scholarly journals Catalysis with carbon nanoparticles

RSC Advances ◽  
2019 ◽  
Vol 9 (47) ◽  
pp. 27659-27664 ◽  
Author(s):  
Caterina Testa ◽  
Agatino Zammataro ◽  
Andrea Pappalardo ◽  
Giuseppe Trusso Sfrazzetto
Keyword(s):  
Carbon Nanoparticles ◽  
New Class ◽  
Catalytic Applications

Carbon nanoparticles represent a new class of nanocatalysts able to catalyze different reactions. This review collects the catalytic applications of these nanoparticles.

scholarly journals Percolation Conduction of Carbon Nanocomposites

2020 ◽  
Vol 21 (20) ◽  
pp. 7634
Author(s):  
Grigorii S. Bocharov ◽  
Alexander V. Eletskii
Keyword(s):  
Carbon Nanoparticles ◽  
Electron Tunneling ◽  
Model Description ◽  
Electrical Field ◽  
Electrical Field Strength ◽  
Carbon Nanocomposites ◽  
New Class ◽  
Ohmic Behavior ◽  
Calculation Results ◽  
Small Additive

Carbon nanocomposites present a new class of nanomaterials in which conducting carbon nanoparticles are a small additive to a non-conducting matrix. A typical example of such composites is a polymer matrix doped with carbon nanotubes (CNT). Due to a high aspect ratio of CNTs, inserting rather low quantity of nanotubes (on the level of 0.01%) results in the percolation transition, which causes the enhancement in the conductivity of the material by 10–12 orders of magnitude. Another type of nanocarbon composite is a film produced as a result of reduction of graphene oxide (GO). Such a film is consisted of GO fragments whose conductivity is determined by the degree of reduction. A distinctive peculiarity of both types of nanocomposites relates to the dependence of the conductivity of those materials on the applied voltage. Such a behavior is caused by a non-ideal contact between neighboring carbon nanoparticles incorporated into the composite. The resistance of such a contact depends sharply on the electrical field strength and therefore on the distance between neighboring nanoparticles. Experiments demonstrating non-linear, non-Ohmic behavior of both above-mentioned types of carbon nanocomposites are considered in the present article. There has been a model description presented of such a behavior based on the quasi-classical approach to the problem of electron tunneling through the barrier formed by the electric field. The calculation results correspond qualitatively to the available experimental data.

scholarly journals Synthesis and Luminescent Properties of Carbon Nanodots Dispersed in Nanostructured Silicas

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3267
Author(s):  
Andrii Vasin ◽  
Dmytro Kysil ◽  
Andriy Rusavsky ◽  
Oksana Isaieva ◽  
Alexander Zaderko ◽  
...  
Keyword(s):  
Carbon Nanoparticles ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Carbon Nanodots ◽  
Ultraviolet Emission ◽  
Organic Precursor ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
New Class ◽  
Nanostructured Silica

Luminescent carbon nanoparticles are a relatively new class of luminescent materials that have attracted the increasing interest of chemists, physicists, biologists and engineers. The present review has a particular focus on the synthesis and luminescent properties of carbon nanoparticles dispersed inside nanostructured silica of different natures: oxidized porous silicon, amorphous thin films, nanopowders, and nanoporous sol–gel-derived ceramics. The correlations of processing conditions with emission/excitation spectral properties, relaxation kinetics, and photoluminescence photodegradation behaviors are analyzed. Following the evolution of the photoluminescence (PL) through the “from-bottom-to-up” synthesis procedure, the transformation of molecular-like ultraviolet emission of organic precursor into visible emission of carbon nanoparticles is demonstrated. At the end of the review, a novel method for the synthesis of luminescent and transparent composites, in form of nanoporous silica filled with luminescent carbon nanodots, is presented. A prototype of white light emitting devices, constructed on the basis of such luminophores and violet light emitting diodes, is demonstrated.

Phosphorene quantum dots: synthesis, properties and catalytic applications

Nanoscale ◽  
2022 ◽  
Author(s):  
Manila Ozhukil Valappil ◽  
Subbiah Alwarappan ◽  
Vijayamohanan K. Pillai
Keyword(s):  
Quantum Dots ◽  
Surface Properties ◽  
Functional Nanostructures ◽  
New Class ◽  
Synthesis Properties ◽  
Catalytic Applications

Phosphorene quantum dots (PQDs) belong to a new class of zero-dimensional functional nanostructures with unique physicochemical and surface properties in comparison with few-layer phosphorene and other 2D analogues.

Carbon Dots as Catalysts: A New Class of Nanozymes

2019 ◽  
Vol 7 (1) ◽  
pp. 3-6
Author(s):  
Agatino Zammataro ◽  
Giuseppe Trusso Sfrazzetto
Keyword(s):  
Carbon Dots ◽  
Future Perspectives ◽  
New Class ◽  
Catalytic Applications ◽  
Application Fields ◽  
Carbon Based

Carbon Dots (CDs) represent a new class of nanoparticles carbon-based having many application fields. This perspective summarizes the catalytic applications of CDs with potential future perspectives.

