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[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]
Researchers Double Activity of Platinum Catalyst in Methanol Fuel Cells by Using Surface Steps
October 19, 2009
| Left.High-resolution Transmission Electron Microscopy image of platinum nanoparticles on a fuel cell electrode. Right. Schematics of high-index planes observed on Pt nanoparticles. Credit: ACS, Lee at al. (2009). Click to enlarge. |
A team of researchers from MIT, the Japan Institute of Science and Technology, and Brookhaven National Laboratory have found that changing the surface texture of platinum used in a methanol fuel cell electrode—specifically, creating nano surface steps instead of using a smooth surface—can significantly increase the catalytic activity.
In a paper published online 13 October in the Journal of the American Chemical Society, they show a linear relationship between the intrinsic activity and the amounts of surface steps. Increasing surface steps on Pt nanoparticles of ~2 nm led to enhanced intrinsic activity up to 200% (current normalized to Pt surface area) for electro-oxidation of methanol.
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Researchers Propose Single Nanorod Devices for Better Li-ion Battery Diagnostics
October 12, 2009
| SEM images of nanorod devices in 1 M LiPF6 in the EC/DEC electrolyte: LiMn2O4 (a) 0, (b) 3, and (c) 9 h; LiAl0.1Mn1.9O4 (d) 0, (e) 3, and (f) 9 h; λ-MnO2 (g) 0, (h) 3, and (i) 9 h. Credit: ACS, Yang et al. Click to enlarge. |
An international team of researchers from Stanford University, Università degli Studi di Milano-Bicocca, and Korea Advanced Institute of Science and Technology (KAIST) is proposing the use of single nanostructure devices as a powerful new diagnostic tool for Li-ion batteries. A paper on their work was published online 6 October in the ACS journal Nano Letters.
The electrodes in lithium-ion batteries consist of particles with various sizes and shapes, conductive carbon, and polymer binders. During battery charge/discharge, the insertion or extraction of electrons and ions is accompanied by a series of other complex processes such as structure and phase transformation, volume change, materials dissolution, and side chemical reaction with electrolyte, the authors note. While a number of different technologies have been used for battery diagnostics, “the heterogeneous nature of ensemble electrodes averages all information and can not provide a direct correlation of electrochemical properties with the local morphology, structure, and chemical composition.”
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Honda-Led Research Team Devises Method to Control Growth of Nanotubes with Metallic Conductivity
October 01, 2009
| Carbon nanotubes are preferentially grown by controlling the shape and size of the catalyst. Tubes growing on red and pink exhibit metallic properties, while semiconducting tubes are on blue. The height of the nanotubes indicates the probability of each specific tube in the experiment. Source: Honda RI. Click to enlarge. |
A team of researchers from Honda Research Institute USA, Inc., in conjunction with researchers at Purdue University and the University of Louisville, has developed a method for controllably growing carbon nanotubes with metallic conductivity. With further optimization, the researchers say, “direct control over nanotube structure during growth may well be feasible.” A paper on their work appears in the 2 Oct issue of the journal Science.
Carbon nanotubes are grown on the surface of metal nanoparticles, and take the form of rolled graphene sheets. The nanotube bonding configuration is known as its chirality. The chirality determines the conductivity of the nanotube—i.e., either metallic or semiconducting. Nanotubes exhibiting metallic conductivity possess extraordinary strength compared to steel, higher electrical properties than copper, are as efficient in conducting heat as a diamond and are as light as cotton.
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New Graphene Nanomaterial Could Result in More Fuel-Efficient Airplanes and Cars; Applications in Energy Storage
July 31, 2009
| Exfoliated Graphite NanoPlatelets. Bottom: lateral and edge views. Source: MSU, XG Sciences. Click to enlarge. |
A Michigan State University (MSU) researcher and his students have developed a nanomaterial—xGnP Exfoliated Graphite NanoPlatelets—that makes plastic stiffer, lighter and stronger and could result in more fuel-efficient airplanes and cars as well as more durable medical and sports equipment and enhanced energy storage systems.
The key to the new material’s capabilities is a fast and inexpensive process for separating layers of graphite (graphene) into stacks less than 10 nanometers in thickness but with lateral dimensions anywhere from 500 nm to tens of microns, coupled with the ability to tailor the particle surface chemistry to make it compatible with water, resin or plastic systems.
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Air Force Office of Scientific Research Awards $3M for Research into Graphene Additives for Novel Aviation and Diesel Fuels
July 21, 2009
The US Air Force Office of Scientific Research (AFOSR) has awarded an interdisciplinary team of scientists led by Princeton engineers a two-year, $3-million grant to develop nanoscale graphene additives for novel fuels to help supersonic jets fly faster and diesel engines cleaner and more efficient.
The funding, which comes as part of the 2009 American Recovery and Reinvestment Act Research Program (funding opportunity AFOSR-BAA-2009-3), will be used to tackle a fundamental fuel barrier to designing faster supersonic aircraft.
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Australian Researchers Propose New MOF-based Concept for H2 and Methane Storage
July 20, 2009
| Schematic representation for proposed material Mg-C60@MOF showing a MOF cavity impregnated with magnesium-decorated C60. Credit: ACS. Click to enlarge. |
Researchers in Australia have proposed a new concept for hydrogen and methane storage materials involving the incorporation of magnesium-decorated fullerenes within metal-organic frameworks (MOFs). According to their modeling, the magnesium-decorated Mg10C60 fullerenes show a volumetric methane uptake of 265 v/v, the highest reported value for any material, which significantly exceeds the US Department of Energy target of 180 v/v.
They also predict a very high hydrogen adsorption enthalpy of 11 kJ mol-1 with relatively little decrease as a function of H2 filling. This value is close to the calculated optimum value of 15.1 kJ mol-1 and is achieved concurrently with saturation hydrogen uptake in large amounts at pressures under 10 atm.
