Electrocatalytic Water Splitting Using Prussian Blue Analogues

Electrocatalytic water splitting offers a sustainable route to green hydrogen by driving the oxygen evolution reaction (OER) at the anode and the hydrogen evolution reaction (HER) at the cathode. Prussian blue analogues (PBAs) have emerged as versatile precatalysts for both half-reactions owing to their open-framework structures, abundant and tunable metal sites, and facile chemical modification. The cyanide-bridged lattice of PBAs permits controlled introduction of defects, heteroatoms or secondary phases to enhance electronic conductivity and catalytic activity. Strategies such as vacancy engineering, core–shell assembly, heterostructure fabrication and post-synthetic transformation into metal oxides, phosphides or sulfides have led to materials exhibiting low overpotentials, small Tafel slopes and extended stability in alkaline media. PBAs can be processed into hollow or mesoporous architectures to maximise active surface area and accelerate mass transport. Their modular synthesis enables pairing of optimised OER and HER catalysts in two-electrode electrolyser configurations, driving current densities above 10 mA cm⁻² at cell voltages below 1.6 V. These developments underline the global potential of PBAs to advance efficient, cost-effective water splitting for decarbonised energy systems.

Research from Nature Portfolio

Ionised-nitrogen plasma treatment has been employed to introduce unconventional carbon–nitrogen vacancies into nickel-iron PBAs, suppressing iron leaching during OER and forming an in situ oxy(hydroxide) active layer. The vacancy-mediated catalyst exhibits a markedly reduced overpotential for OER in alkaline media and improved long-term durability, demonstrating defect engineering as a powerful route to tune intrinsic activity. Separately, solvothermal synthesis of hollow Co–Fe and Ni–Fe PBA cages with open frameworks has yielded dual-function electrocatalysts for water and urea oxidation. The hollow architectures expose a high density of active sites, lowering overpotentials for oxygen evolution and accelerating reaction kinetics compared to their solid counterparts, while maintaining robust performance over extended operation.

Electrocatalytic Water Splitting Using Prussian Blue Analogues publication trend

The graph below shows the total number of articles in electrocatalytic water splitting using prussian blue analogues across all publications each year (not limited to Nature Index journals).

Technical terms

Prussian Blue Analogues: Cyanide-bridged coordination polymers composed of two transition metal centres, notable for open frameworks and tunable composition.

Electrocatalytic Water Splitting: Electrochemical process that uses catalysts to decompose water into oxygen and hydrogen gas under applied potential.

Oxygen Evolution Reaction (OER): Anodic half-reaction in water splitting involving four-electron transfer to generate O₂, often the rate-limiting step.

Hydrogen Evolution Reaction (HER): Cathodic half-reaction in water splitting where protons combine with electrons to form H₂ gas.

Overpotential: Additional potential beyond the thermodynamic requirement needed to drive an electrochemical reaction at a given rate.

Tafel Slope: Parameter derived from the Tafel equation that reflects the kinetics of an electrocatalytic reaction and charge-transfer characteristics.

References

1. Enhancing Oxygen Evolution Reaction Performance in Prussian Blue Analogues: Triple‐Play of Metal Exsolution, Hollow Interiors, and Anionic Regulation. Advanced Materials (2023).
2. Moderate heat treatment of CoFe Prussian blue analogues for enhanced oxygen evolution reaction performance. Journal of Energy Chemistry (2023).
3. Heterostructured Core–Shell Ni–Co@Fe–Co Nanoboxes of Prussian Blue Analogues for Efficient Electrocatalytic Hydrogen Evolution from Alkaline Seawater. ACS Catalysis (2023).
4. Unconventional CN vacancies suppress iron-leaching in Prussian blue analogue pre-catalyst for boosted oxygen evolution catalysis. Nature Communications (2019).
5. Boosting the activity of Prussian-blue analogue as efficient electrocatalyst for water and urea oxidation. Scientific Reports (2019).