This release is available in German.
Most people value large chunks of gold but scientists at the Vienna University of Technology are interested in gold at the smallest possible scale, because single gold atoms are potentially the most reactive catalysts for chemical reactions. However, when gold atoms are placed on a surface they tend to ball up into tiny nuggets consisting of several atoms. A team of surface scientists now managed to fix single gold atoms on special sites of an iron-oxide surface. This could open the door to more efficient catalysts, requiring less of the precious material.
Gold Does Not Like to Be Alone
Gold is a noble metal and does not usually bond with other elements, but as a catalyst it facilitates chemical reactions. It can, for example, facilitate the conversion of poisonous carbon monoxide to carbon dioxide. The effectiveness of gold as a catalyst depends on the size of the gold particles. Some evidence suggests that it works best if the gold is present in the form of single atoms. So far, however, this could not be studied in detail. "If individual gold atoms are put on a surface, they usually cluster up, forming nanoparticles", says Gareth Parkinson, who oversaw the experiments in the research group of Professor Ulrike Diebold at the Institute for Applied Physics at the TU Vienna.
Hot Surfaces Loose Atoms
Higher temperatures lead to a higher mobility of the gold atoms, so in order to stop the atoms from clustering, most surfaces must be cooled to a temperature so low that the desired chemical reactions would stop entirely. The researchers at the TU Vienna found a special kind of iron-oxide surface, which locks the single gold atoms in place.
A Good Place to Settle Down
The key to success is a slight deformation of the iron-oxide crystal structure. T
|Contact: Florian Aigner|
Vienna University of Technology