Spin-Dominated Reconstruction Kinetics in Prussian Blue Analog Enables Efficient Seawater Splitting

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• The spin state of metal centers critically influences the electrochemical reconstruction kinetics of Prussian blue analogs (PBAs).
• Understanding and controlling these spin states is key to designing efficient electrocatalysts.

Purpose of the Study:

• To investigate the effect of interfacial electric fields on the spin state of Fe centers in MnFeOx/PBA pre-catalysts.
• To enhance the electrochemical reconstruction kinetics and oxygen evolution reaction (OER) performance of PBAs.

Main Methods:

• Fabrication of MnFeOx/PBA pre-catalysts with an interfacial electric field.
• Electrochemical characterization including OER performance testing in simulated seawater.
• Analysis of electronic structure and metal-ligand backdonation.

Main Results:

• An interfacial electric field induced a partial high spin configuration of Fe centers, enhancing π backdonation.
• This electronic perturbation accelerated the transformation into active (oxy)hydroxide phases.
• The reconstructed catalyst (R-MnFeOx/PBA) achieved an ultralow OER overpotential (201 mV at 10 mA cm⁻²) and high stability (1150 h at 1000 mA cm⁻²).

Conclusions:

• Spin-state engineering is a viable strategy for pre-catalyst design, linking electronic structure to reconstruction-enhanced electrocatalysis.
• The R-MnFeOx/PBA catalyst demonstrates superior performance for OER in alkaline membrane electrode assemblies (MEAs).
• This approach offers a new pathway for developing advanced electrocatalysts.