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Carbon nanotubes

Asiful Alam, Simone Dehm, Frank Hennrich, Yuriy Zakharko, Arko Graf, Moritz Pfohl, Ihteaz M Hossain, Manfred M Kappes, Jana Zaumseil, Ralph Krupke, Benjamin S Flavel
Monochiral (7,5) single walled carbon nanotubes (SWCNTs) are integrated into a field effect transistor device in which the built-in electric field at the nanotube/metal contact allows for exciton separation under illumination. Variable wavelength spectroscopy and 2D surface mapping of devices consisting of 10-20 nanotubes are performed in the visible region and a strong correlation between the nanotube's second optical transition (S22) and the photocurrent is found. After integration, the SWCNTs are non-covalently modified with three different fluorescent dye molecules with off-resonant absorption maxima at 532 nm, 565 nm, and 610 nm...
July 27, 2017: Nanoscale
Bharat Kumar, Abram L Falk, Ali Afzali, George S Tulevski, Satoshi Oida, Shu-Jen Han, James B Hannon
High performance logic based on carbon nanotubes (CNTs) requires high density arrays of selectively placed semiconducting CNTs. Although polymer-wrapping methods can allow CNTs to be sorted to a >99.9% semiconducting purity, patterning these polymer-wrapped CNTs is an outstanding problem. We report the directed self-assembly of polymer coated semiconducting CNTs using self-assembled monolayers that bind CNTs into arrays of patterned trenches. We demonstrate that CNTs can be placed into 100 nm wide HfO2 trenches with an electrical connection yield as high as 90%, and into 50 nm wide trenches with a yield as high as 70%...
July 27, 2017: ACS Nano
Liye Zhang, Junshan Yin, Wei Yu, Mingzhu Wang, Huaqing Xie
In this paper, ultra-long copper nanowires (CuNWs) were successfully synthesized at a large scale by hydrothermal reduction of divalent copper ion using oleylamine and oleic acid as dual ligands. The characteristic of CuNWs is hard and linear, which is clearly different from graphene nanoplatelets (GNPs) and multi-wall carbon nanotubes (MWCNTs). The thermal properties and models of silicone composites with three nanomaterials have been mainly researched. The maximum of thermal conductivity enhancement is up to 215% with only 1...
December 2017: Nanoscale Research Letters
Ahmed Refaat Bakr, Md Saifur Rahaman
Bisphenol A is a chemical with hazardous health effects that is largely used in the manufacture of extensively used products including adhesives, plastics, powder paints, thermal paper and paper coatings, and epoxy resin, and is reported to exist in nature in an accumulative manner. In this study, both pristine and boron-doped multiwalled carbon nanotubes (MWNTs) were employed as filtration and electrochemical filtration materials, resulting in a significant removal of bisphenol A with identical performance for both MWNTs types...
July 17, 2017: Chemosphere
Santosh Phuyal, Mayes Kasem, Laura Rubio, Hanna L Karlsson, Ricard Marcos, Vidar Skaug, Shanbeh Zienolddiny
The most plausible exposure route to manufactured nanomaterials (MNM) remains pulmonary inhalation. Yet, few studies have attempted to assess carcinogenic properties in vitro following long-term exposure of human pulmonary cells to low and occupationally relevant doses. The most advanced in vitro tests for carcinogenicity, the cell transformation assay (CTA), relying mostly on rodent cells and short-term exposure. We hypothesized that long-term exposure of human bronchial epithelial cells with a normal phenotype could be a valuable assay for testing carcinogenicity of nanomaterials...
July 23, 2017: Toxicology in Vitro: An International Journal Published in Association with BIBRA
Alex Chortos, Chenxin Zhu, Jin Young Oh, Xuzhou Yan, Igor Pochorovski, John W F To, Nan Liu, Ulrike Kraft, Boris Murmann, Zhenan Bao
Stretchable form factors enable electronic devices to conform to irregular 3D structures, including soft and moving entities. Intrinsically stretchable devices have potential advantages of high surface coverage of active devices, improved durability, and reduced processing costs. This work describes intrinsically stretchable transistors composed of single walled carbon nanotube (SWNT) electrodes and semiconductors and a dielectric that consists of a nonpolar elastomer. The use of a non-polar elastomer dielectric enabled hysteresis-free device characteristics...
July 26, 2017: ACS Nano
Ricardo Venegas, Francisco J Recio, Cesar Zuñiga, Marco Viera, María-Paz Oyarzún, Nataly Silva, Karinna Neira, José F Marco, José H Zagal, Federico Tasca
We have compared the electrocatalytic activity of several substituted and unsubstituted Co and Fe N4-macrocyclic complexes (MN4) for the electro-reduction of oxygen with the complexes directly adsorbed on the edge plane of pyrolytic graphite or adsorbed on carbon nanotubes (CNTs). In the presence of CNTs, one order of magnitude higher surface concentrations of MN4 catalysts per geometric area unit could be adsorbed leading to a lower overpotential for the oxygen electro-reduction and activities in the same order of magnitude as the commercially available Pt/C catalysts in basic pH...
