Single-Atom Catalysis for Oxygen Reduction Reactions

Single-atom catalysis introduces individual metal centres dispersed on conductive supports, maximising active site exposure and achieving near‐atom efficiency in oxygen reduction reactions (ORR). By isolating transition metal atoms—such as iron, cobalt or copper—within nitrogen‐doped carbon matrices, these catalysts exhibit unique electronic structures that can be tuned through local coordination, heteroatom doping or pore engineering. The precise control over metal–support interactions reduces undesirable side reactions and enhances selectivity, while the abundant use of non-precious metals addresses sustainability and cost challenges. Recent advances have focused on optimising coordination spheres, regulating d-electron density and inducing structural heterogeneity to accelerate O₂ adsorption, intermediate desorption and electron-transfer steps. These developments underpin applications in alkaline and acidic media, including fuel cells and metal–air batteries, and contribute to global efforts in clean energy conversion and storage.

Research from Nature Portfolio

Recent studies have demonstrated that hierarchically porous iron single-atom catalysts, with atomically dispersed Fe sites in both micropores and mesopores, exhibit enhanced ORR performance through long-range electron regulation between interacting sites. Structural heterogeneity has been shown to optimise the activation and desorption of oxygen intermediates, leading to higher turnover frequencies and robust half-wave potentials exceeding 0.94 V. In parallel, atomically dispersed cobalt-based catalysts anchored on nitrogen-doped graphene for quasi-solid-state zinc–air batteries have enabled high-rate capability and broad temperature adaptability. The tailored Co–N coordination and an advanced organohydrogel electrolyte facilitate stable cycling at current densities up to 100 mA cm⁻², highlighting the potential of single-atom electrocatalysts in practical energy devices.

Single-Atom Catalysis for Oxygen Reduction Reactions publication trend

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

Technical terms

Single-atom catalyst: A catalyst in which individual metal atoms are isolated and supported on a substrate to maximise atom utilisation and active site uniformity.

Oxygen reduction reaction (ORR): The electrochemical process in which O₂ is reduced to water or hydroxide, a key reaction in fuel cells and metal–air batteries.

Metal–nitrogen–carbon (M–N–C) catalyst: A class of non-precious electrocatalysts comprising single metal atoms coordinated by nitrogen within a carbon matrix.

Half-wave potential: The potential at which the current reaches half of its maximum value during an electrochemical sweep, indicating catalytic activity.

Density functional theory (DFT): A quantum mechanical modelling method used to investigate the electronic structure and predict reaction mechanisms of catalysts.

References

1. Mesopore‐Rich Fe–N–C Catalyst with FeN4–O–NC Single‐Atom Sites Delivers Remarkable Oxygen Reduction Reaction Performance in Alkaline Media. Advanced Materials (2022).
2. Inter-site structural heterogeneity induction of single atom Fe catalysts for robust oxygen reduction. Nature Communications (2024).
3. Quasi-solid-state Zn-air batteries with an atomically dispersed cobalt electrocatalyst and organohydrogel electrolyte. Nature Communications (2022).
4. High Durability of Fe–N–C Single‐Atom Catalysts with Carbon Vacancies toward the Oxygen Reduction Reaction in Alkaline Media. Advanced Materials (2023).
5. Co(O)4(N)‐type single‐atom‐based catalysts and ligand‐driven modulation of electrocatalytic properties for reducing oxygen molecules. EcoEnergy (2024).
6. Engineering d-band center of FeN4 moieties for efficient oxygen reduction reaction electrocatalysts. Energy Storage Materials (2023).