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

A Tougher Tooth: A new dental restoration composite developed by UCSB scientists proves more durable than the conventional material August 22nd, 2017

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Tokai University research: Nanomaterial wrap for improved tissue imaging August 21st, 2017

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

Chemistry

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

2-faced 2-D material is a first at Rice: Rice University materials scientists create flat sandwich of sulfur, molybdenum and selenium August 14th, 2017

Clarifiying complex chemical processes with quantum computers August 3rd, 2017

Strem Chemicals Surpasses ChemStewards® Requirements: Strem Qualifies for SOCMA’s “Excellence” Ranking August 3rd, 2017

Discoveries

A Tougher Tooth: A new dental restoration composite developed by UCSB scientists proves more durable than the conventional material August 22nd, 2017

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Tokai University research: Nanomaterial wrap for improved tissue imaging August 21st, 2017

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

Announcements

A Tougher Tooth: A new dental restoration composite developed by UCSB scientists proves more durable than the conventional material August 22nd, 2017

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Tokai University research: Nanomaterial wrap for improved tissue imaging August 21st, 2017

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

Energy

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

Fewer defects from a 2-D approach August 15th, 2017

Automotive/Transportation

2-faced 2-D material is a first at Rice: Rice University materials scientists create flat sandwich of sulfur, molybdenum and selenium August 14th, 2017

Engineers pioneer platinum shell formation process – and achieve first-ever observation August 11th, 2017

GLOBALFOUNDRIES, Silicon Mobility Deliver the Industry’s First Automotive FPCU to Boost Performance for Hybrid and Electric Vehicles: Silicon Mobility and GF’s 55nm LPx -enabled platform, with SST’s highly-reliable SuperFlash® memory technology, boosts automotive performance, ene August 3rd, 2017

Rice U. scientists map ways forward for lithium-ion batteries for extreme environments: Paper details developments toward high-temperature batteries July 27th, 2017

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