Posted on 03/05/2007 9:16:51 AM PST by Neville72
Researchers at the U.S. Department of Energy's Argonne National Laboratory have developed an advanced concept in nanoscale catalyst engineering a combination of experiments and simulations that will bring polymer electrolyte membrane fuel cells for hydrogen-powered vehicles closer to massive commercialization. Sponsored Links (Ads by Google)
The results of their findings identify a clear trend in the behavior of extended and nanoscale surfaces of platinum-bimetallic alloy. Additionally, the techniques and concepts derived from the research program are expected to make overarching contributions to other areas of science well beyond the focus on electrocatalysis.
The Argonne researchers, Nenad Markovic and Vojislav Stamenkovic, published related results last month in Science and this month in Nature Materials on the behavior of single crystal and polycrystalline platinum alloy surfaces. The researchers discovered that the nanosegregated platinum-nickel alloy surface has unique catalytic properties, opening up important new directions for the development of active and stable practical cathode catalysts in fuel cells.
These scientific accomplishments together provide a solid foundation for the development of hydrogen-powered vehicles, as basic research brings value of society today by helping to lay the foundation for tomorrow's technological breakthroughs. "Understanding catalysis is a grand challenge of nanoscience that is now coming within reach," said George Crabtree, director of Argonne's Materials Science Division. "The systematic work that Voya and Nenad are doing is a major step toward transforming catalysis from an empirical art to a fundamental science."
Their experiments and approach sought to substantially improve and reduce platinum loading as the oxygen-reduction catalyst. The research identified a fundamental relationship in electrocatalytic trends on surfaces between the experimentally determined surface electronic structure (the d -band centre) and activity for the oxygen-reduction reaction. This relationship exhibits "volcano-type" behavior, where the maximum catalytic activity is governed by a balance between adsorption energies of reactive intermediates and surface coverage by spectator (blocking) species.
The electrocatalytic trends established for extended surfaces explain the activity pattern of nanocatalysts and provide a fundamental basis for the enhancement of cathode catalysts. By combining experiments with simulations in the quest for surfaces with desired activity, the researchers developed an advanced concept in nanoscale catalyst engineering.
"In the past, theoretical connections have been suggested between electronic behavior and catalytic activity," explained Markovic. "Our work represents the first time that the connections have been identified experimentally. For us, this development constitutes the beginning of more breakthrough advances in nanocatalysts."
According to Stamenkovic, "Our study demonstrates the potential of new analytical tools for characterizing nanoscale surfaces in order to fine tune their properties in a desired direction. We have identified a cathode surface that is capable of achieving and even exceeding the target for catalytic activity with improved stability. This discovery sets a new bar for catalytic activity of the cathodic reaction in fuel cells."
Through continued research combining nanoscale fabrication, electrochemical characterization and numerical simulation a new generation of multi-metallic systems with engineered nanoscale surfaces is on the horizon. Argonne's Center for Nanoscale Materials, Advanced Photon Source and Electron Microscopy Center will enable some of this research.
"We have got crucial support from Argonne management to set up the new labs and launch research directions, which would establish Argonne as a leading center in basic sciences related to energy conversion." said Stamenkovic.
Their lab includes a custom built three-chamber UHV system equipped with the state-of-the-art surface sensitive tools, including Low Energy Ion Scattering Spectroscopy (LEISS), Auger Electron Spectroscopy (AES), angle resolved X-ray photoemission spectroscopy (XPS with monochromator), ultraviolet photoelectron spectroscopy (UPS), Low Energy Electron Diffraction (LEED) optics, sputtering guns, thermal evaporators, dual hemispherical analyzers, and chamber with scanning tunneling microscopy (STM) and atomic force microscopy AFM. All three chambers are connected to each other but they can also work as independent chambers, making it possible to transfer samples from one to the other unit in order to get detailed surface characterization or to make desirable surface modification.
"We hope that this research program will lead the nation to more secure energy independence and a cleaner environment for future generations," Markovic said.
Hydrogen is not a fuel - it is a (poor) storage medium.
I swear the folks in the media think like that.
Hydrogen=highly explosive
Oxygen=good for fires
putting all of that into a vehicle=car bomb
I would NEVER drive one of those around. I like my safety, thank you very much.
Hydrogen is a fuel, in that when combined with the buzzword, "Nanoscale" , it fuels funding proposals and IPOs.
I have oxygen and acetylene i store together. Makes a great cutting torch. They are pretty damn safe, too.
This is not the real problem with hydrogen. It's the wasted energy need to make it when there are better alternatives.
They are comming around: Going Nuclear A Green Makes the Case
The real question is whether we will have to restrict sales to Iran, Syria, etc.
....and can anyone guess who will produce all this hydrogen?
Anyone have any hydrogen trees in their back yards?
Like every knucklehead knows, the hydrogen has to come from water. Sure, you can steam-reform hydrocarbons, but what's the point? You'd still need imported oil or natural gas as a feedstock.
Unfortunately, environmentalist knuckleheads don't understand that the laws of thermodynamics require that it will take more energy to separate the H2 from the O than you could ever get by recombining them in a fuel cell. If Congress weren't controlled by BIG OIL, it would repeal the laws of thermodynamics. That's the only way launch the hydrogen economy.
Repeat...hydrogen is NOT fuel. It is a store of energy that is always converted at a loss. Using gasoline in an engine is more efficient than chemically converting that gasoline to hydrogen or burning the gasoline to generate electricity to hydrolyze water to hydrogen. The only advantage to hydrogen is the clean "burn" at the point of final use. The space station is a nice place for hydrogen. Creating hydrogen always involves another source of energy. That conversion creates pollutants up front, so the net pollution picture with hydrogen is worse than just using the original energy source.
Given the problem with storing hydrogen, you might waste lots of energy to leakage and show no overall value for the up front pollution created in its generation.
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