functionalized with three different silane coupling agents (SCAs) including amine, amine/phosphonate and octyltriethoxy functional groups and the stability of dispersions in polar and non-polar dispersing media such as water, ethanol, methanol, chloroform, benzene, and toluene was studied. Fourier transform infrared spectroscopy showed that all three SCAs are chemically attached to the surface of silica nanoparticles. Amine-functionalized particles using steric dispersion stabilization alone showed limited stability. Thus, an additional SCA with sufficiently long hydrocarbon chains and strong positively charged phosphonate groups was introduced in order to achieve electrosteric stabilization. Steric stabilization was successful with hydrophobic octyltriethoxy-functionalized silica nanoparticles in non-polar solvents. The results from dynamic light scattering measurements showed that in dispersions of amine/phosphonate- and octyltriethoxy-functionalized silica particles are dispersed on a primary particle level. Stable dispersions were successfully prepared from initially agglomerated nanoparticles synthesized in a microwave plasma reactor by designing the surface functionalization.

Microstructural and optical properties of Ca and Cr doped cobalt ferrite nanoparticles synthesized by auto combustion

Science.gov (United States)

Agrawal, Shraddha; Parveen, Azra; Azam, Ameer

2018-05-01

The Ca and Cr doped cobalt ferrite nanoparticles (Co0.8Ca0.2) (Fe0.8 Cr0.2)2O4 were synthesized by auto combustion method. Microstructural studies were carried out by X-ray diffraction (XRD). The crystalline size of synthesized nanoparticles as determined by the XRD was found to be 17.6 nm. These structural studies suggest that the crystal system remains spinal even with the doping of calcium and chromium. Optical properties of Ca and Cr doped cobalt ferrite were studied by UV-visible technique in the range of 200-800 nm. The energy band gap was calculated with the help of Tauc relationship. Ca and Cr doped cobalt ferrite annealed at 600°C exhibit significant dispersion in complex permeability. The dielectric constant and dielectric loss of cobalt ferrite were studied as a function of frequency and were explained on the basis of Koop's theory based on Maxwell Wagner two layer models and electron hopping.

A generalized diffusion model for growth of nanoparticles synthesized by colloidal methods.

Science.gov (United States)

Wen, Tianlong; Brush, Lucien N; Krishnan, Kannan M

2014-04-01

A nanoparticle growth model is developed to predict and guide the syntheses of monodisperse colloidal nanoparticles in the liquid phase. The model, without any a priori assumptions, is based on the Fick's law of diffusion, conservation of mass and the Gibbs-Thomson equation for crystal growth. In the limiting case, this model reduces to the same expression as the currently accepted model that requires the assumption of a diffusion layer around each nanoparticle. The present growth model bridges the two limiting cases of the previous model i.e. complete diffusion controlled and adsorption controlled growth of nanoparticles. Specifically, the results show that a monodispersion of nanoparticles can be obtained both with fast monomer diffusion and with surface reaction under conditions of small diffusivity to surface reaction constant ratio that results is growth 'focusing'. This comprehensive description of nanoparticle growth provides new insights and establishes the required conditions for fabricating monodisperse nanoparticles critical for a wide range of applications. Copyright © 2013 Elsevier Inc. All rights reserved.

Gas Sensors Based on Tin Oxide Nanoparticles Synthesized from a Mini-Arc Plasma Source

Directory of Open Access Journals (Sweden)

Ganhua Lu

2006-01-01

Full Text Available Miniaturized gas sensors or electronic noses to rapidly detect and differentiate trace amount of chemical agents are extremely attractive. In this paper, we report on the fabrication and characterization of a functional tin oxide nanoparticle gas sensor. Tin oxide nanoparticles are first synthesized using a convenient and low-cost mini-arc plasma source. The nanoparticle size distribution is measured online using a scanning electrical mobility spectrometer (SEMS. The product nanoparticles are analyzed ex-situ by high resolution transmission electron microscopy (HRTEM for morphology and defects, energy dispersive X-ray (EDX spectroscopy for elemental composition, electron diffraction for crystal structure, and X-ray photoelectron spectroscopy (XPS for surface composition. Nonagglomerated rutile tin oxide (SnO2 nanoparticles as small as a few nm have been produced. Larger particles bear a core-shell structure with a metallic core and an oxide shell. The nanoparticles are then assembled onto an e-beam lithographically patterned interdigitated electrode using electrostatic force to fabricate the gas sensor. The nanoparticle sensor exhibits a fast response and a good sensitivity when exposed to 100 ppm ethanol vapor in air.

Bi2O3 nanoparticles encapsulated in surface mounted metal-organic framework thin films

Science.gov (United States)

Guo, Wei; Chen, Zhi; Yang, Chengwu; Neumann, Tobias; Kübel, Christian; Wenzel, Wolfgang; Welle, Alexander; Pfleging, Wilhelm; Shekhah, Osama; Wöll, Christof; Redel, Engelbert

2016-03-01

We describe a novel procedure to fabricate a recyclable hybrid-photocatalyst based on Bi2O3@HKUST-1 MOF porous thin films. Bi2O3 nanoparticles (NPs) were synthesized within HKUST-1 (or Cu3(BTC)2) surface-mounted metal-organic frame-works (SURMOFs) and characterized using X-ray diffraction (XRD), a quartz crystal microbalance (QCM) and transmission electron microscopy (TEM). The Bi2O3 semiconductor NPs (diameter 1-3 nm)/SURMOF heterostructures exhibit superior photo-efficiencies compared to NPs synthesized using conventional routes, as demonstrated via the photodegradation of the nuclear fast red (NFR) dye.We describe a novel procedure to fabricate a recyclable hybrid-photocatalyst based on Bi2O3@HKUST-1 MOF porous thin films. Bi2O3 nanoparticles (NPs) were synthesized within HKUST-1 (or Cu3(BTC)2) surface-mounted metal-organic frame-works (SURMOFs) and characterized using X-ray diffraction (XRD), a quartz crystal microbalance (QCM) and transmission electron microscopy (TEM). The Bi2O3 semiconductor NPs (diameter 1-3 nm)/SURMOF heterostructures exhibit superior photo-efficiencies compared to NPs synthesized using conventional routes, as demonstrated via the photodegradation of the nuclear fast red (NFR) dye. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr00532b

Influence of Al3+ substitution on the electrical resistivity and dielectric behavior of Ni0.25Cu0.20Zn0.55AlxFe2-xO4 ferrites synthesized by solid state reaction technique

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Rahman, K. R.; Chowdhury, F.-U.-Z.; Khan, M. N. I.

