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Catalyst Recovery and Recycling Facilitated by Magnetic Separation: Iridium and Other Metal Nanoparticles

Jacinto, Marcos J.; Silva, Fernanda P.; Kiyohara, Pedro Kunihiko; Landers, Richard; Rossi, Liane M.
Fonte: WILEY-V C H VERLAG GMBH; WEINHEIM Publicador: WILEY-V C H VERLAG GMBH; WEINHEIM
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.26%
The immobilization of metal nanoparticles in magnetic responsive solids allows the easy, fast, and clean separation of catalysts; however, the efficiency of this separation process depends on a strong metalsupport interaction. This interaction can be enhanced by functionalizing the support surface with amino groups. Our catalyst support contains an inner core of magnetite that enables the magnetic separation from liquid systems and an external surface of silica suitable for further modification with organosilanes. We report herein that a magnetically recoverable amino-functionalized support captured iridium species from liquid solutions and produced a highly active hydrogenation catalyst with negligible metal leaching. An analogous Ir0 catalyst prepared with use of a nonfunctionalized support shows a higher degree of metal leaching into the liquid products. The catalytic performance in the hydrogenation of alkenes is compared with that of Rh and Pt catalysts.; INCT-Catalise; INCTCatalise; Brazilian government agency FAPESP; Brazilian government agency FAPESP; Brazilian government agency CNPq; Brazilian government agency CNPq

Synthesis of supported metal nanoparticle catalysts using ligand assisted methods

Costa, Natália J. S.; Rossi, Liane M.
Fonte: ROYAL SOC CHEMISTRY; CAMBRIDGE Publicador: ROYAL SOC CHEMISTRY; CAMBRIDGE
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.38%
The synthesis and characterization methods of metal nanoparticles (NPs) have advanced greatly in the last few decades, allowing an increasing understanding of structure-property-performance relationships. However, the role played by the ligands used as stabilizers for metal NPs synthesis or for NPs immobilization on solid supports has been underestimated. Here, we highlight some recent progress in the preparation of supported metal NPs with the assistance of ligands in solution or grafted on solid supports, a modified deposition-reduction method, with special attention to the effects on NPs size, metal-support interactions and, more importantly, catalytic activities. After presenting the general strategies in metal NP synthesis assisted by ligands grafted on solid supports, we highlight some recent progress in the deposition of pre-formed colloidal NPs on functionalized solids. Another important aspect that will be reviewed is related to the separation and recovery of NPs. Finally, we will outline our personal understanding and perspectives on the use of supported metal NPs prepared through ligand-assisted methods.; FAPESP; CAPES; CNPq; INCT-Catalise

Surface modification by metal ion implantation forming metallic nanoparticles in insulating matrix.

Salvadori, Maria Cecilia Barbosa da Silveira; Teixeira, Fernanda de Sá; Sgubin, Leonardo Gimenes; Cattani, Mauro Sergio Dorsa; Brown, I. G.
Fonte: Kusadasi Publicador: Kusadasi
Tipo: Aula
Português
Relevância na Pesquisa
46.45%
There is special interest in the incorporation of metallic nanoparticles in a surrounding dielectric matrix for obtaining composites with desirable characteristics such as for surface plasmon resonance, which can be used in photonics and sensing, and controlled surface electrical conductivity. We investigated nanocomposites produced through metallic ion implantation in insulating substrate, where the implanted metal self-assembles into nanoparticles. During the implantation, the excess of metal atom concentration above the solubility limit leads to nucleation and growth of metal nanoparticles, driven by the temperature and temperature gradients within the implanted sample including the beam-induced thermal characteristics. The nanoparticles nucleate near the maximum of the implantation depth profile (projected range), that can be estimated by computer simulation using the TRIDYN. This is a Monte Carlo simulation program based on the TRIM (Transport and Range of Ions in Matter) code that takes into account compositional changes in the substrate due to two factors: previously implanted dopant atoms, and sputtering of the substrate surface. Our study suggests that the nanoparticles form a bidimentional array buried few nanometers below the substrate surface. More specifically we have studied Au/PMMA (polymethylmethacrylate)...

