A new device produces ammonia from air and wind energy, offering a sustainable alternative to fossil fuel-dependent methods for agriculture and clean energy applications.
The air we breathe holds the key to more sustainable agriculture, thanks to an innovative breakthrough by researchers at Stanford University and King Fahd University of Petroleum and Minerals in Saudi Arabia. They have created a prototype device that uses wind energy to extract nitrogen from the air and convert it into ammonia—a critical ingredient in fertilizer.
If fully developed, this method could replace the traditional process of producing ammonia, which has been in use for over a century. The conventional method combines nitrogen and hydrogen at high pressures and temperatures, consuming 2% of the world’s energy and generating 1% of annual carbon dioxide emissions due to its reliance on natural gas. This new approach offers a cleaner, more energy-efficient alternative.
The study, published December 13 in Science Advances, involved the first on-site – rather than in a lab – demonstration of the technology. The researchers envision someday integrating the device into irrigation systems, enabling farmers to generate fertilizer directly from the air.
“This breakthrough allows us to harness the nitrogen in our air and produce ammonia sustainably,” said study senior author Richard Zare, the Marguerite Blake Wilbur Professor in Natural Science in the Stanford School of Humanities and Sciences. “It’s a significant step toward a decentralized and eco-friendly approach to agriculture.”
A cleaner alternative
In preparation for designing their device, the researchers studied how different environmental factors – like humidity, wind speed, salt levels, and acidity – affect ammonia production. They also looked at how the size of water droplets, the concentration of the solution, and the contact of water with materials that do not dissolve in water impact the process. Lastly, they tested the best mix of iron oxide and an acid polymer with fluorine and sulfur to determine the ideal conditions for producing ammonia and understand how these catalyst materials interact with water droplets.
The Stanford team’s process makes ammonia cleanly and inexpensively and utilizes the surrounding air to get nitrogen and hydrogen from water vapor. By passing air through a mesh coated with catalysts to facilitate the necessary reaction, the researchers produced enough ammonia with a sufficiently high concentration to serve as a hydroponic fertilizer in greenhouse settings. Unlike traditional methods, the new technique operates at room temperature and standard atmospheric pressure, requiring no external voltage source to be attached to the mesh. Farmers could run the portable device onsite, eliminating the need to purchase and ship fertilizer from a manufacturer.
“This approach significantly reduces the carbon footprint of ammonia production,” said study lead author Xiaowei Song, a chemistry research scientist at Stanford.
In laboratory experiments, the team demonstrated further potential by recycling water through a spraying system, achieving ammonia concentrations sufficient to fertilize plants grown in a greenhouse after just two hours. By incorporating a filter made from a microporous stone material, this approach could produce enough ammonia to support broader agricultural applications.
A future without fossil fuels
The device is two to three years away from being market-ready, according to study co-author Chanbasha Basheer of King Fahd University of Petroleum and Minerals. In the meantime, the researchers plan to use increasingly large mesh systems to produce more ammonia. “There is a lot of room to develop this,” Basheer said.
Ammonia’s importance extends beyond fertilizers. As a clean energy carrier, it can store and transport renewable energy more efficiently than hydrogen gas due to its higher energy density. The innovation positions ammonia as a linchpin in decarbonizing industries like shipping and power generation.
“Green ammonia represents a new frontier in sustainability,” Zare said. “This method, if it can be scaled up economically, could drastically reduce our reliance on fossil fuels across multiple sectors.”
Reference: “Onsite ammonia synthesis from water vapor and nitrogen in the air” by Xiaowei Song, Chanbasha Basheer, Jinheng Xu and Richard N. Zare, 13 December 2024, Science Advances.
DOI: 10.1126/sciadv.ads4443
The study was funded by the U.S. Air Force Office of Scientific Research and King Fahd University of Petroleum and Minerals.