2017-12-01

In this paper, the effect of Al3+ substitution on the electrical and dielectric properties of Ni0.25Cu0.20Zn0.55AlxFe2-xO4 ferrites with x = 0.0, 0.05. 0.10, 0.15 and 0.20, synthesized by solid state reaction has been reported. Using two probe method, the DC resistivity has been investigated in the temperature range from 30 °C to 300 °C. Activation energy was calculated from the Arrhenius plot. The electrical conduction is explained on the basis of the hopping mechanism. The frequency dependent dielectric properties of these spinel ferrites have been studied at room temperature by measuring AC resistivity, conductivity (σac), dielectric constant and dielectric loss tangent (tan δ) in the frequency range between 1 kHz and 120 MHz. The study of dielectric properties showed that the dielectric constant and dielectric loss increased with increasing non-magnetic Al ions. The dependence of dielectric constant with frequency has been explained by Maxwell-Wagner interfacial polarization. Cole-Cole plots show semicircular arc(s) for the samples, and equivalent RC circuits have been proposed to clarify the phenomena involved therein. The analysis of complex impedance spectroscopy has been used to distinguish between the grain and grain boundary contribution to the total resistance.

Synthesis, crystal structures, fluorescence and xanthine oxidase inhibitory activity of pyrazole-based 1,3,4-oxadiazole derivatives

Science.gov (United States)

Qi, De-Qiang; Yu, Chuan-Ming; You, Jin-Zong; Yang, Guang-Hui; Wang, Xue-Jie; Zhang, Yi-Ping

2015-11-01

A series of pyrazole-based 1,3,4-oxadiazole derivatives were rationally designed and synthesized in good yields by following a convenient route. All the newly synthesized molecules were fully characterized by IR, 1H NMR and elemental analysis. Eight compounds were structurally determined by single crystal X-ray diffraction analysis. The fluorescence properties of all the compounds were investigated in dimethyl sulfoxide media. In addition, these newly synthesized compounds were evaluated for in vitro inhibitory activity against commercial enzyme xanthine oxidase (XO) by measuring the formation of uric acid from xanthine. Among the compounds synthesized and tested, 3d and 3e were found to be moderate inhibitory activity against commercial XO with IC50 = 72.4 μM and 75.6 μM. The studies gave a new insight in further optimization of pyrazole-based 1,3,4-oxadiazole derivatives with excellent fluorescence properties and XO inhibitory activity.

Synthesis of MnxGa1−xFe2O4 magnetic nanoparticles by thermal decomposition method for medical diagnosis applications

International Nuclear Information System (INIS)

Sánchez, Javier; Cortés-Hernández, Dora Alicia; Escobedo-Bocardo, José Concepción; Almanza-Robles, José Manuel; Reyes-Rodríguez, Pamela Yajaira; Jasso-Terán, Rosario Argentina; Bartolo-Pérez, Pascual; De-León-Prado, Laura Elena

2017-01-01

In this work, the synthesis of Mn x Ga 1−x Fe 2 O 4 (x=0–1) nanosized particles by thermal decomposition method, using tetraethylene glycol (TEG) as a reaction medium, has been performed. The crystalline structure of the inverse spinel obtained in all the cases was identified by X-ray diffraction (XRD). Vibration sample magnetometry (VSM) was used to evaluate the magnetic properties of ferrites and to demonstrate their superparamagnetic behavior and the increase of magnetization values due to the Mn 2+ ions incorporation into the FeGa 2 O 4 structure. Transmission electron microscopy, energy dispersive spectroscopy (TEM-EDS) and X-ray photoelectron spectroscopy (XPS) were used to characterize the obtained magnetic nanoparticles (MNPs). These MNPs showed a near spherical morphology, an average particle size of 5.6±1.5 nm and a TEG coating layer on their surface. In all the cases MNPs showed no response when submitted to an alternating magnetic field (AMF, 10.2 kA/m, 354 kHz) using magnetic induction tests. These results suggest that the synthesized nanoparticles can be potential candidates for their use in biomedical areas. - Highlights: • Superparamagnetic NPs of Mn x Ga 1−x Fe 2 O 4 were synthesized by thermal decomposition. • Saturation magnetization of MnGaFe 2 O 4 increases as Mn ions are increased. • Nanoparticles have a nanometric size of 5.6 nm and show no heating ability.

Thermal stability and electrochemical properties of PVP-protected Ru nanoparticles synthesized at room temperature

Science.gov (United States)

Kumar, Manish; Devi, Pooja; Shivling, V. D.

2017-08-01

Stable ruthenium nanoparticles (RuNPs) have been synthesized by the chemical reduction of ruthenium trichloride trihydrate (RuCl3 · 3H2O) using sodium borohydride (NaBH4) as a reductant and polyvinylpyrrolidone (PVP) as a protecting agent in the aqueous medium at room temperature. The nanoparticles thus prepared were characterized by their morphology and structural analysis from transmission electron microscopy (TEM), X-ray powder diffraction (XRD), UV-vis spectroscopy, Fourier transformation infrared and thermogravimetric analysis (TGA) techniques. The TEM image suggested a homogeneous distribution of PVP-protected RuNPs having a small average diameter of 2-4 nm with a chain-like network structure. The XRD pattern also confirmed that a crystallite size is around 2 nm of PVP-protected RuNPs having a single broad peak. The thermal stability studied using TGA, indicated good stability and the electrochemical properties of these nanoparticles revealed that saturation current increases for PVP-protected RuNPs/GC.

