scholarly journals Noble Metal Composite Porous Silk Fibroin Aerogel Fibers

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 894 ◽  
Author(s):  
Alexander Mitropoulos ◽  
F. Burpo ◽  
Chi Nguyen ◽  
Enoch Nagelli ◽  
Madeline Ryu ◽  
...  
Keyword(s):  
Noble Metal ◽  
Silk Fibroin ◽  
Noble Metals ◽  
Metal Salt ◽  
Supercritical Drying ◽  
Noble Metal Nanoparticles ◽  
Metal Composite ◽  
Composite Aerogel ◽  
Wide Range ◽  
Composite Aerogels

Nobel metal composite aerogel fibers made from flexible and porous biopolymers offer a wide range of applications, such as in catalysis and sensing, by functionalizing the nanostructure. However, producing these composite aerogels in a defined shape is challenging for many protein-based biopolymers, especially ones that are not fibrous proteins. Here, we present the synthesis of silk fibroin composite aerogel fibers up to 2 cm in length and a diameter of ~300 μm decorated with noble metal nanoparticles. Lyophilized silk fibroin dissolved in hexafluoro-2-propanol (HFIP) was cast in silicon tubes and physically crosslinked with ethanol to produce porous silk gels. Composite silk aerogel fibers with noble metals were created by equilibrating the gels in noble metal salt solutions reduced with sodium borohydride, followed by supercritical drying. These porous aerogel fibers provide a platform for incorporating noble metals into silk fibroin materials, while also providing a new method to produce porous silk fibers. Noble metal silk aerogel fibers can be used for biological sensing and energy storage applications.

scholarly journals Current Strategies for Noble Metal Nanoparticle Synthesis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Giyaullah Habibullah ◽  
Jitka Viktorova ◽  
Tomas Ruml
Keyword(s):  
Noble Metal ◽  
Noble Metals ◽  
Drug Carriers ◽  
Industrial Applications ◽  
Metal Nanoparticle ◽  
Noble Metal Nanoparticles ◽  
Synthesis Methods ◽  
Gold And Silver Nanoparticles ◽  
Diverse Range ◽  
The Past

AbstractNoble metals have played an integral part in human history for centuries; however, their integration with recent advances in nanotechnology and material sciences have provided new research opportunities in both academia and industry, which has resulted in a new array of advanced applications, including medical ones. Noble metal nanoparticles (NMNPs) have been of great importance in the field of biomedicine over the past few decades due to their importance in personalized healthcare and diagnostics. In particular, platinum, gold and silver nanoparticles have achieved the most dominant spot in the list, thanks to a very diverse range of industrial applications, including biomedical ones such as antimicrobial and antiviral agents, diagnostics, drug carriers and imaging probes. In particular, their superior resistance to extreme conditions of corrosion and oxidation is highly appreciated. Notably, in the past two decades there has been a tremendous advancement in the development of new strategies of more cost-effective and robust NMNP synthesis methods that provide materials with highly tunable physicochemical, optical and thermal properties, and biochemical functionalities. As a result, new advanced hybrid NMNPs with polymer, graphene, carbon nanotubes, quantum dots and core–shell systems have been developed with even more enhanced physicochemical characteristics that has led to exceptional diagnostic and therapeutic applications. In this review, we aim to summarize current advances in the synthesis of NMNPs (Au, Ag and Pt).

scholarly journals Comparative biological effects of spherical noble metal nanoparticles (Rh, Pd, Ag, Pt, Au) with 4–8 nm diameter

2018 ◽  
Vol 9 ◽  
pp. 2763-2774 ◽  
Author(s):  
Alexander Rostek ◽  
Marina Breisch ◽  
Kevin Pappert ◽  
Kateryna Loza ◽  
Marc Heggen ◽  
...  
Keyword(s):  
Metal Nanoparticles ◽  
Noble Metal ◽  
Noble Metals ◽  
Biological Effects ◽  
Human Mesenchymal Stem Cells ◽  
Average Diameter ◽  
Vinyl Pyrrolidone ◽  
Noble Metal Nanoparticles ◽  
Spherical Average ◽  
Size And Morphology

For a comparative cytotoxicity study, nanoparticles of the noble metals Rh, Pd, Ag, Pt, and Au (spherical, average diameter 4 to 8 nm) were prepared by reduction in water and colloidally stabilized with poly(N-vinyl pyrrolidone) (PVP). Thus, their shape, size, and surface functionalization were all the same. Size and morphology of the nanoparticles were determined by dynamic light scattering (DLS), analytical disc centrifugation (differential centrifugal sedimentation, DCS), and high-resolution transmission electron microscopy (HRTEM). Cell-biological experiments were performed to determine the effect of particle exposure on the viability of human mesenchymal stem cells (hMSCs). Except for silver, no adverse effect of any of the metal nanoparticles was observed for concentrations up to 50 ppm (50 mg L−1) incubated for 24 h, indicating that noble metal nanoparticles (rhodium, palladium, platinum, gold) that do not release ions are not cytotoxic under these conditions.

