Posted: December 22, 2009

New techniques allow to make perfect catalysts

(Nanowerk News) Baking the perfect soufflé depends on timing, good ingredients and the right proportions. Exactly the same thing applies to catalysts - the materials that make a chemical reaction work faster or better. Dutch-sponsored researcher Leticia Espinosa Alonso now knows how to make a perfect catalyst, thanks to new techniques.
Catalysts are used on a large scale to influence the speed of chemical reactions. They are used in the manufacture of fuels and also, for instance, in the preparation of foods such as margarine. However, in order to be able to take best advantage of the endless possibilities offered by catalysts, we need to know how the preparation of these materials works. Leticia Espinosa Alonso put catalysts under the microscope and discovered a world of new possibilities.
Espinosa Alonso, a chemist, used four different spectroscopic techniques to study catalysts in the course of their preparation: UV-VIS-NIR-microspectroscopy, IR microspectroscopy, magnetic resonance imaging (MRI) and tomographic energy dispersive diffraction imaging (TEDDI). MRI and TEDDI are already frequently used in other research fields, but they are not commonly used to study the preparation of catalysts.
Thanks to the various techniques, Espinosa Alonso succeeded in following the preparation of the materials in space and time. This time and space resolution was needed because the active particles in the catalyst bodies did not stay in the same place throughout the entire preparation process. The ultimate performance of the catalyst depends, however, on where these active particles are situated. Being able to monitor and influence these movements is therefore vital.
The active particles can be distributed in a number of ways: they might be spread uniformly across the whole catalyst body, or cling like an eggshell to the outer surface, or sit in a wide ring like an egg white within the body, and they can even be found like a yolk in the middle of the egg. So, although the ingredients are exactly the same, the distribution makes a world of difference: for instance, you can't use eggshell in a soufflé, and lots of catalysts are ineffective if the particles are situated around the edge.
Espinosa Alonso managed to study this distribution in detail for each type, and even managed to alter the distribution of palladium in an alumina pellet from eggshell to egg yolk. She also managed to distribute nickel as an eggshell, which is extremely difficult. Thanks to her insights, new and improved catalysts can now be developed.
With her research, Espinosa Alonso has opened the door to new possibilities for catalysis. Her PhD research was undertaken in the Advanced Sustainable Processes by Engaging Catalytic Technologies (ASPECT) programme, which focuses on the catalysis of chemical processes in the bulk chemicals industry with the aim of increasing the sustainability of these processes. ASPECT is part of the NWO organisation ACTS (Advanced Chemical Technologies for Sustainability).
Source: NWO (Netherlands Organization for Scientific Research)