For groundbreaking work on single-atom catalysts, Charles Sykes and colleagues receive the Royal Society of Chemistry’s Horizon Prize
Charles Sykes, the John Wade Professor of chemistry, and his team at Tufts have received the 2022 Faraday Division Horizon Prize from the Royal Society of Chemistry (RSC) for their groundbreaking work on single-atom catalysts.
They join a prestigious list of winners in the RSC’s prize portfolio, some 50 of whom went on to win Nobel Prizes.
The single-atom catalyst research, which began more than 15 years ago, has the potential to transform the chemical industry, reducing the cost of chemical production, improving efficiency, and significantly reducing release of carbon dioxide and other unwanted by-products of the catalytic process.
The Tufts team, which originated the concept of dispersing single, isolated atoms on a catalytic metal surface, shared the prize with collaborators at University College London, the University of Cambridge, the University of California Santa Barbara, and Argonne National Library.
In addition to Sykes, other researchers at Tufts who received the prize are the late Maria Flytzani-Stephanopoulos, the Robert and Marcy Haber Endowed Professor in Energy Sustainability and Distinguished Professor; Prashant Deshlahra, assistant professor in the Department of Chemical and Biological Engineering; Georgios Giannakakis, EG21; Ryan Hannagan, AG21, and Yicheng Wang, AG23.
“This work could not have been done without everyone on the team contributing,” said Sykes. “The idea started in our lab, but its execution and its growth is a collaborative process, and now a global effort.”
Tufts Now recently spoke with Sykes about winning the Horizon Prize, and where the technology he spearheaded might be headed.
Tufts Now: The RSC award celebrates “the most exciting chemical science taking place today.” What is it about the single-atom catalyst technology that make is so significant?
Charles Sykes: Catalysts are the workhorses in the industrial production of most commodity and specialty chemicals. The market for catalysts themselves was $22 billion in 2020, and the value of chemicals made with the catalysts is over $3 trillion.
Almost every man-made product you touch, wear, and use has had some part of its production affected by catalysts.
But most catalytic reactions are inefficient to some degree, meaning that not all the starting material may end up as product, and much of it can end up as unwanted and sometimes harmful byproducts. Most notable among these is carbon dioxide, which as we know has become a huge problem contributing to climate change.
Catalysts in general, while integral to chemical production, are part of the inefficiency. Referred to as “heterogeneous catalysts,” they are composed of small metal particles which have many types of active sites on them, meaning that they not only catalyze the chemical reaction of interest but produce other unwanted chemicals. Making improved versions of these catalysts has always been an extensive trial and error process.
Our lab came up with the idea to simplify the catalytic active site. If we disperse the active metals—like palladium, platinum, or rhodium—to the extent that only single atoms are dispersed in the surface of copper or other chemically inert metal, we can begin to use computer modeling to predict chemical reactions and have the reactions proceed more efficiently and cleanly.
So the reactions are cleaner and more efficient, and better for the environment because they produce fewer harmful byproducts. Are there any other benefits?
The metals typically used for catalysts, like palladium or platinum, are very expensive and can be a few thousand dollars per ounce. When we atomically disperse them in inert metals like copper, which costs 15 cents per ounce, the catalysts are not only better, but much cheaper.
The contribution to sustainability is also very substantial. In the reaction to produce propene, typically one ton of carbon dioxide is released for every ton of propene produced. Our single-atom alloy catalyst can reduce this carbon emission almost down to zero.
With all these benefits, is industry starting to adopt the technology?
Yes, but it’s still in the early stages. What is more notable at this time is that the technology is being taken up by researchers across the globe. We have looked at publication trends and we are finding that studies employing single-atom alloy catalysts have grown exponentially in the last 10 years.
Our lab has applied the method to hydrogenation and dehydrogenation reactions, which encompasses a large sector of what industry does.
And there are groups all over the world that have taken up our approach and have shown single-atom alloy catalysts can facilitate at least 30 different kinds of reactions used by industry. In the commercial space, companies like BASF have shown an interest in using this approach.
How were your collaborators involved in helping you develop the technology?
The way our collaboration works is that we have theorists who model the reactions, and then we have my group, which does fundamental studies on surfaces, conducting imaging where we can see individual atoms and confirm the structure and composition of the model catalysts.
Our collaborators at University of California Santa Barbara have scaled-down versions of industrial reactors where they can test a few milligrams of catalyst to tell us whether it might work under industrial conditions.
Often a technology spreads widely when it is easy and inexpensive to adopt. Is that the case here?
For industry, it is relatively easy to make single-atom alloy catalysts using standard protocols. In an academic setting, though, it can be challenging to prove that you have made a single-atom catalyst, because that can require very advanced microscopy methods.
What difficulties lie ahead for the technology to get it widely adopted by the chemical industry?
A challenge moving forward is increasing the rate at which the single-atom catalysts make product.
While we can get 100% selectivity for production of chemicals like propene, which means all of the starting material ends up as product and we have no side products like carbon dioxide, our catalysts work optimally at 400°C.
Industry likes to produce propene at about 550°C to speed up production, but at that temperature our catalysts will deactivate. Our next goal will be to make these catalysts stable at higher temperatures so they can be adopted for large-scale chemical production.