Control of S.I. Engine Exhaust Emissions Using Non-Precious Catalyst (ZSM-5) Supported Bimetals and Noble Metals as Catalyst

2005 ◽  
Author(s):  
Bankim B. Ghosh ◽  
Prokash Chandra Roy ◽  
Mita Ghosh ◽  
Paritosh Bhattacharya ◽  
Rajsekhar Panua ◽  
...  
Keyword(s):  
Noble Metal ◽  
Noble Metals ◽  
Bimetallic Catalyst ◽  
Catalytic Converter ◽  
Exhaust Emissions ◽  
Metal Catalysts ◽  
Oxides Of Nitrogen ◽  
Noble Metal Catalysts ◽  
Maximum Reduction ◽  
Wide Range

Three Way Catalysts (TWC) are extensively used for simultaneous control of three principal automotive pollutants, namely carbon monoxide (CO), Oxides of nitrogen (NOx), and hydrocarbon (HC). Most of works on three way catalytic converter have been carried out with noble metals such as Platinum, Rhodium, and Iridium have been tried individually and in different combinations and proportions. Noble metal catalysts give very good performance of reduction of (NOx), CO and HC in the narrow range of stoichiometric Air Fuel ratio. Noble metals are costly and not abundantly available. These draw backs of the noble metal catalysts have inspired to search for the alternative catalysts, which will perform well over the wide range of A/F ratio and are economical and abundantly available. This paper discusses the processing of ZSM-5 to Cu-Ion- Exchanged ZSM-5, ZSM-5 supported Cu-Pt bimetallic catalyst and Cu-Rh bimetallic catalyst and placing them in a three staged converter to study the reduction efficiencies of exhaust emissions CO, NOx, and HC in a 800 cc Maruti S. I. Engine. The experiments are carried out at 1500 rpm, 17.6 A/F ratio, different catalyst bed temperatures and different engine loads 0%, 17.5%, 35%, 52.5%, and 70% of full load. The results achieved are the maximum reduction of CO 90% at 375 °C NOx 90% at 375 °C and HC 61% at 380 °C. The same engine was also run for Noble metal converter (NMC) (EURO-II) purchased from an authorized Maruti distributor and the maximum reduction achieved were CO 89% at 375° C, NOx 91% at 375° C, and HC 70% at 390° C comparable to Zeolite Catalytic Converter (ZCC).

scholarly journals Noble Metal Nanoparticles-Based Colorimetric Biosensor for Visual Quantification: A Mini Review

Chemosensors ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 53 ◽  
Author(s):  
Lu Yu ◽  
Na Li
Keyword(s):  
Metal Nanoparticles ◽  
Noble Metal ◽  
Electrostatic Interactions ◽  
Organic Molecules ◽  
Chemical Reduction ◽  
Noble Metal Nanoparticles ◽  
Gold And Silver Nanoparticles ◽  
Local Surface Plasmon Resonance ◽  
Reliable Technique ◽  
Wide Range

Nobel metal can be used to form a category of nanoparticles, termed noble metal nanoparticles (NMNPs), which are inert (resistant to oxidation/corrosion) and have unique physical and optical properties. NMNPs, particularly gold and silver nanoparticles (AuNPs and AgNPs), are highly accurate and sensitive visual biosensors for the analytical detection of a wide range of inorganic and organic compounds. The interaction between noble metal nanoparticles (NMNPs) and inorganic/organic molecules produces colorimetric shifts that enable the accurate and sensitive detection of toxins, heavy metal ions, nucleic acids, lipids, proteins, antibodies, and other molecules. Hydrogen bonding, electrostatic interactions, and steric effects of inorganic/organic molecules with NMNPs surface can react or displacing capping agents, inducing crosslinking and non-crosslinking, broadening, or shifting local surface plasmon resonance absorption. NMNPs-based biosensors have been widely applied to a series of simple, rapid, and low-cost diagnostic products using colorimetric readout or simple visual assessment. In this mini review, we introduce the concepts and properties of NMNPs with chemical reduction synthesis, tunable optical property, and surface modification technique that benefit the development of NMNPs-based colorimetric biosensors, especially for the visual quantification. The “aggregation strategy” based detection principle of NMNPs colorimetric biosensors with the mechanism of crosslinking and non-crosslinking have been discussed, particularly, the critical coagulation concentration-based salt titration methodology have been exhibited by derived equations to explain non-crosslinking strategy be applied to NMNPs based visual quantification. Among the broad categories of NMNPs based biosensor detection analyses, we typically focused on four types of molecules (melamine, single/double strand DNA, mercury ions, and proteins) with discussion from the standpoint of the interaction between NMNPs surface with molecules, and DNA engineered NMNPs-based biosensor applications. Taken together, NMNPs-based colorimetric biosensors have the potential to serve as a simple yet reliable technique to enable visual quantification.

