Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > UCLA solution to chemical mystery could yield more efficient hydrogen cars

Abstract:
Environmentally friendly vehicles that use hydrogen gas can dramatically reduce greenhouse emissions and lessen the country's dependence on fossil fuels. While several hydrogen-fueled vehicles are currently on the market, there is still much room for improvement in the way they store and utilize hydrogen gas.

UCLA solution to chemical mystery could yield more efficient hydrogen cars

LOS ANGELES, CA | Posted on February 27th, 2008

Now researchers at the UCLA Henry Samueli School of Engineering and Applied Science, using molecular dynamics simulations, have solved a decade-old mystery, and their findings could eventually lead to commercially practical designs of storage materials for use in hydrogen vehicles. Their research, currently available on the Web site of Proceedings of the National Academy of Sciences, will be published in the journal's print edition March 4.

With current technologies, hydrogen gas storage tanks have to be as large as or larger than the trunk of a car to carry enough fuel for a vehicle to travel only 100 to 200 miles. While liquid hydrogen is denser than gas and takes up less space, it is expensive, difficult to produce and reduces the environmental benefits of hydrogen vehicles. Widespread commercial acceptance of hydrogen vehicles has therefore hinged on finding materials that can store hydrogen gas at high volumetric and gravimetric densities in reasonably sized, lightweight fuel tanks.

The search for solutions has generally involved the use of metal hydrides metal alloys that absorb and store hydrogen within their structure and release the hydrogen when subjected to heat.

In 1997, scientists discovered that adding a small amount of titanium to sodium alanate, a well-known metal hydride used in onboard hydrogen gas storage, not only lowered the temperature of the hydrogen released, making the reaction more efficient, but it also allowed for easier refueling and storage of high-density hydrogen at reasonable pressures and temperatures. In fact, the weight-percent of stored hydrogen was instantly doubled in comparison with other inexpensive materials.

"Nobody really understood what the titanium did," said the UCLA study's lead author, Vidvuds Ozolins, an associate professor of material science and engineering and a member of UCLA's California NanoSystems Institute. "The chemical processes and the mechanisms were really a mystery."

Using computers and the power of basic physics, chemistry and quantum mechanics, Ozolins' group decided to take a step back and examine sodium alanate in its pure form, without added titanium. The group analyzed the atomic processes occurring in the material and what happens to the chemical bond between the hydrogen and the material at the temperatures of hydrogen release. The computation gave the researchers information that would have been very difficult to obtain experimentally.

Their findings suggest that the reaction mechanism essential for the extraction of hydrogen from sodium alanate involves the diffusion of aluminum ions within the bulk of the hydride. By comparing the calculated activation energies to the experimentally determined values, Ozolins' group found that aluminum diffusion is the key rate-limiting process in materials catalyzed with titanium. Thus, titanium facilitates processes in the material that are essential for turning on this mechanism and extracting hydrogen at lower temperatures.

"This method and this knowledge can now be used to analyze other materials that would make for better storage systems than sodium alanate," said Hakan Gunaydin, a UCLA graduate student in Ozolins' lab and one of the study's authors. "We are still on the fundamental end of the study. But if we can figure this out computationally, the people with the technology in engineering can figure out the rest."

"Sodium alanate in itself is a prototypical complex hydride with a reasonable storage density and very good kinetics," Ozolins said. "Hydrogen goes in and comes out quickly, but it wouldn't be practical for a car, simply because it doesn't contain enough hydrogen. So that's why we are so interested in understanding how the hydrogen comes out, what happens exactly and how we can take this to other materials."

What Ozolins' group along with UCLA chemistry and biochemistry professor Kendall Houk, also a member of the California NanoSystems Institute hopes to do now is to apply the methods and lessons learned to those materials that would make for a commercially practical hydrogen gas storage system. They hope their findings will one day facilitate the design and creation of an affordable and environmentally friendly hydrogen vehicle.

The study was funded by the U.S. Department of Energy and the National Science Foundation.

####

About UCLA
The UCLA Henry Samueli School of Engineering and Applied Science, established in 1945, offers 28 academic and professional degree programs, including an interdepartmental graduate degree program in biomedical engineering. Ranked among the top 10 engineering schools at public universities nationwide, the school is home to seven multimillion-dollar interdisciplinary research center in space exploration, wireless sensor systems, nanotechnology, nanomanufacturing and nanoelectronics, all funded by federal and private agencies.

For more information, please click here

Contacts:
Wileen Wong Kromhout
(310) 206-0540

Copyright © UCLA

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Forces of nature: Interview with microscopy innovators Gerd Binnig and Christoph Gerber August 26th, 2016

A promising route to the scalable production of highly crystalline graphene films August 26th, 2016

Graphene under pressure August 26th, 2016

New electrical energy storage material shows its power: Nanomaterial combines attributes of both batteries and supercapacitors August 25th, 2016

Chemistry

A new way to display the 3-D structure of molecules: Metal-organic frameworks provide a new platform for solving the structure of hard-to-study samples August 21st, 2016

Researchers watch catalysts at work August 19th, 2016

Pokhara, the second largest city of Nepal, to host its first ever International Meeting on Material Sciences and Engineering August 15th, 2016

'Liquid fingerprinting' technique instantly identifies unknown liquids: Ability to instantly identify unknown liquids in the field could aid first responders, improve plant safety August 4th, 2016

Discoveries

A promising route to the scalable production of highly crystalline graphene films August 26th, 2016

Graphene under pressure August 26th, 2016

Johns Hopkins scientists track metabolic pathways to find drug combination for pancreatic cancer August 25th, 2016

New electrical energy storage material shows its power: Nanomaterial combines attributes of both batteries and supercapacitors August 25th, 2016

Announcements

Forces of nature: Interview with microscopy innovators Gerd Binnig and Christoph Gerber August 26th, 2016

A promising route to the scalable production of highly crystalline graphene films August 26th, 2016

Graphene under pressure August 26th, 2016

Nanofiber scaffolds demonstrate new features in the behavior of stem and cancer cells August 25th, 2016

Energy

New electrical energy storage material shows its power: Nanomaterial combines attributes of both batteries and supercapacitors August 25th, 2016

Lehigh engineer discovers a high-speed nano-avalanche: New findings published in the Journal of Electrochemical Society about the process involving transformations in glass that occur under intense electrical and thermal conditions could lead the way to more energy-efficient glas August 24th, 2016

New flexible material can make any window 'smart' August 23rd, 2016

Researchers reduce expensive noble metals for fuel cell reactions August 22nd, 2016

Automotive/Transportation

Researchers reduce expensive noble metals for fuel cell reactions August 22nd, 2016

Researchers watch catalysts at work August 19th, 2016

Stanford-led team reveals nanoscale secrets of rechargeable batteries August 8th, 2016

New X-Ray microscopy technique images nanoscale workings of rechargeable batteries: Method developed at Berkeley Lab's Advanced Light Source could help researchers improve battery performance August 7th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic