Why weak-binding M鈥揘鈥揅 catalysts defy expectations in oxygen reduction reactions

A new study has challenged conventional wisdom on oxygen reduction reaction (ORR) catalysts by uncovering a novel reaction pathway in weak-binding metal鈥搉itrogen鈥揷arbon (M鈥揘鈥揅) single-atom catalysts (SACs). These findings, now in the Journal of the American Chemical Society, could revolutionize the design of next-generation electrocatalysts for clean energy applications.
Traditionally, optimal ORR catalysts were believed to follow the Sabatier principle, where moderate binding strength at metal active sites enhances catalytic performance. However, weak-binding SACs, such as Ni鈥揘鈥揅 and Cu鈥揘鈥揅, exhibit unexpectedly high ORR activity, contradicting this principle.
By integrating a pH-dependent microkinetic model with advanced synchrotron spectroscopy, the research team discovered that atomic oxygen (O*) adsorption at the metal-nitrogen bridge site鈥攔ather than the conventional metal atop site鈥攊s a crucial step in the ORR mechanism for weak-binding catalysts. This adsorption alters key reaction barriers and scaling relations, offering new insights into their exceptional catalytic behavior.
"These results not only redefine our understanding of weak-binding M鈥揘鈥揅 catalysts but also provide a new strategic direction for catalyst design," said Di Zhang, an assistant professor at Tohoku University's Advanced Institute of Materials Research (WPI-AIMR). "By leveraging our findings, we can optimize weak-binding M鈥揘鈥揅 catalyst structures for improved performance across different pH environments."
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pH-electric field coupled microkinetic modeling for weak-binding M鈥揘鈥揅 catalysts. Credit: Journal of the American Chemical Society (2025). DOI: 10.1021/jacs.4c16733 -
Experimental validation of the weak-binding M鈥揘鈥揅 activity model. Credit: Journal of the American Chemical Society (2025). DOI: 10.1021/jacs.4c16733
Looking ahead, the research team plans to integrate machine learning force fields with studies on new reaction pathway exploration to accelerate the prediction and design of high-performance electrocatalysts.
The structures in this research have been made available through the Digital Catalysis Platform (), the largest experimental catalysis database to date, developed by the Hao Li Lab.
More information: Di Zhang et al, Why Do Weak-Binding M鈥揘鈥揅 Single-Atom Catalysts Possess Anomalously High Oxygen Reduction Activity?, Journal of the American Chemical Society (2025).
Journal information: Journal of the American Chemical Society
Provided by Tohoku University