scholarly journals Plasmon Assisted Highly Efficient Visible Light Catalytic CO2 Reduction Over the Noble Metal Decorated Sr-Incorporated g-C3N4

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Muhammad Humayun ◽  
Habib Ullah ◽  
Lang Shu ◽  
Xiang Ao ◽  
Asif Ali Tahir ◽  
...  
Keyword(s):  
Visible Light ◽  
Noble Metal ◽  
Light Absorption ◽  
Density Functional ◽  
Noble Metals ◽  
Resonance Effect ◽  
Noble Metal Nanoparticles ◽  
Localized Surface Plasmon ◽  
High Quantum Efficiency ◽  
Conversion Performance

AbstractThe photocatalytic performance of g-C3N4 for CO2 conversion is still inadequate by several shortfalls including the instability, insufficient solar light absorption and rapid charge carrier’s recombination rate. To solve these problems, herein, noble metals (Pt and Au) decorated Sr-incorporated g-C3N4 photocatalysts are fabricated via the simple calcination and photo-deposition methods. The Sr-incorporation remarkably reduced the g-C3N4 band gap from 2.7 to 2.54 eV, as evidenced by the UV–visible absorption spectra and the density functional theory results. The CO2 conversion performance of the catalysts was evaluated under visible light irradiation. The Pt/0.15Sr-CN sample produced 48.55 and 74.54 µmol h−1 g−1 of CH4 and CO, respectively. These amounts are far greater than that produced by the Au/0.15Sr-CN, 0.15Sr-CN, and CN samples. A high quantum efficiency of 2.92% is predicted for the Pt/0.15Sr-CN sample. Further, the stability of the photocatalyst is confirmed via the photocatalytic recyclable test. The improved CO2 conversion performance of the catalyst is accredited to the promoted light absorption and remarkably enhanced charge separation via the Sr-incorporated mid gap states and the localized surface plasmon resonance effect induced by noble metal nanoparticles. This work will provide a new approach for promoting the catalytic efficiency of g-C3N4 for efficient solar fuel production.

scholarly journals Boehmite Nanofiber–Polymethylsilsesquioxane Composite Aerogels: Synthesis, Analysis, and Thermal Conductivity Control via Compression Processing

2020 ◽  
Author(s):  
Gen Hayase
Keyword(s):  
Thermal Conductivity ◽  
Uniaxial Compression ◽  
Catalyst Support ◽  
Aqueous Dispersion ◽  
Supercritical Drying ◽  
Insulation Material ◽  
Composite Aerogel ◽  
Material Development ◽  
Structural Density ◽  
Composite Aerogels

Boehmite nanomaterials have been researched for use in applications such as separation media, fillers for resins, and catalyst support. This study investigates the relationship between structural density and mechanical and thermal performance of boehmite nanofiber-polymethylsilsesquioxane composite aerogels. Tri-functional organosilicon alkoxide, methyltrimethoxysilane (MTMS), was added to a boehmite nanofibers aqueous dispersion, the colloidal nanofibers were coated and bonded with polymethylsilsesquioxane (PMSQ), to produce transparent to translucent wet gel monoliths. Low bulk density composite aerogel panels were prepared by CO2 supercritical drying of the wet gel monoliths before their mechanical properties and thermal conductivity were investigated. As the amount of the MTMS in the starting composition increased, the fibrillar monolith skeleton coated with PMSQ thickened. Correspondingly, the Young's modulus of the monoliths increased, and the thermal conductivity decreased. When the amount of MTMS added was small, it was possible to deform the translucent panels by uniaxial compression. After 30 % uniaxial compression of the panel, the thermal conductivity was suppressed by 19 %. The thermal conductivity response to compressive deformation of fibrous aerogels, after fabrication, may inform future insulation material development.

A universal approach to the synthesis of nanodendrites of noble metals

Nanoscale ◽  
2014 ◽  
Vol 6 (11) ◽  
pp. 6173-6179 ◽  
Author(s):  
Yan Feng ◽  
Xiaohong Ma ◽  
Lin Han ◽  
Zhijian Peng ◽  
Jun Yang
Keyword(s):  
Metal Nanoparticles ◽  
Noble Metal ◽  
Noble Metals ◽  
Noble Metal Nanoparticles ◽  
Universal Approach ◽  
Dendritic Structures

A universal approach was demonstrated for the synthesis of noble metal nanoparticles with dendritic structures.