Magnetic properties of nanocrystalline CoFe{sub 2}O{sub 4} synthesized by thermal plasma in large scale

Energy Technology Data Exchange (ETDEWEB)

Nawale, A.B.; Kanhe, N.S. [Department of Physics, University of Pune, Pune 411007 (India); Patil, K.R. [Center for Materials Characterizations, National Chemical Laboratory, Dr. Hommi Bhabha Road, Pashan, Pune 411008 (India); Reddy, V.R.; Gupta, A. [UGC-DAE Consortium for Scientific Research, Indore Centre, University Campus, Khandwa Road, Indore 452 017 (India); Kale, B.B. [Center for Materials for Electronics Technology, Department of Information Technology, Government of India, Panchawati, Off Pashan Road, Pune 411008 (India); Bhoraskar, S.V. [Department of Physics, University of Pune, Pune 411007 (India); Mathe, V.L., E-mail: vlmathe@physics.unipune.ac.in [Department of Physics, University of Pune, Pune 411007 (India); Das, A.K. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

2012-12-14

The paper reports the large scale synthesis of nanoparticles of CoFe{sub 2}O{sub 4} using thermal plasma reactor by gas phase condensation method. The yield of formation was found to be around 15 g h{sup -1}. The magnetic properties of CoFe{sub 2}O{sub 4}, synthesized at different reactor powers, were investigated in view of studying the effect of operating parameters of plasma reactor on the structural reorganization leading to the different cation distribution. The values of saturation magnetization, coercivity and remanent magnetization were found to be influenced by input power in thermal plasma. Although the increase in saturation magnetization was marginal (61 emu g{sup -1} to 70 emu g{sup -1}) with increasing plasma power; a significant increase in the coercivity (552 Oe to 849 Oe) and remanent magnetization (16 emu g{sup -1} to 26 emu g{sup -1}) were also noticed. The Moessbauer spectra showed mixed spinel structure and canted spin order for the as synthesized nanoparticles. The detailed analysis of cation distribution using the Moessbauer spectroscopy and X-ray photoelectron spectroscopy leads to the conclusion that the sample synthesized at an optimized power shows the different site selective states. -- Highlights: Black-Right-Pointing-Pointer A rapid synthesis method for synthesizing magnetic nanoparticles of cobalt ferrite. Black-Right-Pointing-Pointer The average particle size ranges between 25 and 40 nm; as revealed by the FESEM analysis. Black-Right-Pointing-Pointer Magnetic properties are influenced by different operating parameters.

Enhanced Li-Ion Battery

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Natasha Ross

2015-01-01

Full Text Available Au with Pd nanoparticles were synthesized and coated onto the spinel LiMn2O4 via a coprecipitation calcination method with the objective to improve the microstructure, conductivity, and electrochemical activities of pristine LiMn2O4. The novel LiPdAuxMn2-xO4 composite cathode had high phase purity, well crystallized particles, and more regular morphological structures with narrow size distributions. At enlarged cycling potential ranges the LiPdAuxMn2-xO4 sample delivered 90 mAh g−1 discharge capacity compared to LiMn2O4 (45 mAh g−1. It was concluded that even a small amount of the Pd and Au enhanced both the lithium diffusivity and electrochemical conductivity of the host sample due to the beneficial properties of their synergy.

Synthesis of Nd3+doped TiO2 nanoparticles and Its Optical Behaviour

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Ezhil Arasi S.

2017-04-01

Full Text Available Pure and Rare earth ion doped TiO2 nanoparticles were synthesized by Sol-gel method. The synthesized TiO2 nanoparticles were characterized by X-ray diffraction, Raman spectroscopy, UV–Vis spectroscopy and photoluminescence emission spectra. From the UV-visible measurement, the absorption edge of Nd3+-TiO2 was shifted to a higher wavelength side with decreasing band gap. Photoluminescence emission studies reveal the energy transfer mechanism of Nd3+ doped TiO2 nanoparticles explain.

Structural investigations on differently sized monodisperse iron oxide nanoparticles synthesized by remineralization of apoferritin molecules

International Nuclear Information System (INIS)

Ullrich, Aladin; Horn, Siegfried

2013-01-01

We have investigated the structure of iron oxide nanoparticles produced by remineralization and thermal treatment of horse spleen apoferritin molecules. The described procedure allows to synthesize particles with diameters ranging from 4 to 7 nm in size. Atomic force microscopy and transmission electron microscopy (TEM) investigations were performed for shape and size determination, whereas energy-dispersive X-ray (TEM-EDX), high-resolution TEM, and electron diffraction measurements revealed the chemical composition and crystal structure of the particles. We found predominantly single crystalline nanoparticles with a hematite-like (α-Fe 2 O 3 ) structure

Photocatalytic studies of electrochemically synthesized polysaccharide-functionalized ZnO nanoparticles

Science.gov (United States)

Kaur, Simranjeet; Kaur, Harpreet

2018-05-01

The present work reports the electrochemical synthesis of polysaccharide-functionalized ZnO nanoparticles using sodium hydroxide, starch, and zinc electrodes for the degradation of cationic dye (Rhodamine-B) under sunlight. Physiochemical properties of synthesized sample have been characterized by different techniques such as XRD, TEM, FESEM, EDS, IR, and UV-visible spectroscopic techniques. The influence of various factors such as effect of dye concentration, contact time, amount of photocatalyst, and pH has been studied. The results obtained from the photodegradation study showed that degradation rate of Rhodamine-B dye has been increased with increase of amount of photocatalyst and decreased with increase in initial dye concentration. Furthermore, the kinetics of the degradation has been investigated. It has been found that the photodegradation of Rhodamine-B dye follows pseudo-first-order kinetics and prepared photocatalyst can effectively degrade the cationic dye. Thus, this ecofriendly and efficient photocatalyst can be used for the treatment of dye-contaminated water. This catalyst also showed the antibacterial activity against Bacillus pumilus and Escherichia coli bacterial strains, so the synthesized nanoparticles also have the pharmaceutical properties.

