A domestic research team has developed a technology that can eliminate almost 100% of nitrous oxide (N₂O), a greenhouse gas 310 times stronger than carbon dioxide, even at room temperature. Expectations are rising that it will greatly help reduce greenhouse gases and achieve carbon neutrality by efficiently treating nitrous oxide emitted from automobile exhaust and chemical processes.
Professor Baek Jong-beom and colleagues in the Department of Energy and Chemical Engineering at Ulsan National Institute of Science and Technology (UNIST) said on the 21st that they have developed, for the first time in the world, a new technology that decomposes nitrous oxide using the impact and friction generated when beads collide.
Nitrous oxide is commonly known as "laughing gas," but in reality it is a much stronger greenhouse gas than carbon dioxide. It mainly occurs in chemical plants and diesel engine exhaust and is cited as one of the main causes of ozone layer depletion. The problem is that this gas is so stable that, with existing technology, it could only be decomposed at high temperatures above 445 degrees Celsius, resulting in very high energy consumption.
The research team broke through this limitation with "mechanical energy." They devised a process in which a container (ball mill) containing beads a few millimeters in diameter is loaded with a nickel oxide (NiO) catalyst and nitrous oxide gas and then shaken rapidly.
The impact and friction generated as the beads collide create small defects on the catalyst surface. Thanks to these defects, nitrous oxide decomposes easily even at low temperatures.
In experiments, 99.98% of nitrous oxide was decomposed at 42 degrees Celsius. Energy efficiency was also more than six times higher than the conventional high-temperature method (445 degrees, conversion rate 49%).
The research team also tested the method in actual diesel engine exhaust and chemical plant emission environments and confirmed that up to more than 97% of nitrous oxide was decomposed. Processes adopting the team's technology operated stably even in environments mixed with oxygen and moisture, and the expense was one-eighth that of conventional high-temperature processes.
Baek said, "Since last year, Europe has implemented the Euro VII emissions regulation, which includes nitrous oxide as a new regulated item," adding, "This technology will be a great help in reducing greenhouse gases not only in automobiles and chemical processes but also in ship engines that use ammonia fuel."
The research findings were published on the 26th of last month in Advanced Materials, a leading journal in materials and energy.
References
Advanced Materials (2025), DOI: https://doi.org/10.1002/adma.202511666