Stabilizing Lattice Oxygen Mechanism on Ru Single Atoms via a High-Entropy Support for Acidic Oxygen Evolution

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• The lattice oxygen mechanism (LOM) enhances acidic oxygen evolution reaction (OER) activity but suffers from catalyst degradation due to defect accumulation.
• Achieving both high activity and long-term stability in OER catalysts remains a significant challenge.

Purpose of the Study:

• To develop a novel catalyst that stabilizes the LOM pathway, thereby improving both activity and durability for OER.
• To investigate the role of high-entropy oxides in conjunction with single-atom anchoring for enhanced catalytic performance.

Main Methods:

• Anchoring Ruthenium (Ru) single atoms onto a high-entropy oxide (FeCoNiCrMn)3O4 support.
• Investigating the electronic structure and hybridization between Ru 4d and O 2p orbitals.
• Analyzing the interfacial water structure and hydrogen-bonding network.
• Evaluating catalytic performance in acidic media (0.5 M H2SO4) and in a proton exchange membrane electrolyzer.

Main Results:

• The Ru-(FeCoNiCrMn)3O4 catalyst demonstrated a stabilized LOM pathway with enhanced Ru 4d-O 2p hybridization.
• A dynamic defect-refilling process was observed, preserving catalyst structure and preventing degradation.
• Achieved an overpotential of 204 mV for 10 mA cm-2 and a mass activity of 5235.42 A gRu-1 at 1.50 V vs RHE.
• Demonstrated stable operation for over 320 hours at 500 mA cm-2 in a proton exchange membrane electrolyzer.

Conclusions:

• Anchoring Ru single atoms on high-entropy oxides provides a viable strategy for simultaneously enhancing OER activity and catalyst stability.
• The high-entropy effect and dynamic defect refilling are crucial for the improved performance and durability.
• This approach offers a promising pathway for developing next-generation OER catalysts for applications like water splitting.