MRI-Visualized Aqueous Microenvironment Engineering in 3D Hierarchical FePt Catalysts with Macroporous Architecture...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrolytic water splitting is key for sustainable hydrogen production.
• Alkaline hydrogen evolution reaction (HER) is kinetically limited by water dissociation and adsorption.
• Advanced catalysts are needed to overcome these limitations.

Purpose of the Study:

• To design a 3D hierarchical FePt catalyst (FePt@3D) to enhance interfacial water-catalyst interactions.
• To utilize magnetic resonance imaging (MRI) to map water distribution at catalytic interfaces.
• To improve the efficiency of the alkaline hydrogen evolution reaction.

Main Methods:

• Fabrication of a micrometer-scale 3D hierarchical FePt catalyst system.
• Employing spatiotemporally resolved T2-weighted imaging (T2-WI) to visualize water distribution.
• Electrochemical measurements to determine catalytic performance (overpotential).

Main Results:

• The FePt@MP-3D catalyst achieved 28% water enrichment via capillary forces and increased tortuosity.
• The catalyst exhibited a low overpotential of 13.8 mV at 10 mA cm-2, outperforming commercial Pt/C (14.4 mV).
• MRI successfully mapped water distribution, correlating it with catalytic activity.

Conclusions:

• MRI is a transformative tool for understanding water distribution in electrocatalysis.
• The developed FePt@3D catalyst significantly enhances alkaline HER performance.
• This approach can be applied to other water/ion-transfer-dependent electrocatalytic reactions like CO2 reduction and oxygen reduction.