Dr. Iulian Dugulan: 'Gamma rays show catalysts at work' - Photo: Tomas van Dijk
Modest as it may be, the Mössbauer lab at the Reactor Institute does what no other Dutch lab can: it shows chemical catalysts in action under industrial conditions.
This unique feature is what brought chemical researchers Hirsa Torres
Galvis (MSc) and Professor Krijn de Jong from Utrecht University here. They wanted to improve their understanding of the iron nanoparticle catalysts they’re developing, in order to make short hydrocarbons, called lower olefins, from biomass. These lower olefins function as a base chemical for the production of plastics, cosmetics and drugs. The work done by the team opens up the possibility of using sustainable feedstock for the chemical and pharmaceutical industries, instead of fossil oil. And that generated a lot of interest. The Utrecht team published their results in last week’s Science magazine. Among the article’s authors is the name of Dr Iulian Dugulan, from the Reactor Institute Delft.
As Dugulan (Applied Sciences) shows us the lab with lead-shielded benches, he says that the current measurements are being done for Shell. They are studying the catalytic conversion of synthesis gas into cleaner liquid fuels. Because of the gamma rays involved, the interview will be conducted elsewhere.
The key technology here is called Mössbauer spectroscopy. It is based on a discovery by the German physicist, Rudolf Mössbauer, in 1958 (Nobel Prize 1961), which found that gamma rays could be used ‘as a probe to observe the effects of interactions between a nucleus and its electrons and those of its neighbours’ (Wikipedia). In other words: high energy gamma photons probe the energy differences that derive from different chemical bindings in astonishing resolution. Too complicated to explain in any detail here, Dugulan says that Mossbauer spectroscopy “shows the catalysts at work”.
When gamma rays are sent through a sample, the energy spectrum of the transmitted radiation is like a fingerprint that allows identification of the catalyst in use. “It gives you information on the structural properties of the sample, on the oxidation state and on the magnetic properties of the metal particles”, Dugulan explains. To a bystander, the narrow dips in the spectrum may not seem like much; however, an expert sees how active a catalyst is and how it degrades by sintering, poisoning or carbon deposition. “Only if we understand how a new catalyst works, can we improve its performance,” Dugulan concludes.
Hirsa M. Torres Galvis et. al., ‘Supported Iron Nanoparticles as Catalysts for Sustainable Production of Lower Olefines’, Science, 17 February 2012
