Single Atom Catalysts Maximize Efficiency and Minimize Waste

By Ankit SinghReviewed by Frances BriggsSep 24 2025

Single-atom catalysts promise cleaner chemistry. Squeezing the maximum value from every atom, cutting waste, and reshaping how industries tackle energy, emissions, and sustainable production. 

 Artistic rendering of an atom in 3D. Image Credit: Dabarti CGI/Shutterstock.com

Fundamentals of Single-Atom Catalysis

Traditional catalysts often waste material because only surface atoms participate in reactions, while the bulk material goes untouched. Single-atom catalysts (SACs) overcome this inefficiency by dispersing individual metal atoms across supports, ensuring that every atom is active.

Their ability to control the chemical environment of each atom with precision drives their selectivity and activity in specific reactions. The supports, ranging from nitrogen-doped carbons to engineered oxides, stabilize single atoms through tailored coordination, creating predictable and reproducible active sites.¹

Recent advances in high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and X-ray absorption spectroscopy have allowed researchers to confirm atom dispersion and probe the relationship between structure and activity.

The latest studies also emphasize the challenge of reliably assessing local bonding environments and maintaining synthetic reproducibility, both of which are necessary for scaling industrial production of SACs.¹

Maximizing Efficiency: Atom Utilization and Reaction Pathways

Because every atom in an SAC is catalytically available, these catalysts are remarkably efficient. Platinum-based SACs, for example, have shown exceptional activity and stability in carbon monoxide (CO) oxidation, optimizing electronic structure at the atomic scale, which lowers energy barriers and improves conversion rates. Similar principles extend across various metals and different supports, providing consistent advantages in reaction rates and atom use for key industrial processes.¹

Their efficiency can be further enhanced through tandem catalysis, in which multiple reaction steps occur seamlessly within a single reactor. Combining ruthenium and rhodium atoms on a ceria support, for example, enables olefin isomerization followed by hydrosilylation, producing organosilane compounds with regioselectivity greater than 95 %. Such designs accelerate reaction times and reduce the need for intermediate isolation, saving energy and minimizing material waste.²

Catalyst Architecture and Support Selection

The performance of SACs depends not just on atom dispersion, but also on the support properties of the material. Ceramic supports such as cordierite and mullite provide strength and resistance to heat and corrosion, making them suitable for high-temperature environments. Metal supports can accelerate electron transfer with their high conductivity, a property critical to electrocatalytic reactions.

Carbon and graphene, valued for their high surface areas and tunable electronic structures, stabilize single atoms and extend catalyst lifetime. Aerogels offer efficient mass transport with their lightness and porosity, but can be mechanically fragile.¹

Choosing the right support requires aligning its thermochemical, mechanical, and electronic properties to the reaction in question. High porosity can be advantageous for processes reliant on rapid diffusion of reactants, for example, while conductive metals are vital for electrocatalytic reductions such as hydrogen evolution or CO₂ conversion.¹

Minimizing Waste: Selectivity and Green Chemistry

One of the defining characteristics of SACs is their ability to reduce byproducts by offering superior selectivity. Carefully engineered single-atom sites enable sequential or complementary reactions within a single system.

In one case, rhodium atoms were used to generate hydrogen that converted nitroarenes to anilines via a hydrogenation reaction, achieving yields of over 99 %. This level of control can simplify purification and cut energy use, helping scientists to conduct research aligning with the 12 principles of green chemistry.^2,3

Auxiliary supports can further influence outcomes. For example, integrating acid or oxygen vacancy sites into supporting materials can result in synergistic outcomes, enabling reactions like hydrogenolysis of biomass-derived compounds with greater efficiency. The proximity and density of such single atoms and support sites impact mass transfer of intermediates, and recent research has investigated how to tune these distances to improve performance without raising complexity or cost.³

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Applications Across Industries

SACs are versatile, and it's this versatility that has led to their application across automotive, energy, environmental, and chemical sectors. In exhaust treatment, they convert carbon monoxide and nitrogen oxides into benign substances via gas purification methods.

