The Researchers at ETH Zurich have used nuclear magnetic resonance (NMR) to investigate the atomic surroundings. They have also done it for the spatial orientation of individual platinum atoms embedded in solid supports. This technique is reliable for improving the design and production of single-atom catalysts in the future.

Catalysis is the process of accelerating chemical reactions by introducing a specific substance called a catalyst. They are vital to both industry and everyday life. Approximately 80% of all chemical products tend to depend upon catalytic processes. The technologies, such as exhaust treatment systems and fuel cells, are also based on this principle. Platinum stands out as a particularly efficient and versatile catalyst. However, as it is rare, high cost, and the significant CO₂ emissions associated with its extraction, it’s crucial to minimize the usage of platinum while enhancing its catalytic performance.

Single Atom Catalysts

Recently, scientists have been working to develop single-atom catalysts, i.e. materials in which each atom directly participates in a chemical reaction. These catalysts are created by placing isolated platinum atoms onto the surface of a porous support, such as nitrogen-doped carbon. The nitrogen atoms serve as anchoring points. This further helps to stabilize the platinum atoms in place.

A research team led by Javier Pérez-Ramírez and Christophe Copéret from the Department of Chemistry and Applied Life Sciences at ETH Zurich, alongside collaborators from the Universities of Lyon and Aarhus, has shown that these catalysts are more intricate than previously understood. 

A Closer Look at Catalyst Complexity

By using nuclear magnetic resonance (NMR), the researchers discovered that single platinum atoms can exist in a range of atomic environments. For each of which influences their catalytic behavior differently. This insight could pave the way for the design of more efficient catalytic materials. The team’s findings were recently published in the scientific general Nature.

Until now, individual platinum atoms could only be visualized using electron microscopy, which produces striking images but reveals little about how the atoms function as catalysts, explains Pérez-Ramírez. Motivated to learn more, he and Copéret began exploring new ways to characterize these atoms in greater detail, which led to a collaboration sparked by a serendipitous meeting at an NCCR Catalysis program event.

Decoding Platinum’s Magnetic Signals

Following that encounter, the team decided to apply NMR spectroscopy. It’s a method commonly used in labs to study molecular structures and is also known for its application in medical MRI. In NMR, atomic nuclei are placed in a strong magnetic field. They are further exposed to oscillating magnetic fields. The resonant frequencies at which these nuclei respond rely on the atoms surrounding them.

“Likewise, the resonant frequencies of the single platinum atoms are influenced by their atomic neighbours – for instance, carbon, nitrogen or oxygen – and their orientation relative to the static magnetic field”, Copéret explains.

This generates a wide range of signals, similar to the variety of notes in an orchestra. Determining which “instrument” (or atomic configuration) corresponds to which signal is a complex task.  “As luck would have it, during a visit to Lyon, one of us met a simulation expert from Aarhus who was visiting there at the same time”, says Copéret. That chance meeting led to a collaboration in which a specialized computer code was developed to disentangle the complex spectral signals and identify the specific environments of each platinum atom.

A Molecular-Level Map for Better Catalysts

This breakthrough allowed the researchers to create a detailed “map” of the atoms surrounding each platinum site. These essentially pinpoint their types and positions. “This analytical method sets a new benchmark in the field”, says Pérez-Ramírez.

As this technique is widely accessible, it opens the door to optimizing production methods for single-atom catalysts. Thus, all platinum atoms are placed in precisely tailored environments. “Our method is also important from an intellectual property standpoint”, says Copéret: “Being able to precisely describe catalysts at the atomic level enables us to protect them through patents.”

Original Publication
Authors: Jonas Koppe, Alexander V. Yakimov, Domenico Gioffrè, Marc-Eduard Usteri, Thomas Vosegaard, Guido Pintacuda, Anne Lesage, Andrew J. Pell, Sharon Mitchell, Javier Pérez-Ramírez and Christophe Copéret.
Journal: Nature
DOI: 10.1038/s41586-025-09068-x
Article Title: Coordination environments of Pt single-atom catalysts from NMR signatures
Article Publication Date: 4-Jun-2025

Original Source: https://ethz.ch/en/news-and-events/eth-news/news/2025/07/eine-landkarte-fuer-einzelatom-katalysatoren.html