Photocatalytic activity of biogenic silver nanoparticles synthesized using potato (Solanum tuberosum) infusion.

Science.gov (United States)

Roy, Kaushik; Sarkar, C K; Ghosh, C K

2015-07-05

In this study, we have reported a fast and eco-benign procedure to synthesis silver nanoparticle at room temperature using potato (Solanum tuberosum) infusion along with the study of its photocatalytic activity on methyl orange dye. After addition of potato infusion to silver nitrate solution, the color of the mixture changed indicating formation of silver nanoparticles. Time dependent UV-Vis spectra were obtained to study the rate of nanoparticle formation with time. Purity and crystallinity of the biogenic silver nanoparticles were examined by X-ray diffraction (XRD). Average size and morphology of the nanoparticles were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Fourier transform infra-red spectroscopy (FTIR) was employed to detect functional bio-molecules responsible that contribute to the reduction and capping of biosynthesized Ag nanoparticles. Further, these synthesized nanoparticles were used to investigate their ability to degrade methyl orange dye under sunlight irradiation and the results showed effective photocatalytic property of these biogenic silver nanoparticles. Copyright © 2015 Elsevier B.V. All rights reserved.

Kinetics of 2-chlorobiphenyl Reductive Dechlorination by Pd-fe0 Nanoparticles

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Jiang Junrong

2016-01-01

Full Text Available Kinetics of 2-chlorobiphenyl (2-Cl BP catalytic reductive dechlorination by Pd-Fe0 nanoparticles were investigated. Experimental results showed that ultrafine bimetallic Pd-Fe0e nanoparticles were synthesized in the presence of 40 kHz ultrasound in order to enhance disparity and avoid agglomeration. The application of ultrasonic irradiation during the synthesis of Pd-Fe0 nanoparticles further accelerated the dechlorinated removal ratio of 2-Cl BP. Up to 95.0% of 2-Cl BP was removed after 300 min reaction with the following experimental conditions: initial 2-Cl BP concentration 10 mg L-1, Pd content 0.8 wt. %, bimetallic Pd-Fe0 nanoparticles prepared in the presence of ultrasound available dosage 7g L-1, initial pH value in aqueous solution 3.0, and reaction temperature 25°C. The catalytic reductive dechlorination of 2-Cl BP followed pseudo-first-order kinetics and the apparent pseudo-first-order kinetics constant was 0.0143 min-1.

Structural variation study of cobalt nanoparticles synthesized by co-precipitation method using 59Co NMR

Science.gov (United States)

Manjunatha, M.; Kumar, Rajeev; B. M., Siddesh; Sahoo, Balaram; Damle, R.; Ramesh, K. P.

2018-04-01

We have synthesized cobalt nanoparticles using co-precipitation method. Further, the two phases of the cobalt is monitored by varying the synthesis parameters. 59Co NMR and XRD are used as characterization tools to study the phase variation in the cobalt samples. XRD and NMR results show a remarkable correlation in the two samples (Co-1 and Co-2). Co-2 has predominant fcc and hcp phases, whereas, Co-1 has fcc phase with lower amount of hcp. Both the samples show same saturation magnetization (Ms) but there is a remarkable difference in the phase composition. Thus, 59Co NMR appears to be a good tool to identify the phase purity of the ferromagnetic cobalt samples.

Inhibition of Neuroblastoma cancer cells viability by ferromagnetic Mn doped CeO_2 monodisperse nanoparticles mediated through reactive oxygen species

International Nuclear Information System (INIS)

Abbas, Fazal; Jan, Tariq; Iqbal, Javed; Haider Naqvi, M. Sajjad; Ahmad, Ishaq

2016-01-01

Here we report the Mn doping induced effects on structural, Raman, optical, magnetic and anticancer properties of CeO_2 nanoparticles prepared via soft chemical route. Structural and microstructural results infer that the synthesized nanoparticles have single phase cubic fluorite structure of CeO_2 and that Mn doping results in enhancement of the structural defects. Scanning electron microscopy results reveal the formation of monodisperse nanoparticles having average particle size ranging from 30 to 41 nm. The optical absorbance spectroscopy analysis discloses the band gap energy tailoring of CeO_2 nanoparticles via Mn doping. Room temperature ferromagnetism (RTFM) has been found in both as-prepared and Mn doped CeO_2 nanoparticles. This RTFM of the synthesized nanoparticles have been attributed to the Mn ions and surface defects such as oxygen vacancies. Finally, the influence of Mn dopant on the cell viability and reactive oxygen species (ROS) generation levels of CeO_2 nanoparticles in the presence of healthy and cancerous cells have been studied. It has been observed that the differential cytotoxicity of the synthesized nanoparticles is strongly correlated with level of ROS generation. - Highlights: • Mn doped CeO_2 nanoparticles with cubic fluorite structure were synthesized. • Mn dopant significantly tailored the band gap of CeO_2 nanoparticles. • The synthesized nanoparticles exhibited room temperature ferromagnetic behavior. • The cytotoxicity of these nanoparticles was reported for the first time. • The synthesized nanoparticles exhibited differential cytotoxicity.