Nanopartículas metálicas anisotrópicas : mecanismos de formação e aplicações ópticas; Anisotropic metal nanoparticles : formation mechanisms and optical applications

Túlio Costa Rizuti da Rocha
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 12/03/2008 Português
Relevância na Pesquisa
56.21%
Nanopartículas de metais nobres têm atraído uma renovada atenção nos últimos anos devido às novas aplicações científicas e tecnológicas explorando suas propriedades ópticas únicas. No regime nanométrico, é bem conhecido que a resposta óptica de metais, associada aos plásmons de superfície, depende fortemente do tamanho e também da forma. De fato, grande parte das aplicações ópticas de nanopartículas de ouro e prata baseia-se na exploração dos efeitos de forma. Porém, apesar dos esforços realizados, os processos que levam à formação de morfologias anisotrópicas ainda não são bem compreendidos e a formulação de um mecanismo geral ainda é um desafio. Nesse trabalho, foram abordados os mecanismos de formação e crescimento de nanoprismas triangulares de prata produzidos por métodos de síntese coloidal. Uma combinação de diferentes técnicas experimentais foi utilizada para estudar diversos aspectos da síntese fotoquímica, dentre eles, a evolução morfológica, a cinética da reação e a estrutura cristalina das nanopartículas. As sólidas evidências experimentais obtidas associadas a outras observações da literatura foram utilizadas na formulação de um modelo fenomenológico para explicar a formação e crescimento dos nanoprismas de prata em métodos fotoquímicos. Esse modelo baseia-se na influência dos defeitos cristalográficos...

Membrana densa de quitosana contendo nanopartículas de cobre : caracterização e possíveis aplicações; Chitosan membrane containing copper nanoparticles : characterization and possible applications

Fernanda Condi de Godoi
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Português
Relevância na Pesquisa
46.46%
Dentre os biopolímeros que têm maior capacidade em formar complexos metálicos, a quitosana (QUI) ocupa posição de destaque. Os materiais feitos de quitosana-metal podem ter aplicações em diferentes campos, tais como: na engenharia ambiental, na medicina, na catálise e até no desenvolvimento de biosensores. A quitosana pode atuar como um agente redutor e estabilizante de nanopartículas metálicas. O presente estudo aborda o tema que envolve o estudo de nanopartículas metálicas tendo como suporte quitosana. Escolheu-se como metal o cobre, pois a adsorção deste pela quitosana já é bem conhecida pela comunidade científica. Neste contexto, objetivou-se: (1) Sintetizar e caracterizar membrana QUI contendo nanopartículas de cobre; (2) avaliar o comportamento higroscópico e a (3) influência da presença de nanopartículas de cobre na adsorção de Cr(VI) e V(V) em membrana QUI. As nanopartículas de cobre foram sintetizadas pela reação de oxi-redução entre os cátions Cu(II), adsorvidos previamente à membrana de quitosana, e o agente redutor NaBH4. Verificou-se, por meio da técnica Espectroscopia de Absorção de Raios X Dispersiva (DXAS), que ao final do processo de redução as espécies de cobre eram compostas por 63% de Cu(0) e 37% de Cu(I). O comportamento higroscópico das membranas de quitosana com e sem cobre foi avaliado por curvas isotérmicas (25 °C) de sorção de água em equipamento DVS. As curvas foram analisadas pelo Modelo GAB e pela teoria de Zimm-Lundberg. De acordo com a segunda teoria...

