Science Current Events | Science News | Brightsurf.com
 
Email a Friend Send to a friend
Printer Friendly Print Nanowires May Lead To Better Fuel Cells

Nanowires May Lead To Better Fuel Cells

March 12, 2009

The creation of long platinum nanowires at the University of Rochester could soon lead to the development of commercially viable fuel cells.

Described in a paper published today in the journal Nano Letters, the new wires should provide significant increases in both the longevity and efficiency of fuel cells, which have until now been used largely for such exotic purposes as powering spacecraft. Nanowire enhanced fuel cells could power many types of vehicles, helping reduce the use of petroleum fuels for transportation, according to lead author James C. M. Li, professor of mechanical engineering at the University of Rochester.




"People have been working on developing fuel cells for decades. But the technology is still not being commercialized," says Li. "Platinum is expensive, and the standard approach for using it in fuel cells is far from ideal. These nanowires are a key step toward better solutions."

The platinum nanowires produced by Li and his graduate student Jianglan Shui are roughly ten nanometers in diameter and also centimeters in length-long enough to create the first self-supporting "web" of pure platinum that can serve as an electrode in a fuel cell.

Much shorter nanowires have already been used in a variety of technologies, such as nanocomputers and nanoscale sensors. By a process known as electrospinning-a technique used to produce long, ultra-thin solid fibers-Li and Shui were able to create platinum nanowires that are thousands of times longer than any previous such wires.

"Our ultimate purpose is to make free-standing fuel cell catalysts from these nanowires," says Li.

Within a fuel cell the catalyst facilitates the reaction of hydrogen and oxygen, splitting compressed hydrogen fuel into electrons and acidic hydrogen ions. Electrons are then routed through an external circuit to supply power, while the hydrogen ions combine with electrons and oxygen to form the "waste" product, typically liquid or vaporous water.

Platinum has been the primary material used in making fuel cell catalysts because of its ability to withstand the harsh acidic environment inside the fuel cell. Its energy efficiency is also substantially greater than that of cheaper metals like nickel.

Prior efforts in making catalysts have relied heavily on platinum nanoparticles in order to maximize the exposed surface area of platinum. The basic idea is simple: The greater the surface area, the greater the efficiency. Li cites two main problems with the nanoparticle approach, both linked to the high cost of platinum.

First, individual particles, despite being solid, can touch one another and merge through the process of surface diffusion, combining to reduce their total surface area and energy. As surface area decreases, so too does the rate of catalysis inside the fuel cell.

Second, nanoparticles require a carbon support structure to hold them in place. Unfortunately, platinum particles do not attach particularly well to these structures, and carbon is subject to oxidization, and thus degradation. As the carbon oxidizes over time, more and more particles become dislodged and are permanently lost.

Li's nanowires avoid these problems completely.

With platinum arranged into a series of centimeter long, flexible, and uniformly thin wires, the particles comprising them are fixed in place and need no additional support. Platinum will no longer be lost during normal fuel cell operation.

"The reason people have not come to nanowires before is that it's very hard to make them," says Li. "The parameters affecting the morphology of the wires are complex. And when they are not sufficiently long, they behave the same as nanoparticles."

One of the key challenges Li and Shui managed to overcome was reducing the formation of platinum beads along the nanowires. Without optimal conditions, instead of a relatively smooth wire, you end up with what looks more like a series of interspersed beads on a necklace. Such bunching together of platinum particles is another case of unutilized surface area.

"With platinum being so costly, it's quite important that none of it goes to waste when making a fuel cell," says Li. "We studied five variables that affect bead formation and we finally got it-nanowires that are almost bead free."

His current objective is to further optimize laboratory conditions to obtain fewer beads and even longer, more uniformly thin nanowires. "After that, we're going to make a fuel cell and demonstrate this technology," says Li.

The University of Rochester



Related Nanowires Current Events and Nanowires News Articles Nanowires Current Events and Nanowires News RSS Nanowires Current Events and Nanowires News RSS
LANL Roadrunner simulates nanoscale material failure
Very tiny wires, called nanowires, made from such metals as silver and gold, may play a crucial role as electrical or mechanical switches in the development of future-generation ultrasmall nanodevices.

