New "designer molecule" can make the industry save big amounts
Researchers from Yale University in the United States have for a long time been investigating catalysts, which are an extremely important part of many chemical processes, for instance in the pharmaceutical industry. The most expensive and best catalysts can cost up to $ 2,000 per kg, while the cheapest is down to 12 $ per kg. As with everything else, there is a correlation between price and quality, but there is a lot to gain from making the bad ones a bit better, or to make the expensive a little cheaper.
The Yale researchers had so far studied how to make the chemical reaction more efficient, but now they wanted to try something new: Is it possible to change the durability of the catalysts and thus make them cheaper in operation?
Why are they broken?
The question the researchers had asked themselves,was not easy to answer, because it turned out to be rather difficult to measure exactly what happened during the reaction. To find the answer, they contacted David Balcells and Ainara Nova, both of whom are researchers at the Hylleraas Centre at the Department of Chemistry, University of Oslo. Balcells and Nova are experts in theoretical chemistry, and they made a model for what happens throughout the process. In this way, they found out how the catalyst was gradually "broken" down:
– We see that the catalyst evolves to form different species. One of these species binds to another one and contributes to deactivate the catalyst for the wanted reaction, and then it no longer contributes to the process. It is "broken". By modifying the part of the catalyst that facilitates the binding, we can prevent catalytic species reacting with each other so that they last longer and become more effective, Balcells explains.
He says that the catalysts' sole job is to make the reaction occur, and it is possible to imagine that they would last forever, in theory. Balcells and Nova's research shows that the life of a catalyst can be extended a lot by studying what they call off-cycle, that is, what puts the catalyst out of play. It turns out that there are more people that have gotten their eyes up for studying this part of the process:
– We can say that studying the off-cycle part of the process is about to become a trend, says Balcells.
Allround design for eternal life?
The scientific article was published in April. Nevertheless, researchers have been told that the catalyst they have designed works and has already been used by other researchers.
– We know it works because other researchers have already tested it for use in their experiments, says Balcells. The catalyst has already been tested in selective synthesis of different products, and it works.
These type of catalysts are used in many processes because they help carbon atoms bind to each other. In the pharmaceutical industry, they are used to produce medicines against, for example, hepatitis, obesity and respiratory diseases. These catalysts are also used to make thin film transistors for everything from LCD monitors to LED lights. The inventor (or the designer) of the original catalyst for this reaction received the Nobel Prize for his work in 2010.
The theoretically designed improvement of the catalyst has turned out to be good news for the researchers:
– When we have models we can count on, we've really got a powerful tool, Nova says.
But it does not stop there: The researchers have gotten more ideas about how the catalysts can be improved:
– Now we have made a catalyst become more active and robust, but maybe we can make it faster or last forever? ask Balcells.
Getting rid of poisonous expensive metals
Balcells and Nova have barely started investigating catalysts: Now they have moved on to another type of catalyst with a different element as a starting point. Many of the best catalysts can be both poisonous and expensive. Therefore, many choose to replace the most expensive ones with catalysts containing nickel, copper, or iron, which are cheaper and less toxic, but they are more quickly "destroyed". The researchers have begun to improve these and will work on this further:
– Nickel is still challenging, Nova comments.
The researchers are still collaborating with the Yale Group, currently receiving PhD students from Yale as an exchange. The PhD students receive a thorough introduction to both experimental and theoretical methods, and this has many advantages, according to Balcells:
– They are the ones who do the experiments, so they know what to look for in the model, he explains. The models help them to understand the experiments at the molecular level.
Will transform CO2 to methanol
Nova and Balcells make sure that the catalysts they design can be used in a wide range of tasks.
– What we have done now is an approach we can transfer to other systems. One example is CO2 reduction or extracting hydrogen from water, something that is necessary if we for example are to use hydrogen as a fuel, Nova explains. If we can reduce CO2 to methanol, we can do quite a bit with it.
Methanol is much easier to handle than CO2, partly because it is a liquid instead of a gas. Methanol has also several applications and can be used as fuel. Nova participates in a Nordic consortium that looks at carbon capture and use. This research is also relevant in the field of artificial photosynthesis.
Yes please, more cooperation!
It is not always possible to do research on what is exactly most desired, but the researchers at the Hylleraas Center emphasize curiosity as the main motivational factor.
– If you got funding to do research on what you wanted, what should it be?
– We're doing it already!
Although researchers emphasize that they are working on basic research, they want others to take the knowledge into use.
– One of our strengths is to develop the theories and the essence of science, but the natural step forward is to take this onto practical applications. If there is someone out there who needs help modeling processes to understand what's happening, we'd love to cooperate with them, says Balcells.
The research article:
Designing Pd and Ni Catalysts for Cross-Coupling Reactions by Minimizing Off-Cycle Species, David Balcells and Ainara Nova, ACS Catalysis, 2018,8, 3499. DOI: 10.1021/acscatal.8b00230
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