Protein Supported Metallic Nanostructures as Catalysts

1999 ◽  
Vol 581 ◽  
Author(s):  
S. Behrens ◽  
W. Habicht ◽  
N. Boukis ◽  
E. Dinjus ◽  
M. Baum ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Noble Metal ◽  
Metallic Nanoparticles ◽  
Size Range ◽  
Metallic Nanostructures ◽  
Metal Salts ◽  
Metal Particles ◽  
Protein Assemblies ◽  
Hydrogenation Reactions ◽  
Nanometer Size Range

ABSTRACTHighly oriented proteins with characteristic nanometer dimensions are used as a template for the synthesis and support of metallic nanoparticles. Following a bottom-up approach, noble metal particles in the nanometer size range were obtained by the reduction of the corresponding metal salts in the presence of the protein assemblies. The catalytic activity of the protein-supported particles was determined by hydrogenation reactions.

One-step synthesis of noble metal/oxide nanocomposites with tunable size of noble metal particles and their size-dependent catalytic activity

RSC Advances ◽  
2014 ◽  
Vol 4 (58) ◽  
pp. 30624-30629 ◽  
Author(s):  
Jie Liu ◽  
Wei Wang ◽  
Tong Shen ◽  
Zhiwei Zhao ◽  
Hui Feng ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Metal Oxide ◽  
Noble Metal ◽  
Metal Particles ◽  
Size Dependent ◽  
One Step

A general one-step synthesis of noble metal/oxide nanocomposites with tunable size of noble metal particles and size-dependent catalytic activity.

Electron Microscopy of the Shape of Small Metal Particles

1977 ◽  
Vol 35 ◽  
pp. 300-301
Author(s):  
M. Jose Yacaman
Keyword(s):  
Electron Microscopy ◽  
Metal Particle ◽  
Field Experiments ◽  
Size Range ◽  
Dark Field ◽  
Metal Particles ◽  
Bragg Condition ◽  
Crystal Particle ◽  
Small Metal Particle ◽  
Small Metal Particles

In the Study of small metal particles the shape is a very Important parameter. Using electron microscopy Ino and Owaga(l) have studied the shape of twinned particles of gold. In that work electron diffraction and contrast (dark field) experiments were used to produce models of a crystal particle. In this work we report a method which can give direct information about the shape of an small metal particle in the amstrong- size range with high resolution. The diffraction pattern of a sample containing small metal particles contains in general several systematic and non- systematic reflections and a two-beam condition can not be used in practice. However a N-beam condition produces a reduced extinction distance. On the other hand if a beam is out of the bragg condition the effective extinction distance is even more reduced.

Analytical Electron Microscopy study of two vehicle-aged automotive exhaust catalysts having dissimilar activities

1989 ◽  
Vol 47 ◽  
pp. 272-273
Author(s):  
Sooho Kim ◽  
M. J. D’Aniello
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Noble Metal ◽  
Catalyst Deactivation ◽  
Analytical Electron Microscopy ◽  
Microscopy Study ◽  
Metal Particles ◽  
Automotive Exhaust ◽  
Exhaust Catalysts ◽  
Analytical Electron

Automotive catalysts generally lose-agtivity during vehicle operation due to several well-known deactivation mechanisms. To gain a more fundamental understanding of catalyst deactivation, the microscopic details of fresh and vehicle-aged commercial pelleted automotive exhaust catalysts containing Pt, Pd and Rh were studied by employing Analytical Electron Microscopy (AEM). Two different vehicle-aged samples containing similar poison levels but having different catalytic activities (denoted better and poorer) were selected for this study.The general microstructure of the supports and the noble metal particles of the two catalysts looks similar; the noble metal particles were generally found to be spherical and often faceted. However, the average noble metal particle size on the poorer catalyst (21 nm) was larger than that on the better catalyst (16 nm). These sizes represent a significant increase over that found on the fresh catalyst (8 nm). The activity of these catalysts decreases as the observed particle size increases.

Biomedical Applications and Patents on Metallic Nanoparticles

2020 ◽  
Vol 10 ◽  
Author(s):  
Geetanjali Singh ◽  
Pramod Kumar Sharma ◽  
Rishabha Malviya
Keyword(s):  
Metallic Nanoparticles ◽  
Biomedical Applications ◽  
Size Range ◽  
Biomedical Application ◽  
Chemical Reduction ◽  
Chemical Methods ◽  
Future Challenges ◽  
Biological Methods ◽  
Cancer Diagnosis And Therapy ◽  
Physical And Chemical