Science at the Petascale: Roadrunner Results Unveiled
The world's fastest supercomputer, Roadrunner, at Los Alamos National Laboratory has completed its initial "shakedown" phase doing accelerated petascale computer modeling and simulations of a variety of unclassified, fundamental science projects.

Transforming Nanowires Into Nano-Tools Using Cation Exchange Reactions
A team of engineers from the University of Pennsylvania has transformed simple nanowires into reconfigurable materials and circuits, demonstrating a novel, self-assembling method for chemically creating nanoscale structures that are not possible to grow or obtain otherwise.

Berkeley researchers create first hyperlens for sound waves
Ultrasound and underwater sonar devices could "see" a big improvement thanks to development of the world's first acoustic hyperlens. Created by researchers with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), the acoustic hyperlens provides an eightfold boost in the magnification power of sound-based imaging technologies.

Nanowire biocompatibility in the brain: So far so good
The biological safety of nanotechnology, in other words, how the body reacts to nanoparticles, is a hot topic. Researchers at Lund University in Sweden have managed for the first time to carry out successful experiments involving the injection of so-called 'nanowires.'

Harvard scientists bend nanowires into 2-D and 3-D structures
Taking nanomaterials to a new level of structural complexity, scientists have determined how to introduce kinks into arrow-straight nanowires, transforming them into zigzagging two- and three-dimensional structures with correspondingly advanced functions.

Putting a Strain on Nanowires Could Yield Colossal Results
In finally answering an elusive scientific question, researchers with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have shown that the selective placement of strain can alter the electronic phase and its spatial arrangement in correlated electron materials.

Friction force differences could offer a new means for sorting and assembling nanotubes
Nanotubes and nanowires are promising building blocks for future integrated nanoelectronic and photonic circuits, nanosensors, interconnects and electro-mechanical nanodevices. But some fundamental issues remain to be resolved - among them, how to position and manipulate the tiny tubes.

Making more efficient fuel cells
Bacteria that generate significant amounts of electricity could be used in microbial fuel cells to provide power in remote environments or to convert waste to electricity.

Caltech and IBM scientists use self-assembled DNA scaffolding to build tiny circuit boards
Scientists at the California Institute of Technology (Caltech) and IBM's Almaden Research Center have developed a new technique to orient and position self-assembled DNA shapes and patterns-or "DNA origami"-on surfaces that are compatible with today's semiconductor manufacturing equipment.
More Nanowires Current Events and Nanowires News Articles
Enhanced Field Emission from Metallic Surfaces and Nanowires

Enhanced Field Emission from Metallic Surfaces and Nanowires
by Arti Dangwal-Pandey (Author)

The role of material properties, surface preparation and cleaning techniques on Nb and Cu was studied for EFE , which is disastrous for high field vacuum devices. Dry ice cleaning is found to suppress EFE from the metallic surfaces very efficiently. High purity single crystal and large grain Nb samples showed the onset of FE at high fields (120 ? 200 MV/m).For the first time, the grain boundary assisted field emission was observed for Nb. A correlationbetween size of emitters and onset fields is obtained, which sets a threshold for the tolerable defect size to achieve the envisaged accelerating gradients in cavities reliably.Additionaly, the systematic study performed on electrochemically deposited Cu, Ni and Au nanowires of different aspect ratios and spatial distribution for cold...

Oakley Men's Nanowire 4.0 Iridium Polarized Sunglasses,Matte Black Frame/Black Lens,one size

Oakley Men's Nanowire 4.0 Iridium Polarized Sunglasses,Matte Black Frame/Black Lens,one size
by Oakley

Frame : Matte Black , Lenses : Black , Iridium Polarized  ,

Oakley Polarized Nanowire 3.0 Olive Chrome / Tungsten Iridium

Oakley Polarized Nanowire 3.0 Olive Chrome / Tungsten Iridium
by Oakley

Plutonite material for supreme visual clarity O-Matter frame material offers superb construction quality 100 percent UVA/UVB filtration Optical clarity exceeds all ANSI Z87.1 standards

Oakley Men's Nanowire 3.0 Iridium Polarized Sunglasses,Polished Black Frame/Black Lens,one size