In Situ microscopy of the anodic etching of silicon

1995 ◽  
Vol 53 ◽  
pp. 232-233
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Selective Etching ◽  
Silicon On Insulator ◽  
Second Phase ◽  
Porous Layers ◽  
New Class ◽  
Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

The microtubule associated protein (MAP) tau forms a new class of triple-stranded left-hand helical fibrous protein polymer

1992 ◽  
Vol 50 (1) ◽  
pp. 540-541
Author(s):  
G. C. Ruben ◽  
K. Iqbal ◽  
I. Grundke-Iqbal ◽  
H. Wisniewski ◽  
T. L. Ciardelli ◽  
...  
Keyword(s):  
Axial Ratio ◽  
Normal Structure ◽  
Paired Helical Filaments ◽  
Left Hand ◽  
New Class ◽  
Protein Polymer ◽  
Fibrous Protein ◽  
Protein Map ◽  
Neurotransmitter Transport ◽  
Alzheimer Neurofibrillary Tangles

In neurons, the microtubule associated protein, tau, is found in the axons. Tau stabilizes the microtubules required for neurotransmitter transport to the axonal terminal. Since tau has been found in both Alzheimer neurofibrillary tangles (NFT) and in paired helical filaments (PHF), the study of tau's normal structure had to preceed TEM studies of NFT and PHF. The structure of tau was first studied by ultracentrifugation. This work suggested that it was a rod shaped molecule with an axial ratio of 20:1. More recently, paraciystals of phosphorylated and nonphosphoiylated tau have been reported. Phosphorylated tau was 90-95 nm in length and 3-6 nm in diameter where as nonphosphorylated tau was 69-75 nm in length. A shorter length of 30 nm was reported for undamaged tau indicating that it is an extremely flexible molecule. Tau was also studied in relation to microtubules, and its length was found to be 56.1±14.1 nm.

Study of segregation in La1.8Sr0.2CuO4 superconductor by STEM-EDS microanalysis

1987 ◽  
Vol 45 ◽  
pp. 54-55
Author(s):  
T. F. Kelly ◽  
P. J. Lee ◽  
E. E. Hellstrom ◽  
D. C. Larbalestier
Keyword(s):  
Rare Earth ◽  
High Field ◽  
Transport Current ◽  
Total Thickness ◽  
New Class ◽  
Ceramic Superconductors ◽  
Current Densities ◽  
Group Ii ◽  
Eds Microanalysis

Recently there has been much excitement over a new class of high Tc (>30 K) ceramic superconductors of the form A1-xBxCuO4-x, where A is a rare earth and B is from Group II. Unfortunately these materials have only been able to support small transport current densities 1-10 A/cm2. It is very desirable to increase these values by 2 to 3 orders of magnitude for useful high field applications. The reason for these small transport currents is as yet unknown. Evidence has, however, been presented for superconducting clusters on a 50-100 nm scale and on a 1-3 μm scale. We therefore planned a detailed TEM and STEM microanalysis study in order to see whether any evidence for the clusters could be seen.A La1.8Sr0.2Cu04 pellet was cut into 1 mm thick slices from which 3 mm discs were cut. The discs were subsequently mechanically ground to 100 μm total thickness and dimpled to 20 μm thickness at the center.

Electronic structure studies of conducting polymers by electron energy-loss spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 160-161
Author(s):  
J. Fink
Keyword(s):  
Electronic Structure ◽  
Conducting Polymers ◽  
Conjugated Polymers ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Light Emitting ◽  
One Dimensional ◽  
New Class ◽  
Electrical Conductivities ◽  
Electron Energy Loss

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

Mechanochemical changes on cyclometalated Ir(iii) acyclic carbene complexes – design and tuning of luminescent mechanochromic transition metal complexes

2020 ◽  
Vol 7 (3) ◽  
pp. 786-794 ◽  
Author(s):  
Jingqi Han ◽  
Kin-Man Tang ◽  
Shun-Cheung Cheng ◽  
Chi-On Ng ◽  
Yuen-Kiu Chun ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Carbene Complexes ◽  
New Class

A new class of luminescent cyclometalated Ir(iii) complexes with readily tunable mechanochromic properties derived from the mechanically induced trans-to-cis isomerization have been developed.

Amino-functional polyethers: versatile, stimuli-responsive polymers

2020 ◽  
Vol 11 (24) ◽  
pp. 3940-3950 ◽  
Author(s):  
Patrick Verkoyen ◽  
Holger Frey
Keyword(s):  
Ring Opening ◽  
Review Article ◽  
Stimuli Responsive ◽  
New Class ◽  
Stimuli Responsive Polymers ◽  
Responsive Polymers

Amino-functional polyethers have emerged as a new class of “smart”, i.e. pH- and thermoresponsive materials. This review article summarizes the synthesis and applications of these materials, obtained from ring-opening of suitable epoxide monomers.

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