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March 5, 2025
A Northwestern University-led international team of scientists has, for the first time, directly observed catalysis in-action at the atomic level.
In mesmerizing new videos, single atoms move and shake during a chemical reaction that removes hydrogen atoms from an alcohol molecule. By viewing the process in real time, the researchers discovered several short-lived intermediate molecules involved in the reaction as well as a previously hidden reaction pathway.
The observations were made possible by single-molecule atomic-resolution time-resolved electron microscopy (SMART-EM), a powerful instrument that enables researchers to watch individual molecules react in real time.
Observing reactions in this manner helps scientists understand how catalysts work. These new insights could potentially lead to designs for more efficient and sustainable chemical processes.
The study was published in the journal Chem.
“By visualizing this process and following the reaction mechanisms, we can understand exactly what’s happening in the finest detail,” said Northwestern’s Yosi Kratish, the study’s first and co-corresponding author. “In the past, we haven’t been able to see how atoms move. Now we can. When I realized what we accomplished, I had to close my laptop and take a break for a few hours. Nobody has done this before in catalysis, so I was stunned.”
“Catalysts make modern life possible,” said Northwestern’s Tobin J. Marks, the study’s senior author. “They are used to make everything from fuel and fertilizers to plastics and medicines. To make chemical processes more efficient and environmentally friendly, we need to understand exactly how catalysts work at the atomic level. Our study is a big step toward achieving that.”
A world-renowned expert in catalysis, Marks is the Charles E. and Emma H. Morrison Professor of Chemistry and Vladimir N. Ipatieff Professor of Catalytic Chemistry at Northwestern’s Weinberg College of Arts and Sciences and a professor of chemical and biological engineering at Northwestern’s McCormick School of Engineering. Kratish is a research assistant professor of chemistry in Marks’ group. Marks and Kratish co-led the study with Michael Bedzyk, professor of materials science and engineering at McCormick, and George C. Schatz, the Charles E. and Emma H. Morrison Professor of Chemistry at Weinberg, as well as the University of Tokyo’s Professor Eiichi Nakamura, who invented SMART-EM, and Assistant Professor Takayki Nakamuro.
Catching fleeting molecules with ‘cinematic chemistry’
Researchers long have sought to observe live catalytic events at the atomic level. Chemical reactions are like a journey between starting materials and the final product. Along the journey, transient — and sometimes unexpected — molecules form and then abruptly transform into other molecules. Because these so-called “intermediate” molecules are unpredictable and fleeting, they are difficult to detect.
By directly watching the reaction unfold, however, scientists can determine the exact sequence of events to reveal the complete reaction pathway — and view those elusive intermediates. But, until recently, it was impossible to observe these covert dynamics. While traditional electron microscopes can image atoms, their beams are too strong to image the soft, organic matter used in catalysis. The high-energy electrons easily break down carbon-based structures, destroying them before scientists can gather the data.
