Dual-Atom Catalyst Breakthrough: Adjacent Magnesium Sites Optimize Iron Spin States for Record-Breaking Oxygen Reduction

New Fe-Mg dual-atom catalyst optimizes iron spin states to lower energy barriers, reaching record performance in fuel cells and zinc-air batteries.

By: AXL Media

Published: Apr 29, 2026, 4:06 AM EDT

Source: Information for this report was sourced from EurekAlert!

Overcoming Efficiency Barriers in Clean Energy

The global transition toward sustainable energy technologies faces a persistent bottleneck in the oxygen reduction reaction (ORR) at the cathode of fuel cells and metal-air batteries. While iron-based single-atom catalysts have long been considered the most promising non-precious metal alternatives to expensive platinum, their practical application has been limited by suboptimal electronic configurations. A research team from Shanghai Jiao Tong University has now addressed this limitation by developing a dual-atom catalyst that incorporates magnesium to fundamentally alter the behavior of iron at the atomic level.

The Role of Spin-State Regulation

In conventional iron catalysts, the iron atoms often exist in a low-spin state that creates unfavorable orbital interactions with oxygen intermediates. This configuration hinders the activation of oxygen molecules and the subsequent release of hydroxide ions, which are the primary rate-determining steps of the reaction. By positioning a magnesium site adjacent to the iron, the researchers triggered a transition from a low-spin to a medium-spin state. This shift optimizes the electronic "back-donation" from iron to oxygen, significantly accelerating the four-electron pathway required for efficient energy conversion.

Diagnostic Insights from Advanced Spectroscopy

The team utilized a suite of sophisticated diagnostic tools, including X-ray absorption spectroscopy and Mössbauer spectroscopy, to confirm the structural transformation within the catalyst. These measurements verified that the incorporation of magnesium effectively shifts the iron from an $S=0$ low-spin state to an $S=1$ medium-spin state. This precise electronic tuning reduces the binding strength of hydroxide intermediates, preventing the catalyst surface from becoming "clogged" and allowing for a much faster turnover of chemical products during operation.