Accelerating the Pace of Oxygen Evolution Reaction Catalyst Discovery through Megalibraries.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Iridium (Ir) catalysts are critical for the oxygen evolution reaction (OER) in proton-exchange membrane water electrolyzers (PEMWEs).
• High cost, scarcity, and slow discovery rates of Ir alternatives hinder widespread PEMWE adoption.
• The vast design space for catalysts makes identifying non-Ir alternatives challenging.

Purpose of the Study:

• To accelerate the discovery of non-iridium catalysts for the acidic oxygen evolution reaction (OER).
• To explore a high-throughput screening approach using a "megalibrary" of nanostructures.
• To identify promising alternative catalysts for proton-exchange membrane water electrolyzers (PEMWEs).

Main Methods:

• A "megalibrary" of approximately 156 million distinct nanostructures composed of Ru, Co, Mn, and Cr was synthesized and screened.
• Over 40 RuCoMnCr oxide candidates were selected, scaled up, and their catalytic performance evaluated.
• Correlation between megalibrary screening and macroscopic sample performance was assessed (r = 0.84).

Main Results:

• A novel Ru52Co33Mn9Cr6 oxide catalyst demonstrated high activity for OER.
• In a PEMWE, this catalyst achieved 1.58 V at 1 A/cm² and 1.77 V at 3 A/cm².
• The catalyst exhibited excellent stability, operating over 1000 hours at 1 A/cm² with minimal voltage increase (57 μV/h).

Conclusions:

• This study presents a successful strategy for rapid catalyst discovery using a high-throughput screening platform.
• The developed RuCoMnCr oxide catalyst is a promising, cost-effective alternative to iridium for PEMWEs.
• The platform generates large datasets to facilitate AI and machine learning in catalyst design for energy conversion.