Study of magnetic behavior in hexagonal-YMn{sub 1−x}Fe{sub x}O{sub 3} (x=0 and 0.2) nanoparticles using remanent magnetization curves

Energy Technology Data Exchange (ETDEWEB)

Chauhan, Samta; Singh, Amit Kumar; Srivastava, Saurabh Kumar; Chandra, Ramesh, E-mail: ramesfic@iitr.ac.in

2016-09-15

We have studied the magnetic behavior of YMn{sub 1−x}Fe{sub x}O{sub 3} (x=0 and 0.2) nanoparticles synthesized by conventional solid state reaction method. The as-synthesized nanoparticles were found to have hexagonal phase with P6{sub 3cm} space group confirmed by X-Ray diffraction. The particle size was found to be ~70 nm as confirmed by both X-Ray diffraction and Transmission Electron Microscopy. DC magnetization and memory effect measurements imply that the h-YMnO{sub 3} nanoparticles bear a resemblance to super spin-glass state following de Almeida–Thouless like behavior which is being suppressed by Fe-doping. The Fe-doping in YMnO{sub 3} enhances the antiferromagnetic (AFM) transition temperature T{sub N} to ~79 K and induces a new magnetic state due to the surface spins which is realized as diluted antiferromagnet in a field (DAFF) as explored by the thermoremanent and isothermoremanent magnetization measured with different applied magnetic field. - Highlights: • Magnetic behavior of h-YMn{sub 1−x}Fe{sub x}O{sub 3} (x=0 and 0.2) nanoparticles have been studied. • The nanoparticles (~70 nm) were synthesized by solid state reaction method. • Magnetic data reveal spin-glass behavior in YMnO{sub 3} which was suppressed in YMn{sub 0.8}Fe{sub 0.2}O{sub 3}. • The h-YMnO{sub 3} nanoparticles show memory effect and obey de-Almeida Thouless line. • TRM and IRM suggest spin glass nature for YMnO{sub 3}, while the YMn{sub 0.8}Fe{sub 0.2}O{sub 3} resembles DAFF.

Sonochemically synthesized biocompatible zirconium phosphate nanoparticles for pH sensitive drug delivery application.

Science.gov (United States)

Kalita, Himani; Prashanth Kumar, B N; Konar, Suraj; Tantubay, Sangeeta; Kr Mahto, Madhusudan; Mandal, Mahitosh; Pathak, Amita

2016-03-01

The present work reports the synthesis of biocompatible zirconium phosphate (ZP) nanoparticles as nanocarrier for drug delivery application. The ZP nanoparticles were synthesized via a simple sonochemical method in the presence of cetyltrimethylammonium bromide and their efficacy for the delivery of drugs has been tested through various in-vitro experiments. The particle size and BET surface area of the nanoparticles were found to be ~48 nm and 206.51 m(2)/g respectively. The conventional MTT assay and cellular localization studies of the particles, performed on MDA-MB-231 cell lines, demonstrate their excellent biocompatibility and cellular internalization behavior. The loading of curcumin, an antitumor drug, onto the ZP nanoparticles shows the rapid drug uptake ability of the particles, while the drug release study, performed at two different pH values (at 7.4 and 5) depicts pH sensitive release-profile. The MTT assay and cellular localization studies revealed higher cellular inhibition and better bioavailability of the nanoformulated curcumin compared to free curcumin. Copyright © 2015 Elsevier B.V. All rights reserved.

Structures and electron affinity of XO30,-, XOF40,- and XO2F20,- (X = P, As, Sb, Bi): a theoretical study of novel superhalogen formulae and exceptions of superhalogen formulae

Science.gov (United States)

Yang, Yi-Fan; Cui, Zhong-Hua; Ding, Yi-Hong

2015-03-01

Most superhalogen species are in the form of oxides or halides. To enrich the family of superhalogen species, herein, we investigated the structures and electron affinity (EA) values of higher group 15 elements (X = P, As, Sb, Bi) oxyfluoride species XO30,-, XOF40,- and XO2F20,-, at the CCSD(T)/aug-cc-pVTZ-pp & aug-cc-pVTZ //B3LYP/aug-cc-pVTZ-pp & aug-cc-pVTZ levels (aug-cc-pVTZ-pp for X = Sb and Bi). Some oxyfluoride species, i.e., PO2F20,-, AsO2F20,-, SbO2F20,-, POF40,-, AsOF40,-, SbOF40,- and BiOF40,-, were found to possess higher EA (VDE: 5.0-6.2 eV; ADE: 4.5-5.5 eV) than halogens (F: 3.4 eV; Cl: 3.6 eV). Thus, we recommended that the oxyfluorides in the form of XO2F20,- and XOF40,- should be considered as potential superhalogens, which have not been considered previously. Surprisingly, we showed that BiO3 and BiO2F2, in superhalogen formulae, possess a high vertical detachment energy (VDE) yet a low adiabatic detachment energy (ADE). This is in marked contrast to the previously reported superhalogens, which generally contain both the high VDE and high ADE values. It is the first report about exceptions of superhalogen formulae. These findings revealed that for the analogous main-group compounds with the same structural formula, the difference in the metallic property of the core element could lead to the significant difference in the ground structures of either the anionic or neutral structures, which would result in the much differed superhalogen features.

Evaluation of plant-mediated synthesized silver nanoparticles against vector mosquitoes.

Science.gov (United States)

Veerakumar, Kaliyan; Govindarajan, Marimuthu; Hoti, S L

2014-12-01

Diseases transmitted by blood-feeding mosquitoes, such as dengue fever, dengue hemorrhagic fever, Japanese encephalitis, malaria, and filariasis, are increasing in prevalence, particularly in tropical and subtropical zones. To control mosquitoes and mosquito-borne diseases, which have worldwide health and economic impacts, synthetic insecticide-based interventions are still necessary, particularly in situations of epidemic outbreak and sudden increases of adult mosquitoes. Green nanoparticle synthesis has been achieved using environmentally acceptable plant extract and eco-friendly reducing and capping agents. In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, in the present study, the adulticidal activity of silver nanoparticles (AgNPs) synthesized using Heliotropium indicum plant leaf extract against adults of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus was determined. Adult mosquitoes were exposed to varying concentrations of aqueous extract of H. indicum and synthesized AgNPs for 24 h. AgNPs were rapidly synthesized using the leaf extract of H. indicum, and the formation of nanoparticles was observed within 6 h. The results recorded from UV-vis spectrum, Fourier transform infrared, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy support the biosynthesis and characterization of AgNPs. The maximum efficacy was observed in synthesized AgNPs against the adult of A. stephensi (lethal dose (LD)₅₀ = 26.712 μg/mL; LD₉₀ = 49.061 μg/mL), A. aegypti (LD₅₀ = 29.626 μg/mL; LD₉₀ = 54.269 μg/mL), and C. quinquefasciatus (LD₅₀ = 32.077 μg/mL; LD₉₀ = 58.426 μg/mL), respectively. No mortality was observed in the control. These results suggest that the leaf aqueous extracts of H.indicum and green synthesis of AgNPs have the potential to be used as an ideal eco-friendly approach for the control of

