ARGONNE, ILL. (Sept. 6, 2012) -- Using ultrafast X-rays, scientists for the first time have watched how quickly electrons hop their way through rust nanoparticles.
This gives key insight to how iron oxide, one of the most abundant minerals in soil, behaves and alters the condition of soil and water around it. This also demonstrates the potential of time-resolved X-ray and optical methods to study chemical reactions at the subnanoscale in other semiconductors.
Scientists have long known that certain minerals, redox active ions and biological proteins can exchange electrons to initiate chemical changes in the mineral. But the process of how electrons hop from atom to atom inside a nanoparticle to facilitate change has been too fast to see until now. The same process controls charge collection in solar energy devices involving metal oxides, and thus this work may have relevance to new energy technologies.
Using the Advanced Photon Source and Center for Nanoscale Materials at the Department of Energy's Argonne National Laboratory, an international team of scientists from Lawrence Berkeley National Laboratory and Argonne, the Technical University of Denmark, Pacific Northwest National Laboratory, and the Polish Academy of Sciences detailed how electrons hop inside iron particles. This plays a significant role in controlling how the iron reacts with the environment.
Iron is an integral part of the natural environment and many important chemical reactions involve changes in iron that are caused by an electron being transferred to the iron from other minerals, water or biological agents. Electron transfer to iron(III) oxides creates iron(II) sites in the mineral. But the iron(II) site is not fixed, as the electron can hop to other sites. Because iron(II) is more soluble than iron(III), when an electron hops to an iron atom at the mineral surface, that iron(II) atom can be released into solution, and dramatically affect the che
|Contact: Tona Kunz |
DOE/Argonne National Laboratory