Catalyst Recovery and Recycling Facilitated by Magnetic Separation: Iridium and Other Metal Nanoparticles

Jacinto, Marcos J.; Silva, Fernanda P.; Kiyohara, Pedro K.; Landers, Richard; Rossi, Liane M.
Fonte: Wiley-Blackwell; Weinheim Publicador: Wiley-Blackwell; Weinheim
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.26%
The immobilization of metal nanoparticles in magnetic responsive solids allows the easy, fast, and clean separation of catalysts; however, the efficiency of this separation process depends on a strong metalsupport interaction. This interaction can be enhanced by functionalizing the support surface with amino groups. Our catalyst support contains an inner core of magnetite that enables the magnetic separation from liquid systems and an external surface of silica suitable for further modification with organosilanes. We report herein that a magnetically recoverable amino-functionalized support captured iridium species from liquid solutions and produced a highly active hydrogenation catalyst with negligible metal leaching. An analogous Ir0 catalyst prepared with use of a nonfunctionalized support shows a higher degree of metal leaching into the liquid products. The catalytic performance in the hydrogenation of alkenes is compared with that of Rh and Pt catalysts.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The coordination chemistry at gold nanoparticles

Toma,Henrique E.; Zamarion,Vitor M.; Toma,Sergio H.; Araki,Koiti
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 Português
Relevância na Pesquisa
46.42%
In gold nanoparticles the surface metal atoms play a major role, determining their chemical and physical properties by interacting with donor-acceptor species or ligands in a similar way as the related metal complexes. In addition, coherent oscillations of the metal electrons in resonance with the frequency of the exciting light give rise to localized surface plasmons responsible for an enhancement of the local electric field and SERS effect, allowing a wide range of applications in chemistry, biology and nanotechnology. Multifunctional bridging ligands can be employed for simultaneously binding metal ions and surface atoms. The attractive point of this approach is the possibility of exploiting the charge controlled stabilization by the metal complexes, while imparting new characteristics and properties to the modified nanoparticles. As a matter of fact, a new, exciting field of coordination chemistry can be envisaged, combining metal nanoparticles and metal complexes, in the light of supramolecular and surface plasmon resonance effects.

Metal nanoparticles/ionic liquid/cellulose: polymeric membrane for hydrogenation reactions

Gelesky,Marcos Alexandre; Scheeren,Carla Weber
Fonte: Associação Brasileira de Polímeros Publicador: Associação Brasileira de Polímeros
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 Português
Relevância na Pesquisa
56.24%
Rhodium and platinum nanoparticles were supported in polymeric membranes with 10, 20 and 40 µm thickness. The polymeric membranes were prepared combining cellulose acetate and the ionic liquid (IL) 1-n-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide (BMI.(NTf)2. The presence of metal nanoparticles induced an increase in the polymeric membrane surface areas. The increase of the IL content resulted in an improvement of elasticity and decrease in tenacity and toughness, whereas the stress at break was not affected. The presence of IL probably causes an increase in the separation between the cellulose molecules that result in a higher flexibility and processability of the polymeric membrane. The CA/IL/M(0) combinations exhibit an excellent synergistic effect that enhances the activity and durability of the catalyst for the hydrogenation of cyclohexene. The CA/IL/M(0) polymeric membrane displays higher catalytic activity (up to 7.353 h-1) for the 20 mm of CA/IL/Pt(0) and stability than the nanoparticles dispersed only in the IL.

Biomimetic Synthesis of Gelatin Polypeptide-Assisted Noble-Metal Nanoparticles and Their Interaction Study

Liu, Ying; Liu, Xiaoheng; Wang, Xin
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em 02/09/2010 Português
Relevância na Pesquisa
46.42%
Herein, the generation of gold, silver, and silver–gold (Ag–Au) bimetallic nanoparticles was carried out in collagen (gelatin) solution. It first showed that the major ingredient in gelatin polypeptide, glutamic acid, acted as reducing agent to biomimetically synthesize noble metal nanoparticles at 80°C. The size of nanoparticles can be controlled not only by the mass ratio of gelatin to gold ion but also by pH of gelatin solution. Interaction between noble-metal nanoparticles and polypeptide has been investigated by TEM, UV–visible, fluorescence spectroscopy, and HNMR. This study testified that the degradation of gelatin protein could not alter the morphology of nanoparticles, but it made nanoparticles aggregated clusters array (opposing three-dimensional α-helix folding structure) into isolated nanoparticles stabilized by gelatin residues. This is a promising merit of gelatin to apply in the synthesis of nanoparticles. Therefore, gelatin protein is an excellent template for biomimetic synthesis of noble metal/bimetallic nanoparticle growth to form nanometer-sized device.

