Photo: Joachim Rode

Georgeite can improve the production of methanol

Tuesday 09 Aug 16

Contact

Jakob Birkedal Wagner
Professor, Scientific director
DTU Cen
+45 45 25 64 71

Contact

Elisabetta Maria Fiordaliso
Researcher
DTU Cen
+45 45 25 64 66

Georgeite as catalyst material

Photo: Joachim Rode
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 and instability it has never been used in methanol synthesis. Now, a team of researchers from Cardiff University has found a method for producing georgeite in large quantities. And this has made it attractive to produce even better catalysts for methanol production.

The mineral georgeite is found only in a few places in the world. Researchers can now produce the synthetically.


Thick concrete slabs protecting microscopes

The largest of a total of eight electron microscopes at DTU Cen is the almost four-metre-high FEI Titanium Environmental Transmission Electron microscope. The microscope is one of the most powerful of its kind in the world and one of the few which can maintain a high resolution while particles are exposed to a gas atmosphere.

DTU Cen has a remote location at DTU because the microscopes are very sensitive. Therefore, they have been placed on metre-thick concrete slabs that rest on even thicker pads of gravel to protect against mechanical vibrations from the nearby motorway. As the electron microscopes are also disturbed by uneven temperatures, refrigeration pipes are integrated in the ceiling of the centre, which together with the ventilation ensures uniform temperatures throughout the room.


Researchers at DTU have helped an international team of researchers 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.

Using one of the world’s most powerful electron microscopes, researchers from DTU Cen—the DTU Center for Electron Nanoscopy—have demonstrated how the extremely rare mineral georgeite can help streamline methanol production. In February 2016, their findings were published in the scientific journal Nature.

The result means that the mineral can be used in catalysts which—in the long term—will make it possible to produce methanol more quickly, cheaply, and efficiently than previously. This could have a major impact on the production of methanol, which is one of the most important chemicals in the world and used in the production of plastic and synthetic fuel, for example.

“Using our electron microscope, we’ve been able to describe why the rare mineral georgeite is such good catalyst material, and why it makes a better catalyst than other substances,” says Elisabetta Maria Fiordaliso, Postdoc at DTU.

Unique microscope
Working with Professor Jakob Birkedal Wagner, Scientific Director at DTU Cen, Elisabetta was responsible for the basic research into the mineral. Last year, they were contacted by researchers from Cardiff University, who succeeded in producing the extremely rare and unstable mineral georgeite synthetically. The researchers compared the properties of georgeite as a catalyst with other commercial catalysts. But the Welsh researchers lacked further insight into precisely how georgeite could improve the catalyst for methanol production.

To examine the particles, DTU researchers used the almost four-metre-high FEI Titanium Environmental Transmission Electron Microscope, which is one of eight electron microscopes at DTU Cen used to characterize materials on everything from microscale to atomic scale.

The microscope is one out of just a handful in the world that can maintain a high resolution while the samples are exposed to a gas atmosphere.

Photo: Joachim Rode

Can ‘see’ the materials’ atomic structure
Electron microscopes enable, for example, examining the type of nanomaterials known as catalysts. 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, thus often also making them cheaper.

“The unique feature of this electron microscope is that we can use it to study the material in the environment in which the catalyst is to operate. In this way, we can ‘see’ the materials’ atomic structure, both on the surface and in depth, and examine their function,” says Jakob Birkedal Wagner.

“By heating mineral under a gas atmosphere in electron microscopes, we saw how the material changed from being a rare mineral to becoming an active catalyst. We then compared georgeite with the mineral malachite (which is currently used as a catalyst in global methanol production, ed.) and found out that georgeite has a finer microstructure with smaller copper particles. It gave us proof that georgeite is a better catalyst than other commercial catalysts.”

Electron microscopy
DTU Cen—Center for Electron Nanoscopy is financed by a donation from The A.P. Møller Foundation.


How the researchers have used the super microscope

Photo: Joachim RodeResearchers at DTU Cen have used one of the world’s most powerful electron microscopes to detect how the mineral georgeite can improve methanol production. In two areas it distinguishes itself from other electron microscopes.


Reaction chamber
A major advantage of the microscope is the so-called reaction chamber, where the researchers have been able to study the particles in the mineral georgeite in the environment in which the catalyst material has to function. Normally, an electron microscope only functions in a vacuum, but the FEI Titanium Environmental Transmission Electron Microscope features a reaction chamber where chemical reactions between gases and solids are examined under high pressures. This is possible because the finely focused electron beam is sent into the chamber through a very small hole, while powerful pumps maintain vacuum in the rest of the microscope. The technique allows the researchers to film physical and chemical reactions, as they happen.


Magnetic lenses
A standard electron microscope in a good quality has a solution of about 0.2 nanometres, and until a few years ago, it was impossible to improve the solution further. The reason for this was two-fold: There are always errors in the magnetic lenses that focus the electron beam, and there is always a degree of scattering in the electron beam energy and thus in their wavelengths. In the FEI Titanium Environmental Transmission Electron Microscope, the error in the magnetic lenses have been remedied by incorporating two rings with six magnets in each ring. This increases the solution from 0.2 to 0.07 nanometres.