Electrochemical Sensors Based on Noble Metal Nanoparticles in Voltammetry

2021 ◽  
Vol 887 ◽  
pp. 54-59
Author(s):  
D.O. Perevezentseva ◽  
Eduard V. Gorchakov
Keyword(s):  
Metal Nanoparticles ◽  
Noble Metal ◽  
Electrochemical Sensors ◽  
Narrow Range ◽  
Spherical Shape ◽  
High Sensitivity ◽  
Noble Metal Nanoparticles ◽  
Wide Range ◽  
Sulfur Containing

Portable electrochemical sensors based on noble metal nanoparticles (МеNPs) for the quantitative determination of hydrogen peroxide (H2O2) and sulfur-containing amino acids (cysteine, methionine, glutathione) are discussed. These sensors have high sensitivity (pM), with low sample requirements (<50 μl). This article discusses methods for producing sensors based on silver and gold nanoparticles and their application in voltammetry. It is shown that the sensitivity of H2O2 determination on a sensor based on silver nanoparticles (AgNPs) depends on their size. Their size is determined by the reducing agent. Sensors based on AgNPs of spherical shape with the smallest size from 0.5 to 17.5 nm have the highest sensitivity for determining H2O2, but a narrow range of determined concentrations. Sensors on medium-sized AgNPs have optimal metrological characteristics. Their size is from 10 to 55 nm, less sensitive, but with a wide range of determined concentrations from 0.1 to 1 nm H2O2. The linearity of the range of glutathione concentrations is 1.0-10.0 pM. The linearity of the range of determined concentrations of methionine is 1–26 рМ.

The in vitro effect of commercially available noble metal nanocolloids on the splenocyte proliferative response and cytokine production in mice

2014 ◽  
Vol 17 (1) ◽  
pp. 37-45 ◽  
Author(s):  
J. Małaczewska
Keyword(s):  
Noble Metal ◽  
Proliferative Activity ◽  
Noble Metals ◽  
Living Organism ◽  
Reticuloendothelial System ◽  
Noble Metal Nanoparticles ◽  
Mouse Splenocytes ◽  
Toxic Concentrations ◽  
Vitro Effect

Abstract Noble metal nanoparticles, currently among the most popular types of nanomaterials, are capable of penetrating through biological barriers once they enter a living organism. There, they can permeate into organs possessing the reticuloendothelial system, such as the spleen. The objective of this study was to determine the effect of commercial nanocolloids of noble metals (silver, gold and copper), recommended by the manufacturer as dietary supplements, on the in vitro viability, proliferative activity and production of cytokines (IL-1β, IL-2, IL-6, IL- 10 and TNF-α) by mouse splenocytes. All of the analyzed colloids had some effect on the activity of mouse splenocytes. Silver colloid was characterized by high toxicity - concentrations of 1.25 ppm and above substantially depressed the viability of cells as well as their proliferative activity and ability to synthesize cytokines. The other two colloids were far less toxic than nanosilver, although their non-toxic concentrations had a significant effect on the production of cytokines by mitogen activated splenocytes. The colloid of gold decreased the level of IL-2, and the colloid of copper caused an increase in IL-2, IL6 and Il-10. At the same time, copper colloid alone induced the synthesis of IL-1β in mitogen unstimulated cells. The results indicate that colloids of noble metals are capable of affecting the activity of immunocompetent cells in important peripheral organs of the immune system.

scholarly journals Synthesis and characterization of fluorescence-labelled silica core-shell and noble metal-decorated ceria nanoparticles

2014 ◽  
Vol 5 ◽  
pp. 2413-2423 ◽  
Author(s):  
Rudolf Herrmann ◽  
Markus Rennhak ◽  
Armin Reller
Keyword(s):  
Noble Metal ◽  
Noble Metals ◽  
Synthetic Methods ◽  
Noble Metal Nanoparticles ◽  
Synthesis And Characterization ◽  
Core Shell ◽  
Ceria Nanoparticles ◽  
Thiol Groups ◽  
Silica Core

The present review article covers work done in the cluster NPBIOMEM in the DFG priority programme SPP 1313 and focuses on synthesis and characterization of fluorescent silica and ceria nanoparticles. Synthetic methods for labelling of silica and polyorganosiloxane/silica core–shell nanoparticles with perylenediimide derivatives are described, as well as the modification of the shell with thiol groups. Photometric methods for the determination of the number of thiol groups and an estimate for the number of fluorescent molecules per nanoparticles, including a scattering correction, have been developed. Ceria nanoparticles decorated with noble metals (Pt, Pd, Rh) are models for the decomposition products of automobile catalytic converters which appear in the exhaust gases and finally interact with biological systems including humans. The control of the degree of agglomeration of small ceria nanoparticles is the basis for their synthesis. Almost monodisperse agglomerates (40 ± 4–260 ± 40 nm diameter) can be prepared and decorated with noble metal nanoparticles (2–5 nm diameter). Fluorescence labelling with ATTO 647N gave the model particles which are now under biophysical investigation.

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