Water treatment operations employ SACs for the breakdown of organic pollutants and heavy metals, with precise site control maximizing conversion while resisting catalyst poisoning. In the fuel cell and renewable energy sector, SACs are being used to promote electrocatalytic reduction of carbon dioxide and hydrogen production, improving efficiency and selectivity under varying operating conditions.^1,3,4,5

In industrial synthesis, SACs can support key reactions like coupling or oxidation. Tandem catalysts can combine hydrosilylation, epoxidation, and C-C coupling reactions, for instance, to create advanced polymer or pharmaceutical precursors with minimal waste and maximum atom economy.

Recent advances include using MXene-supported SACs for various electrochemical reactions and using compartmentalization strategies to further enhance relay-mode tandem processes.^3,5

Challenges and Outlook

There are several pitfalls that prevent SACs from being widely adopted, despite their success. The use of precious metals, like platinum and palladium, is expensive and these metals are generally in limited supply. Efforts are being made to find cheaper substitutes without compromising performance.

Another dilemma is catalytic stability during long-term operation. For these catalysts to be suitable in industrial conditions for extended periods of time, and at scale, improving characterization methods and tools to capture the spatial arrangement of single atoms will be necessary.^6,7

Scalable manufacturing and use also depend on standardized protocols, testing, and real-world evaluation of SAC-enabled processes. Interdisciplinary collaboration among chemists, engineers, and data scientists is important for such innovations in catalyst design and application.^6,7

Conclusion

Single-atom catalysts are a remarkable innovation in catalysis that could provide a way to meet green principles with their resource efficiency and low waste. By combining atomic-level design with well-chosen supports, SACs achieve higher activity, selectivity, and stability than many traditional alternatives. Continued innovation in synthesis, characterization, and digital catalyst engineering will further enhance the properties of SACs for more sustainable industrial chemistry.

References and Further Reading

1. Luo, J. et al. (2025). Structured, Shaped, or Printed Single-Atom Catalysts and Their Applications. Advanced Functional Materials, 35(34), 2424514. DOI:10.1002/adfm.202424514. https://advanced.onlinelibrary.wiley.com/doi/10.1002/adfm.202424514
2. Sarma, B. B. et al. (2020). One-Pot Cooperation of Single-Atom Rh and Ru Solid Catalysts for a Selective Tandem Olefin Isomerization-Hydrosilylation Process. Angewandte Chemie International Edition, 59(14), 5806-5815. DOI:10.1002/anie.201915255. https://onlinelibrary.wiley.com/doi/10.1002/anie.201915255
3. Liu, C., Qiao, B., & Zhang, T. (2024). Integration of Single Atoms for Tandem Catalysis. JACS Au. DOI:10.1021/jacsau.4c00784. https://pubs.acs.org/doi/10.1021/jacsau.4c00784
4. Zhao, W. et al. (2025). Design Principles of Single-Atom Catalysts for Electrocatalytic CO2 Reduction to High-Value Hydrocarbons. Chemistry – An Asian Journal, e00545. DOI:10.1002/asia.202500545. https://aces.onlinelibrary.wiley.com/doi/10.1002/asia.202500545
5. He, J. et al. (2025). MXene-Supported Single-Atom Electrocatalysts. Advanced Science, 12(17), 2414674. DOI:10.1002/advs.202414674. https://advanced.onlinelibrary.wiley.com/doi/10.1002/advs.202414674
6. Yu, Q. et al. (2025). AI in single-atom catalysts: a review of design and applications. Journal of Materials Informatics, 5(1). DOI:10.20517/jmi.2024.78. https://www.oaepublish.com/articles/jmi.2024.78
7. Liu, Y. et al. (2024). Progress and challenges in structural, in situ and operando characterization of single-atom catalysts by X-ray based synchrotron radiation techniques. Chemical Society Reviews. DOI:10.1039/d3cs00967j. https://pubs.rsc.org/en/content/articlelanding/2024/cs/d3cs00967j

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