Electrocatalytic oxidation of small organic molecules in acid medium: enhancement of activity of noble metal nanoparticles and their alloys by supporting or modifying them with metal oxides

Kulesza, Pawel J.; Pieta, Izabela S.; Rutkowska, Iwona A.; Wadas, Anna; Marks, Diana; Klak, Karolina; Stobinski, Leszek; Cox, James A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.42%
Different approaches to enhancement of electrocatalytic activity of noble metal nanoparticles during oxidation of small organic molecules (namely potential fuels for low-temperature fuel cells such as methanol, ethanol and formic acid) are described. A physical approach to the increase of activity of catalytic nanoparticles (e.g. platinum or palladium) involves nanostructuring to obtain highly dispersed systems of high surface area. Recently, the feasibility of enhancing activity of noble metal systems through the formation of bimetallic (e.g. PtRu, PtSn, and PdAu) or even more complex (e.g. PtRuW, PtRuSn) alloys has been demonstrated. In addition to possible changes in the electronic properties of alloys, specific interactions between metals as well as chemical reactivity of the added components have been postulated. We address and emphasize here the possibility of utilization of noble metal and alloyed nanoparticles supported on robust but reactive high surface area metal oxides (e.g. WO3, MoO3, TiO2, ZrO2, V2O5, and CeO2) in oxidative electrocatalysis. This paper concerns the way in which certain inorganic oxides and oxo species can act effectively as supports for noble metal nanoparticles or their alloys during electrocatalytic oxidation of hydrogen and representative organic fuels. Among important issues are possible changes in the morphology and dispersion...

“Green” Nanotechnologies: Synthesis of Metal Nanoparticles Using Plants

Makarov, V. V.; Love, A. J.; Sinitsyna, O. V.; Makarova, S. S.; Yaminsky, I. V.; Taliansky, M. E.; Kalinina, N. O.
Fonte: A.I. Gordeyev Publicador: A.I. Gordeyev
Tipo: Artigo de Revista Científica
Publicado em //2014 Português
Relevância na Pesquisa
46.38%
While metal nanoparticles are being increasingly used in many sectors of the economy, there is growing interest in the biological and environmental safety of their production. The main methods for nanoparticle production are chemical and physical approaches that are often costly and potentially harmful to the environment. The present review is devoted to the possibility of metal nanoparticle synthesis using plant extracts. This approach has been actively pursued in recent years as an alternative, efficient, inexpensive, and environmentally safe method for producing nanoparticles with specified properties. This review provides a detailed analysis of the various factors affecting the morphology, size, and yield of metal nanoparticles. The main focus is on the role of the natural plant biomolecules involved in the bioreduction of metal salts during the nanoparticle synthesis. Examples of effective use of exogenous biomatrices (peptides, proteins, and viral particles) to obtain nanoparticles in plant extracts are discussed.