Perovskite oxides La0.4Sr0.6CoxMn1-xO3 (x = 0, 0.2, 0.4 as an effective electrocatalyst for lithium—air batteries

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Yajun Zhao

2018-01-01

Full Text Available Co-doped perovskite oxide La0.4Sr0.6CoxMn1-xO3 (x = 0, 0.2, 0.4 composites are prepared by sol–gel method utilizing citric acid as chelating agent. These composites show good catalytic activities when tested as catalysts rechargeable lithium—air batteries. In particular, the La0.4Sr0.6Co0.4Mn0.6O3 shows a lower potential gap. When these samples are tested as catalysts for Li—air batteries at a current density of 100 mA g−1, the discharge capacities with different La0.4Sr0.6CoxMn1-xO3 (x = 0, 0.2, 0.4 catalysts are 5819, 6420, and 7227 mA h g−1, respectively. In addition, under a capacity limitation of 1000 mA h g−1, the cell using La0.4Sr0.6Co0.4Mn0.6O3 as catalyst shows good cycling stability up to 46 cycles. The good electrochemical performance suggests that suitable doping of Co in Mn site of La0.4Sr0.6MnO3 could be a promising route to improve the catalytic activity.

Influence of pH on structural morphology and magnetic properties of ordered phase cobalt doped lithium ferrites nanoparticles synthesized by sol-gel method

International Nuclear Information System (INIS)

Srivastava, Manish; Ojha, Animesh K.; Chaubey, S.; Sharma, Prashant K.; Pandey, Avinash C.

2010-01-01

Cobalt doped lithium ferrite nanoparticles were synthesized at different pH by sol-gel method. The effect of pH on the physical properties of cobalt doped lithium ferrite nanoparticles has been investigated. The nanoparticles synthesized at different pH were characterized through X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Raman spectroscopy (RS), Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and vibrating sample magnetometer (VSM). The XRD patterns were analyzed to determine the crystal phase of cobalt doped lithium ferrites nanoparticles synthesized at different pH. The XRD results show the formation of impurity free cobalt doped lithium ferrites having ordered phase spinel structure. A similar kind of conclusion was also drawn through the analysis of Raman spectra of the nanoparticles synthesized at different pH. SEM micrographs show that the structural morphology of the nanoparticles is highly sensitive to the pH during the synthesis process. The magnetic properties such as; saturation magnetization (Ms), remnant magnetization (Mr) and coercivety (Hc) have been also investigated and found to be different for the nanoparticles synthesized at different pH, which may be attributed to the different size and surface morphology of the nanoparticles.

Antimicrobial, Antioxidant and Cytotoxic Activity of Silver Nanoparticles Synthesized by Leaf Extract of Erythrina suberosa (Roxb.).

Science.gov (United States)

Mohanta, Yugal K; Panda, Sujogya K; Jayabalan, Rasu; Sharma, Nanaocha; Bastia, Akshaya K; Mohanta, Tapan K

2017-01-01

In this experiment, biosynthesized silver nanoparticles (AgNPs) were synthesized using aqueous leaf extract of Erythrina suberosa (Roxb.). The biosynthesis of silver nanoparticle was continuously followed by UV-vis spectrophotometric analysis. The response of the phytoconstituents resides in E. suberusa during synthesis of stable AgNPs were analyzed by ATR- fourier-transform infrared spectroscopy. Further, the size, charge, and polydispersity nature of AgNPs were studied using dynamic light scattering spectroscopy. The morphology of the nanoparticles was determined by scanning electron microscopy. Current result shows core involvement of plant extracts containing glycosides, flavonoids, and phenolic compounds played a crucial role in the biosynthesis of AgNPs. The antimicrobial activities of silver nanoparticles were evaluated against different pathogenic bacterium and fungi. The antioxidant property was studied by radical scavenging (DPPH) assay and cytotoxic activity was evaluated against A-431 osteosarcoma cell line by MTT assay. The characteristics of the synthesized silver nanoparticles suggest their application as a potential antimicrobial and anticancer agent.

Investigations on structural and electrical parameters of p-Si/ MgxZn1-xO thin film heterojunction diodes grown by RF magnetron sputtering technique

Science.gov (United States)

Singh, Satyendra Kumar; Hazra, Purnima

2018-05-01

This work reports fabrication and characterization of p-Si/ MgxZn1-xO thin film heterojunction diodes grown by RF magnetron sputtering technique. In this work, ZnO powder was mixed with MgO powder at per their weight percentage from 0 to 10% to prepare MgxZn1-xO target. The microstructural, surface morphological and optical properties of as-deposited p-Si/MgxZn1-xO heterostructure thin films have been studied using X-ray Diffraction, atomic force microscopy and variable angle ellipsometer. XRD spectra exhibit that undoped ZnO thin films has preferred crystal orientation in (002) plane. However, with increase in Mg-doping, ZnO (101) crystal plane is enhanced progressively due to phase segregation, even though preferred growth orientation of ZnO crystals is still towards (002) plane. The electrical characteristics of Si/ MgxZn1-xO heterojunction diodes with large area Al/Ti ohmic contacts are evaluated using semiconductor parameter analyzer. With rectification ratio of 27894, reverse saturation current of 20.5 nA and barrier height of 0.724 eV, Si/Mg0.5Zn0.95O thin film heterojunction diode is believed to have potential to be used in wider bandgap nanoelectronic device applications.

