Single-atom catalysts attract growing attention in heterogeneous catalysis, as they make it possible to reduce the amount of metal required—and therefore the overall cost—while also improving catalytic activity and/or selectivity. However, precisely characterizing the coordination environments of each isolated metal atom, their distribution, and how they evolve under catalytic conditions remains a major challenge. Researchers have now shown that solid-state 195Pt NMR spectroscopy can directly visualize the local environment of platinum atoms dispersed within a porous support. Even more, they were able to track how these environments evolve during catalytic reactions—crucial insights for boosting catalytic performance.
Metals play a central role in heterogeneous catalysis, enabling a wide variety of reactions. Dispersing them as isolated atoms on a support not only ensures optimal use of these precious elements but also significantly enhances catalyst reactivity and stability. This strategy opens the door to innovative approaches that could transform the field of heterogeneous catalysis.
Platinum is a prime example. It efficiently catalyzes numerous electro-, photo-, and thermo-catalytic reactions. Yet, because of its rarity and high cost, every atom must be used to its fullest potential, which means maximizing the active surface area accessible to reactants. In other words, the goal is to expose as many platinum atoms as possible.
To achieve this, researchers employ strategies such as synthesizing metal nanoparticles or depositing thin layers onto suitable supports. The ultimate step is dispersing platinum atom by atom within nanoporous materials, most often nitrogen-doped carbon (NC). However, these dispersed atoms can occupy different anchoring sites that are notoriously difficult to characterize. A precise understanding of their exceptional reactivity requires detailed knowledge of their coordination environments, distribution, and behavior under catalytic conditions.
This publication is the result of a collaboration between scientists at the Very High Field NMR Center in Lyon (CNRS/École Normale Supérieure de Lyon/Université Claude Bernard Lyon 1), and with a team from ETH Zürich with aknowledgement of PANACEA funding. They have demonstrated that solid-state ^195Pt NMR spectroscopy is particularly powerful for probing the coordination environment of platinum atoms dispersed on carbon supports. Their studies, carried out on various supports with platinum concentrations ranging from 15% to 1% by weight, revealed—through Monte Carlo simulations and density functional theory (DFT) calculations—the local environments of platinum centers (the number of nitrogen, carbon, or chlorine atoms surrounding Pt). They were also able to quantify the distribution of catalytic sites within the matrix and assess their homogeneity.
This methodology further enabled researchers to monitor, quantitatively, how the coordination environment evolved during catalytic reactions, as well as depending on the support material. In doing so, they highlighted surface effects on activity, offering new insights into reactivity differences and possible causes of catalyst deactivation.
By providing an unprecedented level of detail on the atomic-scale environment of metals, this approach paves the way for the rational design of next-generation atomically dispersed catalysts. It offers valuable structural benchmarks to optimize supports and stabilize well-defined metal sites.
The findings were recently published in Nature.
Find the full article here: https://www.nature.com/articles/s41586-025-09068-x.