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Ames Laboratory and Catilin Seek to Commercialize New Nanoparticle-Based Algal Oil Extraction Process
April 15, 2009
| An example of a mesoporous silica nanosphere (MSN). The mesoporous structure is illustrated by the hexagonally packed light-colored dots. Credit: Victor Lin. Click to enlarge. |
Researchers at the US Department of Energy’s Ames Laboratory and Iowa State University have developed a unique method that uses sponge-like mesoporous nanoparticles to harvest biofuel oils from algae without harming the algae. The nanofarming technology promises lower production costs and shorter production cycles.
Commercialization of this new technology is at the center of a Cooperative Research and Development Agreement (CRADA) between the Ames Laboratory and Catilin, a nanotechnology-based company that specializes in biofuel production (earlier post). The agreement targets development of this novel approach to reduce the cost and energy consumption of the industrial processing of non-food source biofuel feedstock.
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Nanotube Structures Could Improve Electric Motors
March 12, 2009
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| Carbon nanotube commutator. Source: Rice University. Click to enlarge. |
Researchers from Rice University and the University of Oulu in Oulu, Finland, have found that carbon nanotubes could significantly improve the performance of electrical commutators that are common in electric motors and generators.
The research, which appeared online this month in the journal Advanced Materials, finds that brush contact pads made of carbon nanotubes had 10 times less resistance than did the carbon-copper composite brushes commonly used today. Brush contacts are an integral part of commutators, or spinning electrical switches, used in many battery-powered electrical devices, such as cordless drills.
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New Nanoporous Material Has Highest Surface Area Yet
March 09, 2009
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| UMCM-2 is a coordination polymer comprising three different types of cages. Credit: ACS. Click to enlarge. |
Researchers at the University of Michigan (U-M) have developed a new nanoporous material with a surface area of more than 5,000 square meters per gram—significantly higher than that of any other porous material reported to date.
The work, by a team led by associate professor of chemistry Adam Matzger, is described in a paper published online 6 March in the Journal of the American Chemical Society.
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Nitrogen-Doped Carbon Nanotube Arrays Perform Better Than Platinum as Fuel Cell Catalysts
February 06, 2009
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| CO-poison effect on the i-t chronoamperometric response for Pt-C/GC and VA-NCNT/GC electrodes. The arrow indicates the addition of 55 mL/min CO gas into the 550 mL/min O2 flow. The mixture gas of ~9% CO (volume/volume) was then introduced into the electrochemical cell. From Gong et al. (2009) Click to enlarge. |
A team of researchers led by Liming Dai at the University of Dayton, Ohio, has found that arrays of vertically aligned nitrogen-containing carbon nanotubes (VA-NCNTs) can act as a metal-free electrode with a much better electrocatalytic activity, long-term operation stability, insensitivity to CO poisoning and tolerance to crossover effect than platinum for oxygen reduction in alkaline fuel cells.
The ability to replace costly platinum with a much lower-cost carbon-based catalyst could lead to more efficient fuel cells that can be affordably mass-produced. A paper on the findings was published in the 6 Feb issue of the journal Science.
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New Crystalline-Amorphous Core-Shell Silicon Nanowires for High Capacity and High Current Li-Ion Electrodes
January 21, 2009
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| Top: Schematic illustration of the lithiation of the Si c-a core-shell NWs. Bottom: Capacity and Coulombic efficiency over 100 cycles. Credit: ACS. Click to enlarge. |
A team of researchers from Stanford University and Università degli Studi di Milano-Bicocca, led by Stanford professor Yi Cui, have developed a core-shell design of crystalline-amorphous (c-a) silicon nanowires (NW) to enable higher power and longer-life lithium-ion battery electrodes. A paper describing the work was published in the 14 January issue of the ACS journal Nano Letters.
Silicon is an attractive alloy-type anode material for lithium-ion batteries because of its highest known capacity (4,200 mAh g-1). However, silicon’s large volume change upon lithium insertion and extraction, which causes pulverization and capacity fading, has limited its applications.
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Researchers Engineer Carbon Nanotube Scaffolds for Higher Density Hydrogen Storage
December 24, 2008
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| The procedure expands the geometry of a SWCNT fiber (upper left) and then locks the expanded form into a stable shape with cross linkers (bottom). Click to enlarge. Credit: ACS |
Researchers at Rice University and the National Renewable Energy Laboratory (NREL) have engineered single-walled carbon nanotube (SWCNT) fibers to become a scaffold for the storage of hydrogen. The 3-D nanoengineered fibers physisorb twice as much hydrogen per unit surface area as do typical macroporous carbon materials.
These fiber-based systems can have high density, and combined with the outstanding thermal conductivity of carbon nanotubes, can point a way toward solving the volumetric and heat-transfer constraints that limit some other hydrogen-storage supports, the team writes in a paper published online 22 December in the Journal of the American Chemical Society.
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DOE Selects Projects To Advance Nanomanufacturing; Catalysts, Coatings and Oher Nanostructured Materials
October 19, 2008
The US Department of Energy (DOE) has selected 20 project proposals for funding following its Nanomanufacturing for Energy Efficiency 2008 Research Call. The projects promise to make revolutionary improvements in a broad range of catalysts, coatings and other nanostructured materials for use in energy production, storage, and consumption applications that will reduce energy and carbon intensity in industrial processes.
An important next step in realizing the promise of nanotechnology is to improve production and manufacturing techniques for nanomaterials and nano-enabled products, many of which are “stuck at the lab scale.” The selected projects will advance the state of nanomanufacturing by improving the reliability of nanomaterials production and scaling-up manufacturing processes that use nanomaterials.
