http://www.anl.gov/Media_Center/News/2011/news111208.htmlMaking molecular hydrogen more efficiently
December 8 , 2011.
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Researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory have developed an extraordinarily efficient two-step process that electrolyzes, or separates, hydrogen atoms from water molecules before combining them to make molecular hydrogen (2), which can be used in any number of applications from fuel cells to industrial processing.
Easier routes to the generation of hydrogen have long been a target of scientists and engineers, principally because the process to create the gas requires a great deal of energy. Approximately 2 percent of all electric power generated in the United States is dedicated to the production of molecular hydrogen, so scientists and engineers are searching for any way to cut that figure. "People understand that once you have hydrogen you can extract a lot of energy from it, but they don't realize just how hard it is to generate that hydrogen in the first place," said Nenad Markovic, an Argonne senior chemist who led the research.
While a great deal of hydrogen is created by reforming natural gas at high temperatures, that process creates carbon-dioxide emissions. "Water electrolyzers are by far the cleanest way of producing hydrogen," Markovic said. "The method we've devised combines the capabilities of two of the best materials known for water-based electrolysis."
Most previous experiments in water-based electrolysis rely on special metals, like platinum, to adsorb and recombine reactive hydrogen intermediates into stable molecular hydrogen. Markovic's research focuses on the previous step, which involves improving the efficiency by which an incoming water molecule would disassociate into its fundamental components. To do this, Markovic and his colleagues added clusters of a metallic complex known as nickel-hydroxide—Ni(OH)2. Attached to a platinum framework, the clusters tore apart the water molecules, allowing for the freed hydrogen to be catalyzed by the platinum.
…http://dx.doi.org/10.1126/science.1211934