Crystallization-mediated amorphous Cu{sub x}O (x = 1, 2)/crystalline CuI p–p type heterojunctions with visible light enhanced and ultraviolet light restrained photocatalytic dye degradation performance

Energy Technology Data Exchange (ETDEWEB)

Wang, Hongli; Cai, Yun; Zhou, Jian; Fang, Jun, E-mail: fangjun@njtech.edu.cn; Yang, Yang, E-mail: yangy@njtech.edu.cn

2017-04-30

Highlights: • Cu{sub x}O(x = 1, 2)/CuI p–p type heterojunctions were facilely constructed via crystallization-mediated approaches. • Cu{sub x}O/CuI heterojunctions exhibit effective visible-light-driven photocatalytic activity for dye degradation. • The Cu{sub x}O/CuI interface can enhance the spatial separation of the photogenerated electron–hole pairs. • This work represents a critical step for mass production of functional semiconductor heterojunctions in a mild manner. - Abstract: We report simple and cost-effective fabrication of amorphous Cu{sub x}O (x = 1, 2)/crystalline CuI p–p type heterojunctions based on crystallization-mediated approaches including antisolvent crystallization and crystal reconstruction. Starting from CuI acetonitrile solution, large crystals in commercial CuI can be easily converted to aggregates consisting of small particles by the crystallization processes while the spontaneous oxidation of CuI by atmospheric/dissolved oxygen can induce the formation of trace Cu{sub x}O on CuI surface. As a proof of concept, the as-fabricated Cu{sub x}O/CuI heterojunctions exhibit effective photocatalytic activity towards the degradation of methyl blue and other organic pollutants under visible light irradiation, although the wide band-gap semiconductor CuI is insensible to visible light. Unexpectedly, the Cu{sub x}O/CuI heterojunctions exhibit restrained photocatalytic activity when ultraviolet light is applied in addition to the visible. It is suggested that the Cu{sub x}O/CuI interface can enhance the spatial separation of the electron–hole pairs with the excitation of Cu{sub x}O under visible light and prolong the lifetime of photogenerated charges with high redox ability. The present work represents a critically important step in advancing the crystallization technique for potential mass production of semiconductor heterojunctions in a mild manner.

Antibacterial Activity of Silver Nanoparticles Synthesized by Using Extracts of Hedera helix

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Ahmadreza Abbasifar

2017-01-01

Full Text Available Background Silver nanoparticles (AgNPs are one of the most widely applicable particles whose application is increasing in Nano world daily. Silver nanoparticles have expressed significant advances owing to wide range of applications in the field of bio-medical, sensors, antimicrobials, catalysts, electronics, optical fibers, agricultural, bio-labeling and the other areas. Green synthesis is the safe and easiest method of producing silver nanoparticles. Because of the production of the silver ions, silver nanoparticles are found to have the antibacterial activity. Objectives The aim of this study was to investigate antibacterial activity of silver nanoparticles synthesized by using extracts of Hedera helix against Bacillus subtilis and Klebsiella pneumoniae. Methods In this experimental study AgNPs were prepared by the reaction of 1mM silver nitrate and extracts of Hedera helix. Antibacterial activity of AgNPs was assessed by using disc diffusion method against Bacillus subtilis and Klebsiella pneumoniae. The AgNPs were characterized by UV-visible (vis spectrophotometer, particle size analyzer by dynamic light scattering (DLS method, transmission electron microscopy (TEM. Results AgNPs obtained showed significantly higher antimicrobial activities against B. subtilis and K. pneumonia in comparison to both AgNO3 and raw plant extracts. Conclusions Biological methods are a good competent for the chemical procedures, which are environment friendly and convenient.

In Vivo toxicological assessment of biologically synthesized silver nanoparticles in adult Zebrafish (Danio rerio)

Energy Technology Data Exchange (ETDEWEB)

Krishnaraj, Chandran, E-mail: krishnarajbio@gmail.com [Department of Food Science & Technology, College of Agriculture & Life Sciences, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Harper, Stacey L. [Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331 (United States); Yun, Soon-Il, E-mail: siyun@jbnu.ac.kr [Department of Food Science & Technology, College of Agriculture & Life Sciences, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

2016-01-15

Highlights: • Synthesis of AgNPs achieved using Malva crispa Linn., leaves extract. • 96 h LC{sub 50} concentration of AgNPs was observed at 142.2 μg/l in adult zebrafish. • Cytological changes and intrahepatic localization of AgNPs were demonstrated in tissues. • Presence of micronuclei and nuclear abnormalities were observed. • The mRNA expression of stress and immune response related genes were analyzed. - Abstract: The present study examines the deleterious effect of biologically synthesized silver nanoparticles in adult zebrafish. Silver nanoparticles (AgNPs) used in the study were synthesized by treating AgNO{sub 3} with aqueous leaves extract of Malva crispa Linn., a medicinal herb as source of reductants. LC{sub 50} concentration of AgNPs at 96 h was observed as 142.2 μg/l. In order to explore the underlying toxicity mechanisms of AgNPs, half of the LC{sub 50} concentration (71.1 μg/l) was exposed to adult zebrafish for 14 days. Cytological changes and intrahepatic localization of AgNPs were observed in gills and liver tissues respectively, and the results concluded a possible sign for oxidative stress. In addition to oxidative stress the genotoxic effect was observed in peripheral blood cells like presence of micronuclei, nuclear abnormalities and also loss in cell contact with irregular shape was observed in liver parenchyma cells. Hence to confirm the oxidative stress and genotoxic effects the mRNA expression of stress related (MTF-1, HSP70) and immune response related (TLR4, NFKB, IL1B, CEBP, TRF, TLR22) genes were analyzed in liver tissues and the results clearly concluded that the plant extract mediated synthesis of AgNPs leads to oxidative stress and immunotoxicity in adult zebrafish.

High stable suspension of magnetite nanoparticles in ethanol by using sono-synthesized nanomagnetite in polyol medium

International Nuclear Information System (INIS)

Bastami, Tahereh Rohani; Entezari, Mohammad H.

