Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanowires May Lead To Better Fuel Cells

13.03.2009
The creation of long platinum nanowires at the University of Rochester could soon lead to the development of commercially viable fuel cells by providing significant increases in both the longevity and efficiency. Nanowire enhanced fuel cells could power many types of vehicles, helping reduce the use of petroleum fuels for transportation.

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.

About the University of Rochester

The University of Rochester (www.rochester.edu) is one of the nation's leading private universities. Located in Rochester, N.Y., the University gives students exceptional opportunities for interdisciplinary study and close collaboration with faculty through its unique cluster-based curriculum. Its College of Arts, Sciences, and Engineering is complemented by the Eastman School of Music, Simon School of Business, Warner School of Education, Laboratory for Laser Energetics, Schools of Medicine and Nursing, and the Memorial Art Gallery.

Evan Wendel | Newswise Science News
Further information:
http://www.rochester.edu

More articles from Power and Electrical Engineering:

nachricht A big nano boost for solar cells
18.01.2017 | Kyoto University and Osaka Gas effort doubles current efficiencies

nachricht Multiregional brain on a chip
16.01.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>