Functional Application of Noble Metal Nanoparticles In Situ Synthesized on Ramie Fibers

Tang, Bin; Yao, Ya; Li, Jingliang; Qin, Si; Zhu, Haijin; Kaur, Jasjeet; Chen, Wu; Sun, Lu; Wang, Xungai
Fonte: Springer US Publicador: Springer US
Tipo: Artigo de Revista Científica
Publicado em 17/09/2015 Português
Relevância na Pesquisa
46.42%
Different functions were imparted to ramie fibers through treatment with noble metal nanoparticles including silver and gold nanoparticles. The in situ synthesis of silver and gold nanoparticles was achieved by heating in the presence of ramie fibers in the corresponding solutions of precursors. The unique optical property of synthesized noble metal nanoparticles, i.e., localized surface plasmon resonance, endowed ramie fibers with bright colors. Color strength (K/S) of fibers increased with heating temperature. Silver nanoparticles were obtained in alkaline solution, while acidic condition was conducive to gold nanoparticles. The optical properties of treated ramie fibers were investigated using UV-vis absorption spectroscopy. Scanning electron microscopy (SEM) was employed to observe the morphologies of silver and gold nanoparticles in situ synthesized on fibers. The ramie fibers treated with noble metal nanoparticles showed remarkable catalytic activity for reduction of 4-nitrophenol (4-NP) by sodium borohydride. Moreover, the silver nanoparticle treatment showed significant antibacterial property on ramie fibers.

Core-Shell Assisted Bimetallic Assembly of Pt and Ru Nanoparticles by DNA Hybridization

Lee, Jim Yang; Yang, Jun; Too, Heng-Phon; Chow, Gan-Moog; Gan, Leong M.
Fonte: MIT - Massachusetts Institute of Technology Publicador: MIT - Massachusetts Institute of Technology
Tipo: Artigo de Revista Científica Formato: 19871 bytes; application/pdf
Português
Relevância na Pesquisa
56.55%
We have discovered that the current protocols to assemble Au nanoparticles based on DNA hybridization do not work well with the small metal nanoparticles (e.g. 5 nm Au, 3.6 nm Pt and 3.2 nm Ru particles). Further investigations revealed the presence of strong interaction between the oligonucleotide backbone and the surface of the small metal nanoparticles. The oligonucleotides in this case are recumbent on the particle surface and are therefore not optimally oriented for hybridization. The nonspecific adsorption of oligonucleotides on small metal nanoparticles must be overcome before DNA hybridization can be accepted as a general assembly method. Two methods have been suggested as possible solutions to this problem. One is based on the use of stabilizer molecules which compete with the oligonucleotides for adsorption on the metal nanoparticle surface. Unfortunately, the reported success of this approach in small Au nanoparticles (using K₂BSPP) and Au films (using 6-mercapto-1-hexanol) could not be extended to the assembly of Pt and Ru nanoparticles by DNA hybridization. The second approach is to simply use larger metal particles. Indeed most reports on the DNA hybridization induced assembly of Au nanoparticles have made use of relatively large particles (>10 nm)...

Anomalous solubility behavior of mixed monolayer protected metal nanoparticles

Myerson, Jacob W
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 32 leaves; 1399518 bytes; 1398494 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
46.43%
The solubility of mixed monolayer protected gold nanoparticles was studied. Monolayer protected metal nanoparticles are attractive materials because of the optical and electronic properties of their metal cores and because of the surface properties of their ligand coating. Recently, it was discovered that a mixture of ligands phase separate into ordered domains of single nanometer or subnanometer width on the surface of metal nanoparticles. The morphology and length of the ligand domains (which take the form of ripples on the particle surface) has given these nanoparticles novel properties. Because monolayer protected nanoparticles can be dissolved and dried many times, they can be handled and processed in ways not available to other nanomaterials. Understanding the solubility of mixed monolayer protected metal nanoparticles could help in implementing their unique new properties. This study demonstrates that the solubility of these particles in organic solvents cannot be explained only in terms of the composition of the ligand shell. Instead, solubility is also closely linked to morphology of the ligand shell via relationships between the size of the solvent molecule and the size of the features in the morphology.; by Jacob W. Myerson.; Thesis (S.B.)--Massachusetts Institute of Technology...

