Foto: Joachim Rode

Super microscope untying scientific knot

Tuesday 16 Feb 16

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Jakob Birkedal Wagner
Professor
DTU Nanolab
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Nature: 'Stable amorphous georgeite as a precursor to a high-activity catalyst'

DTU Cen has helped international researchers to prove how the mineral georgeite can improve the production of methanol. In the long term, the discovery will make it cheaper to produce methanol—one of the most important chemicals in the world. The research findings have just been published in Nature

Thanks to one of the world's most powerful electron microscopes, researchers from DTU Cen—the DTU Center for Electron Nanoscopy—have now demonstrated how the rare mineral georgeite can help to streamline the production of methanol. The findings have just been published in the scientific journal Nature.

The basic research has been conducted by Postdoc Elisabetta Maria Fiordaliso and Scientific Director and Professor Jakob Birkedal Wagner. Through their network, they were contacted by Cardiff University which needed further insight into how to improve the catalyst for methanol production by means of the special mineral georgeite.

In the long term, the mineral can help to produce methanol faster, cheaper, and more efficiently. It will have a major impact on the production of methanol, which, among other things, is used to produce plastic and synthetic fuel, and which is one of the most important chemicals in the world.

“Initially, it sounded like a simple task. Our task was to describe why georgeite is a good catalyst material and to document why it works better as a catalyst than other materials. However, it turned out to be a difficult task. When we examined the material in the microscope, the nanostructure (the particles) were difficult to distinguish from each other. We therefore had to use different methods to characterize the relevant nanoparticles and compare them with each other,” says Elisabetta Maria Fiordaliso.

Unique electron microscope
She works at the Center for Electron Nanoscopy, which, among other things, specializes in the visualization of nano-objects. Funded by a donation from the A.P. Møller Foundation, the centre houses eight electron microscopes, which are used to characterize materials on everything from atomic-scale to microscale.

To examine the particles, the researchers used the almost four metres tall FEI TITAN Environmental Transmission Electron Microscope. The electron microscope has a resolution of 0.08 nm, making it possible to see atoms. The microscope is one out of ten or so in the world that can maintain a high resolution while the samples are exposed to a gas atmosphere. Here, the researchers can study dynamic interactions between gases and solid substances at high temperatures. This allows them to ‘see’ the materials’ atomic structure, both on the surface and in depth, and to examine their function.

“It's quite unique that this electron microscope can be used to study the material in the environment in which the catalyst is to operate. Such studies normally take place in a vacuum," says Jakob Birkedal Wagner.

“Furthermore, we are good at linking structure and functionality. In this case we have linked the catalytic reaction and the structure at atomic scale. Our extensive experience within electron microscopy and catalysts has thus made it possible for us to get an understanding of the problem in collaboration with international colleagues in a relatively short period of time.”

Georgeite as catalyst material

Copper-zinc based minerals, such as malachite, aurichalcite, and rosasite, have been used as starting material for effective catalysts for methanol production for 50-70 years. Georgeite is also a copper-zinc based mineral, but due to its rarity it has never been used in methanol synthesis. A method has now been found to produce georgeite in large quantities. And this has made it attractive to produce even better catalysts for methanol production.

An electron microscope is a useful instrument for studying the type of nanomaterials which are called catalysts, as they typically consist of nanoparticles, where the atomic structure determines the catalyst’s properties. A catalyst is a material which brings about a chemical reaction. The catalysts are special in that they accelerate chemical reactions with less energy consumption and often also making them cheaper.