Electrocatalytic Activity in Oxygen Reduction Systems

Electrocatalytic oxygen reduction is the process by which molecular oxygen is reduced to water or hydroxide at the cathode of fuel cells, metal–air batteries and related energy conversion devices. The reaction is intrinsically sluggish, owing to the transfer of four electrons and multiple proton-coupled steps. State-of-the-art catalysts seek to optimise adsorption energies of key intermediates, reduce overpotential and enhance durability under operating conditions. Strategies encompass noble metals, often platinum or palladium, supported on high-surface-area carbons, transition metal–nitrogen–carbon (M–N–C) complexes and doped oxide materials. Recent advances utilise atomic-scale engineering, defect and strain modulation, and bifunctional materials that bridge oxygen reduction with hydrogen evolution. Global efforts target cost reduction through non-precious alternatives, while maintaining performance and stability in both acidic and alkaline media. Progress in understanding structure–activity relationships, synthesising nanostructured networks and deploying in device architectures has accelerated practical applications of ORR electrocatalysts.

Research from Nature Portfolio

Recent studies have demonstrated that atomically dispersed platinum species anchored on nitrogen-doped carbon frameworks yield remarkable oxygen reduction activity and durability under alkaline conditions. Spectroscopic analyses reveal strong metal–support interactions that modulate the Pt d-band centre, lowering overpotential and suppressing sintering during long-term operation. Concurrently, defect engineering in perovskite oxide catalysts has emerged as a powerful route to tune electronic structure and oxygen adsorption kinetics. By introducing oxygen vacancies into LaFeO₃-based materials, researchers have achieved significantly enhanced four-electron pathways and reduced kinetic barriers in polymer electrolyte fuel cells. Further, metal–nitrogen–carbon catalysts derived from metal–organic frameworks have delivered bifunctional performance suitable for rechargeable zinc–air systems. These materials combine high active-site density with hierarchical porosity, striking a balance between mass transport and catalytic turnover, thereby bridging the gap between high activity and operational stability.

Electrocatalytic Activity in Oxygen Reduction Systems publication trend

The graph below shows the total number of articles in electrocatalytic activity in oxygen reduction systems across all publications each year (not limited to Nature Index journals).

Technical terms

Electrocatalyst: A material that accelerates electrochemical reactions by lowering activation energy and facilitating electron transfer at electrode surfaces.

Oxygen Reduction Reaction (ORR): The electrochemical process in which O₂ molecules accept electrons and protons to form water or hydroxide, central to fuel cells and metal–air batteries.

Overpotential: The extra potential required beyond the thermodynamic equilibrium voltage to drive an electrochemical reaction at a specified rate.

Mass activity: The catalytic current generated per unit mass of active material, reflecting the efficiency of catalyst utilisation.

Vacancy defect: A missing atom in a crystal lattice that alters electronic structure and can enhance adsorption and reactivity of electrocatalysts.

References

1. Tuning the Structure of Pd@Ni–Co Nanowires and Their Electrochemical Properties. The Journal of Physical Chemistry Letters (2024).
2. One-Pot Synthesis of Pd Nanoparticles Supported on Carbide-Derived Carbon for Oxygen Reduction Reaction. Nanomaterials (2024).
3. Oxygen Reduction Reaction and Hydrogen Evolution Reaction Catalyzed by Pd–Ru Nanoparticles Encapsulated in Porous Carbon Nanosheets. Catalysts (2018).
4. A Facile Method to Prepare Ultrafine Pd Nanoparticles Embedded into N-Doped Porous Carbon Nanosheets as Highly Efficient Electrocatalysts for Oxygen Reduction Reaction. Journal of The Electrochemical Society (2020).