Metal Nanoparticles/Ionic Liquid/Cellulose: Polymeric Membrane for Hydrogenation Reactions

Gelesky, Marcos Alexandre; Scheeren, Carla Weber
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.24%
Rhodium and platinum nanoparticles were supported in polymeric membranes with 10, 20 and 40 μm thickness. The polymeric membranes were prepared combining cellulose acetate and the ionic liquid (IL) 1-n-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide (BMI.(NTf)2. The presence of metal nanoparticles induced an increase in the polymeric membrane surface areas. The increase of the IL content resulted in an improvement of elasticity and decrease in tenacity and toughness, whereas the stress at break was not affected. The presence of IL probably causes an increase in the separation between the cellulose molecules that result in a higher flexibility and processability of the polymeric membrane. The CA/IL/M(0) combinations exhibit an excellent synergistic effect that enhances the activity and durability of the catalyst for the hydrogenation of cyclohexene. The CA/IL/M(0) polymeric membrane displays higher catalytic activity (up to 7.353 h–1) for the 20 mm of CA/IL/Pt(0) and stability than the nanoparticles dispersed only in the IL.

One-pot fabrication of noble-metal nanoparticles that are encapsulated in hollow silica nanospheres: dual roles of poly(acrylic acid)

Du, X.; Yao, L.; He, J.
Fonte: Wiley Publicador: Wiley
Tipo: Artigo de Revista Científica
Publicado em //2012 Português
Relevância na Pesquisa
56.15%
An efficient and facile one-pot method was developed to fabricate noble-metal nanoparticles (NMNs; Au, Pt, PdO and Ag) that were encapsulated within hollow silica nanospheres (HSNs; NMNs@HSNs) with a size of about 100 nm. NMNs@HSNs were afforded in very high yields between 85–95 %. Poly(acrylic acid) (PAA) polyelectrolyte played a dual role in the fabrication process, both as a core template of the HSNs and as a captor of the NMNs through coordination interactions between the COO− groups on the ammonium polyacrylate (APA) polyanionic chains and the empty orbital of the Au atom. The amount of Au loading in Au@HSNs was easily regulated by varying the volume of the HAuCl4 solution added. In addition, these rattle-type particles were successfully applied in the catalytic reduction of 2-nitroaniline (2-NA) as a model reaction, thus indicating that the micropores in the silica shell could achieve the transport of small species—with a size smaller than that of the micropores—into the cavity. Thus, these fabricated NMNs@HSNs have promising applications in catalysis.; Xin Du, Lin Yao, and Junhui He

Síntese de nanopartículas metálicas suportadas em sílicas mesoporosas organofuncionalizadas; Synthesis of metal nanoparticles supported in organofunctionalized mesoporous silica

Natália Fattori
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 11/11/2014 Português
Relevância na Pesquisa
56.44%
O presente trabalho descreve um método de preparação de nanopartículas metálicas suportadas em sílicas mesoporosas organofuncionalizadas. Dois diferentes substratos foram explorados: uma sílica mesoporosa constituída de uma estrutura porosa altamente ordenada e uniforme, composta de poros ou canais cilíndricos dispostos paralelamente e empacotados em arranjo hexagonal (SBA-15), e uma sílica mesoporosa caracterizada por uma rede desordenada de poros, de tamanho e forma variados, distribuídos e interconectados aleatoriamente ao longo da estrutura porosa (SMD). As duas matrizes tiveram suas superfícies quimicamente modificadas com dois diferentes agentes funcionalizantes constituídos de cátions orgânicos (R+Cl-) com propriedades de troca-iônica, derivados das moléculas 1-metilimidazol (Imi) e 4,4'-bipiridina (Bipy). Em ambos os casos, as propriedades íontrocadoras dos cátions orgânicos ancorados na superfície das sílicas permitem a retenção de ânions complexos de metais nobres ([AuCl4]-, [PtCl6]2- e [PdCl4]2-) confinados na estrutura porosa. Estas espécies foram convertidas in situ nas nanopartículas metálicas de interesse pela redução dos íons metálicos com agentes redutores adequados. As matrizes modificadas com o grupo funcional Imi foram utilizadas como suportes para a preparação e estabilização de nanopartículas metálicas (Au...

