New device produces critical fertilizer ingredient from thin air, cutting carbon emissions

The air around us contains a powerful solution to making agriculture more sustainable. Researchers at Stanford University and King Fahd University of Petroleum and Minerals in Saudi Arabia have developed a prototype device that uses wind energy to draw air through a grid to produce ammonia, a key fertilizer ingredient. The method they developed, if perfected, could eliminate the need for the century-old method of producing ammonia by combining nitrogen and hydrogen at high pressure and temperature. The old method consumes 2% of the world’s energy and contributes 1% of annual CO2 emissions due to its reliance on natural gas.

The study was published on December 13 in scientific progressinvolving the first live (rather than in a laboratory) demonstration of the technology. The researchers envision one day integrating the device into irrigation systems, allowing farmers to produce fertilizer directly from the air.

“This breakthrough allows us to harness nitrogen from the air and sustainably produce ammonia,” said the study’s senior author Richard Zare, a professor of natural sciences in Stanford’s School of Humanities and Sciences. “This is an important step towards a decentralized and eco-friendly approach to farming.”

A cleaner alternative

In preparing to design their device, the researchers studied how different environmental factors—such as humidity, wind speed, salt content, and acidity—affect ammonia production. They also studied how the size of the water droplets, the concentration of the solution and the contact of water with water-insoluble materials affected the process. Finally, they tested optimal mixtures of iron oxide and acidic polymers with fluorine and sulfur to determine the ideal conditions for ammonia production and to understand how these catalyst materials interact with water droplets.

The Stanford team’s process produces ammonia cleanly and cheaply, using ambient air to obtain nitrogen and hydrogen from water vapor. By passing air through a mesh coated with a catalyst to promote the necessary reactions, the researchers produced ammonia in high enough concentrations to be used as a hydroponic fertilizer in a greenhouse environment. Unlike traditional methods, the new technology operates at room temperature and standard atmospheric pressure and does not require an external voltage source to be connected to the grid. Farmers can run portable equipment on-site, eliminating the need to purchase and transport fertilizer from manufacturers.

“This approach significantly reduces the carbon footprint of ammonia production,” said Xiaowei Song, a research scientist in chemistry at Stanford University and lead author of the study.

In laboratory experiments, the team showed further potential by recycling water through a spray system, reaching ammonia concentrations sufficient to fertilize plants growing in the greenhouse after just two hours. By using filters made from microporous stone, this method can produce enough ammonia to support a wider range of agricultural applications.

A future without fossil fuels

The device is still two to three years away from being commercially available, said study co-author Chanbasha Basheer of King Fahd University of Petroleum and Minerals. At the same time, the researchers plan to use larger and larger grid systems to produce more ammonia. “There’s still a lot of room for development in this area,” Bascher said.

The importance of ammonia extends beyond fertilizers. As a clean energy carrier, it can store and transport renewable energy more efficiently than hydrogen due to its higher energy density. This innovation positions ammonia as key to decarbonizing industries such as shipping and power generation.

“Green ammonia represents a new frontier in sustainability,” Zahl said. “This approach, if economically scalable, could significantly reduce our dependence on fossil fuels across multiple industries.”

The research was funded by the U.S. Air Force Office of Scientific Research and King Fahd University of Petroleum and Minerals.