Single-Atom Catalysis in Oxidation Reactions

Single-atom catalysis has emerged as a frontier in heterogeneous catalysis, combining the maximisation of atomic efficiency with unparalleled selectivity and activity in oxidation processes. By anchoring individual metal atoms onto supports such as metal oxides or carbonaceous materials, researchers achieve uniform active sites free from ensemble effects. These isolated atoms often exhibit unique electronic structures, enabling lower activation energies for O₂ dissociation, enhanced oxygen vacancy formation and precise control over oxidation state. Applications span environmental remediation—such as CO oxidation—and fine chemical synthesis, including selective alcohol and hydrocarbon oxidation. Advances in synthesis protocols, from atom trapping to chemical vapour deposition, ensure high density and stability of single atoms under reaction conditions. Furthermore, state-of-the-art characterisation tools, including aberration-corrected electron microscopy and operando spectroscopy, have elucidated dynamic metal–support interactions, revealing the crucial role of support defects and charge transfer in modulating catalytic pathways. The global significance of this field lies in its potential for energy-efficient oxidation at lower temperatures, reduced precious metal loadings and highly selective transformations that minimise by-products and waste.

Research from Nature Portfolio

Recent studies have demonstrated that atomically dispersed palladium on ceria nanostructures achieves complete CO oxidation at temperatures as low as 100 °C. Detailed operando X-ray absorption experiments revealed that dynamic switching between Pd²⁺ and Pd⁰ states at oxygen vacancy sites is responsible for the exceptionally low activation barrier. In a separate report, iron single-atom catalysts supported on nitrogen-doped carbon achieved highly selective oxidation of styrene to benzaldehyde under ambient conditions. Spectroscopic investigation under reaction conditions showed that single Fe centres coordinate with both H₂O₂ and substrate, facilitating a radical-free oxidation pathway with turnover numbers exceeding 10,000. These findings underscore the importance of tailored support chemistry and real-time characterisation for optimising single-atom active sites in oxidation reactions.

Single-Atom Catalysis in Oxidation Reactions publication trend

The graph below shows the total number of articles in single-atom catalysis in oxidation reactions across all publications each year (not limited to Nature Index journals).

Technical terms

Single-Atom Catalyst: A heterogeneous catalyst in which individual metal atoms are dispersed on a support, offering discrete active sites with maximised atomic efficiency.

Metal–Support Interaction: The electronic and structural interplay between a metal atom and its support that governs charge transfer, bond formation and catalytic activity.

Oxygen Vacancy: A defect site in an oxide support where an oxygen atom is missing, often acting as an anchor for single metal atoms and facilitating oxygen activation.

Turnover Number (TON): The number of reactant molecules transformed per active metal site before deactivation, reflecting catalyst durability and efficiency.

Operando Spectroscopy: Characterisation techniques performed under actual reaction conditions to monitor the structure and oxidation state of active sites in real time.

References

1. An oxidized magnetic Au single atom on doped TiO 2 (110) becomes a high performance CO oxidation catalyst due to the charge effect. Journal of Materials Chemistry A (2017).
2. Substrate co-doping modulates electronic metal–support interactions and significantly enhances single-atom catalysis. Nanoscale (2016).