Another step towards greenhouse gas recycling – University of Innsbruck
Using dry reforming, the greenhouse gases methane and carbon dioxide could be converted into useful synthesis gas. Researchers led by Bernhard Klötzer from the Institute for Physical Chemistry at the University of Innsbruck have been researching this catalytic process for some time and have now been able to answer important questions for process optimization. They published the results in the journal Angewandte Chemie.
Methane, one of the most harmful greenhouse gases, which is mainly released in the production of natural gas but also in numerous digestion and fermentation processes, is already being used to produce synthesis gas. This serves as the basis for synthetic fuels, for example. “In the course of dry reforming, carbon dioxide – the best-known greenhouse gas – is also used to produce synthesis gas together with methane,” explains assoz. Prof. Dr. Bernhard Klötzer from the Institute for Physical Chemistry at the University of Innsbruck. He researches his Working group Nanostructured Model Catalysts including the process of dry reforming. The problem here is observing this high-temperature catalysis process in situ, i.e. during the ongoing reaction.
in situ observation
For the first time, the scientists succeeded in proving a previously unknown reaction intermediate stage of dry reforming under model conditions and thus obtained important clues for process optimization. In the work published in the journal Angewandte Chemie, the working group led by Bernhard Klötzer, in collaboration with researchers at the TU Berlin and the Lawrence Berkeley National Laboratory, was able to show that graphitic carbon deposits on nickel are converted into a zirconium carbide interface phase during catalysis. These turned out to be a very reactive intermediate in this dry reforming. “This intermediate stage can only be detected in situ. However, the information from this model experiment is of great importance for the optimization of the transformation process, since non-reactive carbon leads to coking of the catalyst relatively quickly, which makes industrial use inefficient,” explains Bernhard Klötzer. Tests at the new high-pressure X-ray photon spectrometer in Innsbruck and at the Advanced Light Source (ALS) in Berkeley have shown that undissolved carbon reacts much more slowly, leading to sustained coking of the catalyst. “To prevent this, the process must be controlled in such a way that the unreactive carbon is converted into reactive carbon as efficiently as possible,” explains Klötzer. This conversion is enhanced by an optimized catalyst interface between the support and the nickel metal. “The tests on the model have shown that nickel is very well suited to increasing this desired reactivity of the carbon,” explains Klötzer, emphasizing that these results are a further step towards the industrial use of dry reforming for the recycling process of methane and to advance carbon dioxide substantially.