July 26, 2017: Physical Chemistry Chemical Physics: PCCP
Zhanwei Xu, Xiaoli Fan, Hejun Li, Hao Fu, Woon Ming Lau, Xueni Zhao
We invented a practical and simple wet-grinding method to break conventional graphene sheets and CNTs for the production of new graphene/CNTs with adequate edge density (about 25 000 atoms per graphene-fragment of about 1 μm(2) in size) and no detectable changes in intrinsic defects, extrinsic impurities, and even surface-area. Measurements using the standard cyclic voltammetry, rotating disk electrode and rotating ring-disk electrode techniques all confirm that such mildly fragmented graphene, as well as carbon-nanotubes treated similarly using this wet-grinding method, can facilitate the fast 4-electron oxygen reduction reaction (ORR) pathway...
July 26, 2017: Physical Chemistry Chemical Physics: PCCP
Shuoyu Li, Yuyi Liu, Peisheng Guo, Chengxin Wang
A composed material of amorphous carbon nanotubes (ACNTs) and encapsulated transition metal oxide (TMOs) nanoparticles was prepared by a common thermo physics effect which is named Marangoni effect and a simple anneal progress. The prepared ropy solution would form a Marangoni convection and climb into the channel of anodic aluminum oxide template (AAO) spontaneously. The ingenious design of the preparation method determined a distinctive structure which TMOs nanoparticles with size of ~5nm and amorphous carbon coated outside full in the ACNTs...
July 26, 2017: ACS Applied Materials & Interfaces
Antonio Setaro
Similarly to graphene, carbon nanotubes are materials made of pure carbon in its sp2 form. Their extended conjugated π-network provides them with amazing quantum optoelectronic properties. Frustratingly, it also brings drawbacks: The π-π stacking interaction makes as-produced tubes bundle together, blurring out all their quantum properties. Functionalization aims at modifying and protecting the tubes while hindering π-π stacking. Several functionalization strategies have been developed to circumvent this limitation and for nanotubes applications to thrive...
July 26, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Jing Bai, Zixing Shi
Pristine carbon nanotubes (CNTs) were activated to exhibit Diels-Alder (DA) reactivity in a polymer matrix, which was modified with monomers containing furan groups. The DA-active polymer matrix was transferred into a dynamic reversible crosslinked inorganic-organic network via a Diels-Alder reaction with CNTs, where pristine CNTs were used as dienophile chemicals and furan-modified SBS acted as the macromolecular diene. In this system, the mechanical properties as well as resilience and solvent resistance were greatly improved even with the presence of only 1 wt% CNTs...
July 26, 2017: ACS Applied Materials & Interfaces
Meshal Alzaid, Joseph Roth, Yuezhou Wang, Eid Almutairi, Samuel L Brown, Traian Dumitrica, Erik K Hobbie
Thin bilayers of contrasting nanomaterials are ubiquitous in solution-processed electronic devices and have potential relevance to a number of applications in flexible electronics. Motivated by recent mesoscopic simulations demonstrating synergistic mechanical interactions between thin films of single-wall carbon nanotubes (SWCNTs) and spherical nanocrystal (NC) inclusions, we use a thin-film wrinkling approach to query the compressive mechanics of hybrid nanotube/nanocrystal coatings adhered to soft polymer substrates...
July 25, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Jie Chen, Rujuta Munje, Nicholas P Godman, Shalini Prasad, Daniel T Glatzhofer, David W Schmidtke
The effect of incorporating different types of carbon nanotubes into composite films of a redox polymer (FcMe2-C3-LPEI) and glucose oxidase (GOX) was investigated. The composite films were constructed by first forming a high-surface area network film of either single-walled carbon nanotubes (SWNTs) or multiwalled carbon nanotubes (MWNTs) on a glassy carbon electrode (GCE) by solution casting of a suspension of Triton-X-100 dispersed SWNTs. Next a glucose responsive redox hydrogel was formed on top of the nanotube-modified electrode by cross-linking FcMe2-C3-LPEI with glucose oxidase via ethylene glycol diglycidyl ether (EGDGE)...
