Scalable ruthenium core-shell hydrogen catalyst for efficient and robust proton-exchange membrane electrolyser

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Proton-exchange membrane water electrolysers (PEMWE) are crucial for green hydrogen production.
• Current PEMWE technology heavily relies on expensive platinum-group metal catalysts.
• Cost-effective alternatives are needed to improve the economic viability of hydrogen generation.

Purpose of the Study:

• To develop and characterize a novel non-platinum catalyst for hydrogen evolution reaction (HER) in acidic media.
• To investigate the structure-activity relationship and reaction mechanism of the new catalyst.
• To demonstrate the scalability and performance of the catalyst in a practical PEMWE system.

Main Methods:

• Flame-assisted synthesis of a ruthenium oxide (RuO2) core/ruthenium phosphide (RuP2) shell catalyst.
• Electrochemical characterization including overpotential measurements at a specific current density.
• Density functional theory (DFT) calculations and mechanistic studies.
• Colloidal milling for scalable synthesis.
• Integration and testing in a proton-exchange membrane electrolyser.

Main Results:

• The RuO2/RuP2 core-shell catalyst achieved an overpotential of 16 mV at 10 mA cm-2 with low catalyst loading (5.5 wt%).
• DFT and mechanistic studies revealed optimized interfacial water organization and enhanced proton transfer.
• Scalable synthesis via colloidal milling produced tens of grams per batch under mild conditions.
• The catalyst demonstrated stable operation at 1 A cm-2 and 1.8 V for over 1,500 hours in a PEMWE.

Conclusions:

• The developed RuO2/RuP2 core-shell catalyst is a promising, cost-effective, non-platinum alternative for PEM electrolysis.
• The unique core-shell structure enhances catalytic activity and stability for hydrogen evolution.
• Scalable synthesis methods enable potential industrial application, reducing reliance on precious metals.