March 15, 2013
Scientists Watch Live Chemical Reactions For First Time
redOrbit Staff & Wire Reports - Your Universe Online
Using an extremely fast and extremely powerful X-ray laser, researchers have successfully observed how a catalyst behaves during a chemical reaction — work that they claim could be an important step forward in the search for cleaner and more efficient sources of energy.
Catalysts are substances that modify and increase the rate of a chemical reaction without being consumed in the process, and they are essential to the production of many different types of biological and synthetic chemicals.
Now, for the first time, an international group of researchers has been able to directly verify that there is a state of transition during which the molecules involved in the reaction hover above these change-causing agents for a short amount of time before flying off.
Furthermore, their work opens up the possibility to see live pictures of these ultrafast processes and could also provide new insight into the study of chemical reactions, the scientists explained on Thursday.
Study leaders Martina Dell'Angela and Wilfried Wurth of the Advanced Study Group of the University of Hamburg and colleagues used Stanford´s Linac Coherent Light Source (LCLS) free electron laser facility and computer simulations during their research.
The LCLS, which is housed at the US Department of Energy´s SLAC National Accelerator Laboratory in California, was used to reveal new information about a short-lived early state in chemical reactions occurring at the surface of catalyst samples.
Specifically, the team examined the accumulation of carbon monoxide on a catalyst surface made out of ruthenium, a rare type of transition metal. Dell´Angela and her colleagues were able to witness in unprecedented detail how the carbon monoxide molecules disconnected from the ruthenium surface.
“The molecule does not just fly away. It remains above the surface for a moment in a weakly bound state of transition in which it still interacts with the surface,” she explained. “This is important, for example, to understand, how new molecules find a place on an almost full catalyst surface.”
“This short-lived state of transition was already postulated more than half a century ago. Now, for the first time, it could actually be observed,” added Wurth. “With this study we verified that the observation of these processes is possible with X-ray lasers. This also opens up the possibility to investigate much more complex reactions.”
In addition to the University of Hamburg researchers, other members of the team were affiliated with SLAC and Stanford University in the US, the Center for Free-Electron Laser Science (CFEL); the Helmholtz-Zentrum Berlin for Materials and Energy, University of Potsdam and Fritz-Haber Institute of the Max Planck Society in Germany; Stockholm University in Sweden; and the Technical University of Denmark.
Their findings have been published in the March 15 edition of the journal Science.
“To study a reaction like this in real time is a chemist's dream,” Anders Nilsson, deputy director of the Stanford/SLAC Sustainable Energy through Catalysis (SUNCAT) Center for Interface Science and Catalysis, said in a statement. “We are really jumping into the unknown.”