July 25, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Kourtney Wright, Cathren E Gowenlock, Joseph Charles Bear, Andrew R Barron
We present a study of the seeded growth of copper on the surface of two classes of single-walled carbon nanotubes (SWNTs) in order to compare the effects of surface functional groups. Pyridine functionalized HiPco SWNTs and ultra-short SWNTs (US-SWNTs) were synthesized (py-SWNTs and py-US-SWNTs, respectively) and the functionality used as seed sites for copper, via an aqueous electroless deposition reaction, as a comparison to carboxylic acid functionality present on piranha etched SWNTs and the native US-SWNTs...
July 25, 2017: ACS Applied Materials & Interfaces
Juhan Lee, Pattarachai Srimuk, Katherine Aristizabal, Choonsoo Kim, Soumyadip Choudhury, Yoon-Chae Nah, Frank Mücklich, Volker Presser
We introduce membrane pseudocapacitive deionization (MPDI) of a hybrid cell consisting of one electrode of hydrated vanadium pentoxide (hV2O5) decorated on multi-walled carbon nanotubes electrode (MWCNT) and one electrode of activated carbon. This hybrid system enables sodium removal by pseudocapacitive intercalation to MWCNT-hV2O5 electrode and chloride removal by non-Faradaic electrosorption of the porous carbon electrode. MWCNT-hV2O5 electrode was synthesized by electrochemical deposition of hydrated vanadium pentoxide on the MWCNT paper...
July 25, 2017: ChemSusChem
Meng-Qiang Zhao, Xiuqiang Xie, Chang E Ren, Taron Makaryan, Babak Anasori, Guoxiu Wang, Yury Gogotsi
2D transition metal carbides and nitrides, named MXenes, are attracting increasing attentions and showing competitive performance in energy storage devices including electrochemical capacitors, lithium- and sodium-ion batteries, and lithium-sulfur batteries. However, similar to other 2D materials, MXene nanosheets are inclined to stack together, limiting the device performance. In order to fully utilize MXenes' electrochemical energy storage capability, here, processing of 2D MXene flakes into hollow spheres and 3D architectures via a template method is reported...
July 25, 2017: Advanced Materials
Chuanfang John Zhang, Babak Anasori, Andrés Seral-Ascaso, Sang-Hoon Park, Niall McEvoy, Aleksey Shmeliov, Georg S Duesberg, Jonathan N Coleman, Yury Gogotsi, Valeria Nicolosi
2D transition-metal carbides and nitrides, known as MXenes, have displayed promising properties in numerous applications, such as energy storage, electromagnetic interference shielding, and catalysis. Titanium carbide MXene (Ti3 C2 Tx ), in particular, has shown significant energy-storage capability. However, previously, only micrometer-thick, nontransparent films were studied. Here, highly transparent and conductive Ti3 C2 Tx films and their application as transparent, solid-state supercapacitors are reported...
July 25, 2017: Advanced Materials
Meihua Huang, Jianshuo Zhang, Chuxin Wu, Lunhui Guan
Pt nanoparticles (NPs) coated on SnO2-coverd multi-walled carbon nanotubes (MWCNTs@SnO2@Pt) have been designed to enhance the activity and stability of Pt catalysts. The weight percentage of Pt in the MWCNTs@SnO2@Pt reaches as high as 85%. Thanks for the unique one-dimensional structure, the Pt mass activity of MWCNTs@SnO2@Pt for methanol oxidation is 6.2 times as active as that of the commercial Pt/C. The durability and anti-poisoning ability were also improved greatly. The enhanced intrinsic performance was ascribed to the densely connected networks of Pt NPs on the SnO2 NPs...
July 25, 2017: ACS Applied Materials & Interfaces
P T Saheli, R K Rowe, E J Petersen, D M O'Carroll
The new applications for carbon nanotubes (CNTs) in various fields and consequently their greater production volume have increased their potential release to the environment. Landfills are one of the major locations where carbon nanotubes are expected to be disposed and it is important to ensure that they can limit the release of CNTs. Diffusion of multiwall carbon nanotubes (MWCNTs) dispersed in an aqueous media through a high-density polyethylene (HDPE) geomembrane (as a part of the landfill barrier system) was examined...
May 2017: Geosynth Int
Pin Ann Lin, Jose L Gomez-Ballesteros, Juan C Burgos, Perla B Balbuena, Bharath Natarajan, Renu Sharma
Rational catalyst design requires an atomic scale mechanistic understanding of the chemical pathways involved in the catalytic process. A heterogeneous catalyst typically works by adsorbing reactants onto its surface, where the energies for specific bonds to dissociate and/or combine with other species (to form desired intermediate or final products) are lower. Here, using the catalytic growth of single-walled carbon nanotubes (SWCNTs) as a prototype reaction, we show that the chemical pathway may in-fact involve the entire catalyst particle, and can proceed via the fluctuations in the formation and decomposition of metastable phases in the particle interior...
May 2017: Journal of Catalysis
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