| Research
|
The fusion reactors that will someday power the electric grid and interplanetary spacecraft that will explore the solar system represent some of science's toughest materials challenges. Steve Zinkle has spent more than two decades at DOE's Oak Ridge National Laboratory studying radiation's effects on materials toward developing advanced materials for these missions. The UT-Battelle corporate fellow and Materials Science & Technology Division director says knowing the physical processes behind and nature of the damage is critical to the development of the high-performance, degradation-resistant materials required for fusion reactors and for fission-powered spacecraft. “I've spent a majority of my research career on fusion materials--20 years or so—investigating the physical phenomena responsible for radiation damage; to understand it well enough to prevent undesirable degradation from happening in suitably designed materials,” the materials scientist says. “Fusion creates one of the most hostile environments imaginable—a fusion reactor is a miniature sun surrounded by earthly materials,” Zinkle says. “Nuclear transmutation reactions and radiation damage events that would never happen with fission can become a big problem for fusion materials,” he says. The space reactor program presents fission materials problems. The power systems now in space service generate just a few kilowatts. If we want to explore the solar system in more depth—for example, investigate the frozen oceans on Jupiter's moon Europa and transmit reams of scientific data back to Earth, or establish human research bases on the moon or Mars, the spacecraft will need more power. The keys to developing more robust space reactors that can stand the radiological stresses and are sleek enough to launch on a rocket lie in advanced materials. Zinkle's contributions were recognized recently as he received DOE's prestigious E.O. Lawrence Award.Submitted by DOE's Oak Ridge National Laboratory |
|||||||||||||||||||||||||
|
Check out the Office of Science's new Website.
|
A boost for hydrogen
|
 |
| PEM fuel cells consist of electrodes containing a platinum catalyst and a solid polymer electrolyte. By splitting hydrogen molecules at the anode, and oxygen molecules at the cathode, PEM fuel cells generate an electrical current with only heat and water as a by-product. |
“The existing limitations facing PEM fuel cell technology applications in the transportation sector could be eliminated with the development of stable cathode catalysts with several orders of magnitude increase in activity over today's state-of-the-art catalysts, and that is what our discovery has the potential to provide,” said Vojislav Stamenkovic, a scientist with dual appointments at Berkeley Lab and Argonne.
Stamenkovic and Argonne senior scientist Nenad Markovic led a study in which pure single crystals of platinum-nickel alloys were created across a range of atomic lattice structures in an ultra-high vacuum (UHV) chamber. A combination of surface-sensitive probes and electrochemical techniques was then used to measure the respective abilities of these crystals to perform oxygen reduction reaction (ORR) catalysis. The ORR activity of each sample was then compared to that of platinum single crystals and platinum-carbon catalysts. The researchers identified the platinum-nickel alloy configuration Pt 3 Ni(111) as displaying the highest ORR activity that has ever been detected on a cathode catalyst—10 times better than a single crystal surface of pure platinum(111), and 90 times better than platinum-carbon.
Hydrogen-powered PEM fuel cells are favored for their potential use in vehicles because they can deliver high power in a relative small, light-weight device, and generate electricity while producing only water as a byproduct.
Submitted by DOE's
Lawrence Berkeley
National Laboratory