Stanford researchers have introduced a software tool that accelerates and enhances the analysis of single atom catalysts, offering profound implications for the development of more efficient catalysts.
Catalysts play an essential role in everyday life, from helping bread rise to converting raw materials into fuels more efficiently. Now, researchers at SLAC have developed a faster method to advance the discovery of an exciting new type of catalyst known as single atom catalysts.
The Role of Catalysts in Modern Chemistry
For decades, catalysts have quietly powered countless processes in everyday life. These essential substances reduce the energy needed to transform raw materials into useful products, much like yeast helps bread rise. From making fuels to driving sustainable chemical reactions, catalysts play a vital role.
Among them, a promising category known as single atom catalysts has gained attention. To fully harness their potential, researchers need better ways to study them—particularly the structures of their “active sites,” where chemical reactions occur. Understanding these sites is key to improving their ability to accelerate reactions, known as their activity.
Advancements in Single Atom Catalyst Research
In an important step forward, researchers from the Stanford Synchrotron Radiation Lightsource (SSRL) at the Department of Energy’s SLAC National Accelerator Laboratory collaborated with a team from the University of California, Davis (UC Davis), to develop a new software tool that can provide more quantitative details about the structure of the active sites in single atom catalysts in much less time, compared to current methods. The results were published in Chemistry–Methods.
Normally, a catalyst uses an inert support to stabilize nanometer-sized clusters of metal atoms, or metal nanoparticles. During catalysis, only the surface atoms act as active sites, leaving atoms in the interior of the nanoparticle unused. To maximize the utilization of each metal atom, researchers came up with a promising idea – single atom catalysts, where individual metal atoms are dispersed onto the support.
Innovations in Catalyst Analysis Techniques
In designing and developing these catalysts, researchers need to understand the structure of the active sites so they can relate it to the activity. To learn more about the structure, the team used single platinum atoms stabilized on a magnesium oxide support as a case study for similar single atom catalysts.
The study’s lead author Rachita Rana, who recently received her PhD from UC Davis, utilized a technique called extended X-ray absorption fine structure (EXAFS) spectroscopy, which reveals the average environment around the atom in the active site, such as the number and distance of neighboring atoms.
Traditionally, with EXAFS data, researchers evaluate tens to hundreds of candidate structures before selecting the best fit. Instead, Rana proposed automating the analysis process by combining theoretical calculations, called density functional theory, and EXAFS. The first version of the software, QuantEXAFS, determined the structure for one kind of atom, platinum atoms in this case.
Streamlining Data Analysis in Catalysis
In reality, catalysts usually have both single atoms and nanoparticles. Building upon QuantEXAFS, Rana expanded the capabilities of the code to determine the fractions of these two forms, giving more specific information about the structure.
“MS-QuantEXAFS not only helps identify the active sites, but also quantifies the percentage of a specific site and automates the entire data analysis process,” she said. “If you’re doing this manually, it typically could take you anywhere from a few days to months. With MS-QuantEXAFS, you could potentially do this analysis overnight on a local computer.”
The team would next like to prepare and release MS QuantEXAFS to the scientific community. “This tool has a lot to offer to catalysis researchers,” said Rana. Co-author and Distinguished Scientist at SSRL, Simon R. Bare, agrees, adding that they also plan to include it in training classes, especially for the next generation of students.
Reference: “Quantifying the Site Heterogeneities of Non-Uniform Catalysts Using QuantEXAFS” by Rachita Rana, Jiyun Hong, Adam S. Hoffman, Baraa Werghi, Simon R. Bare and Ambarish R. Kulkarni, 21 November 2024, Chemistry – Methods.
DOI: 10.1002/cmtd.202400020
The DOE Office of Science supported this research. SSRL is a DOE Office of Science user facility.
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