Aim/Objective: The author writes the manuscript by reviewing the literatures related to the biomedical application of metallic nanoparticles. The term metal nanoparticles are used to describe the nanosized metals with the dimension within the size range of 1-100 nm. Methods: The preparation of metallic nanoparticles and their application is an influential area for research. Among various physical and chemical methods (viz. chemical reduction, thermal decomposition, etc.) for synthesizing silver nanoparticles, biological methods have been suggested as possible eco-friendly alternatives. The synthesis of metallic nanoparticles is having many problems inclusive of solvent toxicity, the formation of hazardous byproducts and consumption of energy. So it is important to design eco-friendly benign procedures for the synthesis of metallic nanoparticles. Results: From the literature survey, we concluded that metallic nanoparticles have applications in the treatment of different diseases. Metallic nanoparticles are having a great advantage in the detection of cancer, diagnosis, and therapy. And it can also have properties such as antifungal, antibacterial, anti-inflammatory, antiviral and anti-angiogenic. Conclusion: In this review, recent upcoming advancement of biomedical application of nanotechnology and their future challenges has been discussed.

scholarly journals Immobilization of an Iridium(I)-NHC-Phosphine Catalyst for Hydrogenation Reactions under Batch and Flow Conditions

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 656
Author(s):  
Henrietta Kovács ◽  
Krisztina Orosz ◽  
Gábor Papp ◽  
Ferenc Joó ◽  
Henrietta Horváth
Keyword(s):  
Catalytic Activity ◽  
Ion Exchange ◽  
Heterogeneous Catalyst ◽  
Aqueous Phase ◽  
Levulinic Acid ◽  
Flow Reactor ◽  
High Catalytic Activity ◽  
Flow Conditions ◽  
Hydrogenation Reactions ◽  
Excellent Selectivity

Na2[Ir(cod)(emim)(mtppts)] (1) with high catalytic activity in various organic- and aqueous-phase hydrogenation reactions was immobilized on several types of commercially available ion-exchange supports. The resulting heterogeneous catalyst was investigated in batch reactions and in an H-Cube flow reactor in the hydrogenation of phenylacetylene, diphenylacetylene, 1-hexyne, and benzylideneacetone. Under proper conditions, the catalyst was highly selective in the hydrogenation of alkynes to alkenes, and demonstrated excellent selectivity in C=C over C=O hydrogenation; furthermore, it displayed remarkable stability. Activity of 1 in hydrogenation of levulinic acid to γ-valerolactone was also assessed.

Various Applications of Silver Nano-Particles by Ultrasonic Eco-Fabrication

2005 ◽  
Vol 486-487 ◽  
pp. 530-533 ◽  
Author(s):  
Yamato Hayashi ◽  
Hirotsugu Takizawa ◽  
Yoshitaka Saijo ◽  
Tohru Sekino ◽  
Katsuaki Suganuma ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Noble Metal ◽  
Room Temperature ◽  
Silver Oxide ◽  
Nano Particles ◽  
Metal Particles ◽  
Noble Metal Oxides ◽  
Alcohol System ◽  
Silver Metal ◽  
Suitable Process

Applications of silver nano-sized metal particles were investigated for a new, ecologically friendly and economical liquid-solid (silver oxide-alcohol) system. Silver metal oxides as starting materials have merits in metal particles fabrication because these materials are decomposed only by heating in air. That is, noble metal oxide does not use thestrong reduction atmosphere. This reduction is ecologically clean because many noble metal oxides are not toxic, and because O2 is evolved during decomposition. We reduced silver metal oxides by ultrasound and fabricated silver nano metal nanoparticles at room temperature, and various applications were investigated. By choosing a suitable process and conditions, it is reasonable to expect that ultrasonic eco-fabrications can be extended to obtain various silver nano-particles containing materials.

Nanocomposites: Retrospecr and Prospect

1992 ◽  
Vol 286 ◽  
Author(s):  
Rustum Roy
Keyword(s):  
Major Part ◽  
Size Range ◽  
Nanocomposite Materials ◽  
One Dimension ◽  
New Materials ◽  
Infinite Class ◽  
Materials Synthesis ◽  
The World ◽  
Two Phases ◽  
Nanometer Size Range

ABSTRACTIn this paper we make clear distinctions from the terms nanophase, nanocrystalline and deal only with nanocomposites defined as an interacting mixture of two phases, one of which is in the nanometer size range in at least one dimension. The author's origins of development of the idea that nanocomposites are a virtually infinite class of new materials are described.Then we refer to the results of our extensive studies of nanocomposites derived by solution-solgel techniques to illustrate the properties of such materials in the area of chemical and thermal reactivity.Finally it is pointed out that in the last few years nanocomposite materials have become a major part of new materials synthesis all over the world for applications ranging from mechanical to optical, to magnetic to dielectric.

Asymmetric hydrogenation in nanoreactors with encapsulated Rh-MonoPhos catalyst

2015 ◽  
Vol 17 (3) ◽  
pp. 1702-1709 ◽  
Author(s):  
Mingmei Zhong ◽  
Xiaoming Zhang ◽  
Yaopeng Zhao ◽  
Can Li ◽  
Qihua Yang
Keyword(s):  
Catalytic Activity ◽  
Asymmetric Hydrogenation ◽  
Hydrogenation Reactions ◽  
Multicomponent Catalyst

Encapsulated multicomponent catalyst, Rh-MonoPhos, in nanoreactors showed excellent catalytic activity in the asymmetric hydrogenation reactions.

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