Oakley Men's Nanowire 3.0 Iridium Polarized Sunglasses,Polished Black Frame/Black Lens,one size
by Oakley

OAKLEY NANOWIRE 3.0 POLARIZED 12-919 SUNGLASSES FRAME: POLISHED BLACK LENS: BLACK IRIDIUM POLARIZED MODEL # 12-919

Oakley Oakley Nanowire 2.0 Men's Polarized Active Race Wear Sunglasses - Color: Pewter/Black Iridium, Size: One Size Fits All

Oakley Oakley Nanowire 2.0 Men's Polarized Active Race Wear Sunglasses - Color: Pewter/Black Iridium, Size: One Size Fits All
by Oakley

Our athletes spend a lot of time defying gravity, so we figured they should have a lifestyle sunglass that does the same. It's made of an ultra-lightweight titanium alloy that lets us create sculptural contours without sacrificing flexibility, so even if you're just competing in the rat race, you can take advantage of memory metal that offers an adaptable fit. But the real marvel of engineering is the way we packed so much innovation into so light a frame.

The unbeatable clarity of HIGH DEFINITION OPTICS (HDO) has been matched with the finest technologies ever to tame light rays. OAKLEY NANOWIRE blocks glare with 99% polarization efficiency, thanks to the best polarized lenses on the planet. Our permanent HYDROPHOBIC lens coating repels water, skin oils and dust. IRIDIUM lens...

Oakley Nanowire 1.0 Black Chrome/VR28 Black Iridium Polarized

Oakley Nanowire 1.0 Black Chrome/VR28 Black Iridium Polarized
by Oakley

Frame:Black Chrome Lenses:VR28 Black Iridium Polarized

  SNAP yields high density circuits. (Electronics and Magnetics).(superlattice nanowire pattern transfer): An article from: Nanoparticle News
by Business Communications Company, Inc. (Publisher)

This digital document is an article from Nanoparticle News, published by Business Communications Company, Inc. on May 1, 2003. The length of the article is 819 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser.

Citation Details
Title: SNAP yields high density circuits. (Electronics and Magnetics).(superlattice nanowire pattern transfer)
Publication: Nanoparticle News (Magazine/Journal)
Date: May 1, 2003
Publisher: Business Communications Company, Inc.
Volume: 6 Issue: 4 Page: 3(3)

Distributed by Thomson...

Oakley Men's Nanowire 2.0 Iridium Polarized Sunglasses,Polished Black Frame/VR28 Black Lens,one size

Oakley Men's Nanowire 2.0 Iridium Polarized Sunglasses,Polished Black Frame/VR28 Black Lens,one size
by Oakley

Plutonite material for supreme visual clarity O-Matter frame material offers superb construction quality 100 percent UVA/UVB filtration Optical clarity exceeds all ANSI Z87.1 standards

Nanowires and Nanobelts: Materials, Properties and Devices: Volume 2: Nanowires and Nanobelts of Functional Materials

Nanowires and Nanobelts: Materials, Properties and Devices: Volume 2: Nanowires and Nanobelts of Functional Materials
by Zhong Lin Wang (Editor)

Nanowires, nanobelts, nanoribbons, nanorods ..., are a new class of quasi-one-dimensional materials that have been attracting a great research interest in the last few years. These non-carbon based materials have been demonstrated to exhibit superior electrical, optical, mechanical and thermal properties, and can be used as fundamental building blocks for nano-scale science and technology, ranging from chemical and biological sensors, field effect transistors to logic circuits. Nanocircuits built using semiconductor nanowires demonstrated were declared a "breakthrough in science" by Science magazine in 2001. Nature magazine recently published a report claiming that "Nanowires, nanorods, nanowhiskers, it does not matter what you call them, they are the hottest property in nanotechnology"...

Oakley Nanowire 1.0 Men's Polarized Active Lifestyle Racewear Sunglasses - Color: Brown Chrome/Tungsten Iridium, Size: One Size Fits All

Oakley Nanowire 1.0 Men's Polarized Active Lifestyle Racewear Sunglasses - Color: Brown Chrome/Tungsten Iridium, Size: One Size Fits All
by Oakley



© 2009 BrightSurf.com