2013-01-01

Graphical abstract: - Highlights: • The sonochemical synthesis of magnetite nanoparticles was carried out in EG without any surfactant. • The nanoparticles with sizes ∼24 nm were composed of small building blocks with sizes ∼2 nm. • The hydrophilic magnetite nanoparticles were stable in ethanol even after 8 months. • Ultrasonic intensity showed a crucial role on the obtained high stable magnetite nanoparticles in ethanol. - Abstract: The sonochemical synthesis of magnetite nanoparticles was carried out at relatively low temperature (80 °C) in ethylene glycol (EG) as a polyol solvent. The particle size was determined by transmission electron microscopy (TEM). The magnetite nanoparticles with an average size of 24 nm were composed of small building blocks with an average size of 2–3 nm and the particles exhibited nearly spherical shape. The surface characterization was investigated by using Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The stability of magnetite nanoparticles was studied in ethanol as a polar solvent. The nanoparticles showed an enhanced stability in ethanol which is due to the hydrophilic surface of the particles. The colloidal stability of magnetite nanoparticles in ethanol was monitored by UV–visible spectrophotometer. According to the results, the nanoparticles synthesized in 30 min of sonication with intensity of 35 W/cm 2 (50%) led to a maximum stability in ethanol as a polar solvent with respect to the other applied intensities. The obtained magnetite nanoparticles were stable for more than12 months

Mn2+ anchored CdS polymer nanocomposites: An efficient alternative for Mn2+ doped CdS nanoparticles

International Nuclear Information System (INIS)

Saikia, Bhaskar Jyoti; Nath, Bikash Chandra; Borah, Chandramika; Dolui, Swapan Kumar

2015-01-01

A chelating bi-functional polymer brushes was prepared via atom transfer radical polymerization using grafting-from methodology. Mn 2+ -anchored CdS-polymer nanocomposites were synthesized using this graft copolymer by simple chelation method resulting in emission at about 620 nm which originates from the fluorescence of manganese ions embedded on the surface of CdS nanoparticles. This method provides an efficient straightforward substitute of Mn 2+ dopped CdS nanoparticles. Optical properties of the composites were investigated which indicates that simple Mn 2+ chelation and subsequent binding of CdS in a polymer matrix can have similar effect in the luminescence property as those synthesized via complex doping methods. Moreover this methodology can be applied for synthesis of any metal anchored nanocomposites proficiently and cost effectively in large-scale production. - Highlights: • A chelating bifunctional copolymer brush was synthesized via ATRP. • CdS nanoparticles and Mn 2+ were coupled with the bifunctional polymer. • Composites showed emission properties similar to Mn 2+ doped CdS nanoparticles. • Side chain length of the polymers also affect the emission properties of the composites.

In vitro anticancer potential of BaCO3 nanoparticles synthesized via green route.

Science.gov (United States)

Nagajyothi, P C; Pandurangan, Muthuraman; Sreekanth, T V M; Shim, Jaesool

2016-03-01

Green synthesis of nanoparticles is a growing research area because of their potential applications in nanomedicine. Barium carbonate nanoparticles (BaCO3 NPs) were synthesized using an aqueous extract of Mangifera indica seed as a reducing agent. These particles were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Transmission electron microscopy (TEM), selected area electron diffraction (SAED), Energy-dispersive-X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analysis. HR-TEM images are confirmed that green synthesized BaCO3 NPs have spherical, triangular and uneven shapes. EDX analysis confirmed the presence of Ba, C and O. The peaks at 2θ of 19.45, 23.90, 24.29, 27.72, 33.71, 34.08, 34.60, 41.98, 42.95, 44.18, 44.85, and 46.78 corresponding to (110), (111), (021), (002), (200), (112), (130), (221), (041), (202), (132) and (113) showed that BaCO3 NPs average size was ~18.3 nm. SAED pattern confirmed that BaCO3 NPs are crystalline nature. BaCO3 NPs significantly inhibited cervical carcinoma cells, as evidenced by cytotoxicity assay. Immunofluorescence and fluorescence assays showed that BaCO3 NPs increased the expression and activity of caspase-3, an autocatalytic enzyme that promotes apoptosis. According to the results, green synthesis route has great potential for easy, rapid, inexpensive, eco-friendly and efficient development of novel multifunctional nanoparticles for the treatment of cancer. Copyright © 2016 Elsevier B.V. All rights reserved.

XANES studies of titanium dioxide nanoparticles synthesized by using Peltophorum pterocarpum plant extract

Energy Technology Data Exchange (ETDEWEB)

Saravanan, S. [Centre for Photonics and Nanotechnology, Sona College of Technology, Salem 636005, Tamilnadu (India); Balamurugan, M., E-mail: chem.muruga@gmail.com [Centre for Photonics and Nanotechnology, Sona College of Technology, Salem 636005, Tamilnadu (India); Lippitz, A. [Bundesanstalt für Materialforschung und -prüfung, 6.8 Oberflächenanalytik und Grenzflächenchemie Unter den Eichen 44 – 46, 12203, Berlin (Germany); Fonda, E.; Swaraj, S. [Synchrotron SOLEIL, L’ormes des merisiers, Saint Aubin BP-48, 91192, Gif-Sur-Yvette Cedex (France)

2016-12-15

The preparation and characterization of a Titanium dioxide (TiO{sub 2}) by a simple, cost effective, facile and eco-friendly green synthesis method using Peltophorum pterocarpum plant extract is presented. The green synthesized nanoparticles were characterized using X-ray diffraction (XRD), Raman spectroscopy, High-resolution transmission electron microscopy (HR-TEM) and X-ray absorption near edge spectroscopy (XANES). XRD results show that the prepared TiO{sub 2} NPs were significantly crystalline with various percentages of anatase and rutile phases. The nanoparticles were found to have different diameters ranging from 20 to 80 nm. No evidence of any intermediate or different TiO{sub 2} phases were found in XANES measurements performed at the Ti K- and L-edge. It is shown that the TiO{sub 2} NPs with high uniformity, high surface area and minimum aggregation can be prepared with relative ease and the desired anatase: rutile phase ratio can be obtained by controlling the experimental conditions.