Comportamiento electromagnético de nanopartículas de oro. Efecto del tamaño; Electromagnetic behavior of gold nanoparticles. Size effect

Suárez García, Raúl
Fonte: Universidade de Cantabria Publicador: Universidade de Cantabria
Tipo: Trabalho de Conclusão de Curso
Português
Relevância na Pesquisa
56.3%
RESUMEN: En la actualidad, hay una rama de la nanotecnología que está adquiriendo gran importancia debido a las numerosas aplicaciones que pueden surgir. Esta rama es la nanoplasmónica, que es la rama que estudia la interacción de la radiación electromagnética con las nanopartículas metálicas. Las características de las nanoportículas metálicas, en concreto la posibilidad de excitar resonancias plasmónicas superficiales localizadas, hacen de estas una gran herramienta, con un gran número de aplicaciones en diversos campos, como el de las comunicaciones, energías renovables y el de medicina. El oro, cuyo comportamiento es bien conocido, es capaz de excitar resonancias plasmónicas superficiales localizadas y además es un material biocompatible, hace que sean nanopartículas de este material las que se estén investigando o comenzando a emplear en diversas aplicaciones, como por ejemplo en la espectroscopia Raman de superficie aumentada (SERS), como agente terapéutico, como anticonceptivo, etc…[1-3] Es por eso que en este trabajo, se ha realizado un estudio del comportamiento electromagnético de nanopartículas de oro, y el efecto del tamaño de la partícula en este. Se analiza, para nanopartículas de oro de distintos tamaños...

Novel routes for inter-matrix synthesis and characterization of polymer stabilized metal nanoparticles for molecular recognition devices

Muraviev, Dmitri N.; Macanás, Jorge; Farré Urgell, Marinel.la; Muñoz, María; Alegret, Salvador
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 19968 bytes; application/msword
Português
Relevância na Pesquisa
56.23%
10 pages, 7 figures, 1 table.-- Printed version published Oct 25, 2006.-- Issue title: "Eurosensors XIX - The 19th European Conference on Solid-State Transducers"; This paper reports the results obtained by development of novel approaches for inter-matrix synthesis and characterization of polymer stabilized metal nanoparticle (PSMNP), which can be applied in molecular recognition devices (MRD) such as, sensors and biosensors. The proposed approaches are based on the use of functionalized polymeric membranes as a nanoreactor for both synthesis and characterization of PSMNP. The desired functionalization is achieved by either chemical grafting of functional groups to the polymeric matrix or by using physical immobilization of the metal-selective extractants inside the polymer by using solid-phase-incorporated-reagents (SPHINER) technique. In both cases the functional groups of either extractant or functional polymer are able to chemically fix metal ions or complexes inside the parent polymeric matrix prior to their reduction and formation of PSMNP. The results obtained by the inter-matrix synthesis and characterization of Pt- and Cu-PSMNP in polymeric membranes and on the use of these polymer-metal nanocomposite membranes as sensing elements in modified graphite-epoxy composite electrodes are reported and discussed.; This work was supported by research grant BIO2003-06087 from the Ministry of Science and Technology of Spain...

Decoration of multi-walled carbon nanotubes by metal nanoparticles and metal oxides using chemical evaporation method

Masipa,Pheladi M.; Magadzu,Takalani; Mkhondo,Bridget
Fonte: South African Journal of Chemistry Publicador: South African Journal of Chemistry
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2013 Português
Relevância na Pesquisa
66.31%
The powder patterns of the as-prepared and acid treated MWCNTs are shown by the XRD spectra. The TEM results show the microstructure of the multi-walled carbon nanotubes well decorated with metal nanoparticles (Cu, Fe, Ni) and metal oxides (CuO, Fe2O3 NiO), while the SEM show the surface morphology.