Imagine accelerating chemical reactions thousands of times simply by applying a magnetic field. That’s precisely what researchers at Tohoku University in Japan have accomplished.

Their recent study reveals that external magnetic fields can finely tune the spin state of single-atom catalysts (SACs), significantly improving their performance. This breakthrough has the potential to transform ammonia production for fertilizers and enhance wastewater treatment, all while minimizing energy usage and environmental impact. According to Hao Li, a researcher at Tohoku University, “More efficient production processes can reduce costs, which may translate into lower prices for products such as fertilizers and treated water at the consumer level.”

traditionally, efforts to improve catalysts have focused on altering their composition or structure. however, controlling quantum-level phenomena, especially the spin state of electrons (which governs molecular interactions on a catalyst’s surface), has been a major hurdle.

The study authors have overcome this limitation with a novel approach that allows direct manipulation of these spin states.

Magnetic Field Enhances Catalyst Power

Single-atom catalysts (SACs) are materials where individual metal atoms are dispersed to accelerate chemical reactions. Unlike conventional catalysts that use clusters of metal atoms, SACs utilize single atoms.

This design maximizes efficiency because every atom is exposed and available for reaction, leading to faster, more efficient, and cost-effective processes.

In their study,the researchers investigated a catalyst composed of ruthenium atoms (Ru) anchored on a carbon and nitrogen surface,known as Ru-N-C.While these SACs are already quite effective,the team aimed to further enhance their performance.

By applying an external magnetic field to the catalyst,they observed a remarkable phenomenon: the field induced a shift in the electrons’ spin state,transitioning them to a high-spin state. Essentially, the magnetic field provided the catalyst atoms with extra energy, causing them to operate more rapidly.

The researchers evaluated this method by facilitating electrochemical nitrate reduction, a process where nitrate ions (NO₃⁻) in wastewater are chemically converted into ammonia (NH₃) using electricity and a catalyst.

They discovered that the magnetic field enhanced the catalyst’s ability to bind to nitrate molecules in wastewater, streamlining the reaction and boosting ammonia production.

“When exposed to an external magnetic field, the Ru-N-C electrocatalyst demonstrated a high NH3 yield rate (~38 mg L-1 h-1) and a Faradaic efficiency…of ~95% for over 200 hours.”

“When exposed to an external magnetic field, the Ru-N-C electrocatalyst demonstrated a high NH3 yield rate (~38 mg L-1 h-1) and a Faradaic efficiency (a measure of how well electrons are used) of ~95% for over 200 hours,” the study authors note.

This Small Tweak Can Lead to Big Changes

The researchers employed refined instruments to precisely monitor the changes in the catalyst’s spin states under the magnetic field. These observations confirmed that magnetic fields can significantly enhance catalyst performance,a finding that had not been previously demonstrated so effectively in electrocatalysis.

This research has significant implications for industries reliant on electrochemical processes.For example,ammonia is a crucial component of fertilizers,and more efficient production could reduce global food production costs. Similarly, improved wastewater treatment could benefit both the surroundings and public health by enabling faster and cheaper water purification.

Furthermore, this approach is not limited to a single type of chemical reaction.Prior research indicated that applying a magnetic field to a nickel-based catalyst increased its performance by an astounding 2,880 percent during water splitting into hydrogen and oxygen.

This suggests that magnetic field-driven catalysis could lead to breakthroughs in various fields, including green energy production (e.g., large-scale hydrogen fuel production, similar to ammonia). However, this novel approach is still in its early stages.

Implementing magnetic fields on a large scale in industrial settings presents challenges and requires substantial equipment. The researchers are now focused on developing solutions to these issues.

The study is published in the journal Nano Letters.