‘Atomic Fingerprint’ of Catalyst Helps Industrial Researchers Refine Cleaner Oil

Researchers have made a major breakthrough in our understanding of a 2D material, molybdenum disulphide, a key ingredient used in industrial refinery catalysts. Understanding the structure of the material at the atomic level has led them to a new way to boost its efficiency. This could mean cheaper and more efficient catalysts for oil refineries in the near future, promoting a cleaner environment and helping industry to deal with increasingly stringent environmental legislation.

This research was carried out at the SuperSTEM National Facility at the Science and Technology Facilities Council’s (UK) Daresbury Laboratory in Cheshire and was led by Danish catalysis and technology company, Haldor Topsøe A/S, in collaboration with the Lawrence Berkeley National Laboratory (USA). It has now been published as the cover story in the prestigious chemistry journal, Angewandte Chemie.

Professor Quentin Ramasse, Scientific Director at SuperSTEM said: “What this research gives us is a deeper understanding into the atomic structure of molybdenum disulphide which could lead to significant improvements in the way industrial catalysts are fine-tuned in the near future, making them more efficient and cheaper to manufacture and upscale. This is chemistry at the single atom level working towards a new generation of catalysts for both a cleaner environment and positive economic benefits for industry.”

Gasoline, diesel and other fossil fuels contain small amounts of sulphur and nitrogen which are emitted into the atmosphere during fuel combustion. These elements are harmful to human health and the environment, and are a major source of acid rain.  Catalysts are required in oil refineries to reduce these harmful emissions.

2D material molybdenum disulphide (MoS2), which is only one atom thick, is the active ingredient found in catalysts used by oil refineries across the world.  As the world’s supply of crude oil is stretched, and low-sulphur crude oils become less available, demand for MoS2-based catalysts is increasing. But more efficient catalysts are urgently needed to keep up with this demand due to increasing global oil consumption and dirtier oil wells.

Now for the first time, this team of researchers has been able to study molybdenum disulphide in a way that it has never been seen before.  Using the SuperSTEM2 powerful electron microscope, one of only a handful of its kind in the world, they have been able to take the atomic fingerprint of molybdenum disulphide by imaging its each and every individual atoms, one by one. The images obtained disclose detailed knowledge about its structure at the atomic level, particularly around its elusive edges where, the team has discovered, the catalytic reaction can be made more powerful by the addition of single cobalt atoms.  This capability provides a deeper understanding as to where impurities may lie, or where additives, such as cobalt, could be most effectively introduced to significantly boost the efficiency of catalysts.

Dr Stig Helveg, co-author and senior research scientist at Topsoe, said: “These first-ever images show exactly how the individual atoms in the catalysts are arranged.  

Knowing this helps to explain what makes a catalyst good or bad. Such images are very difficult to obtain and we are working right at the edge of what is physically possible, simply because we need to distinguish each and every atom within the tiny crystallites of molybdenum, which are just a millionth of a millimeter in diameter.”

SuperSTEM is funded by the Engineering and Physical Sciences Research Council (EPSRC) and sits within the Sci-Tech Daresbury national science and innovation campus near Warrington, Cheshire.