Stanford Scientists Unlock the Secret to Generating Ammonia Fuel from Air

Numerous green energy initiatives in laboratories are reporting remarkable findings—but what’s even more astounding is when these outcomes stem from a genuine on-site pilot project in the real world. This is exemplified by groundbreaking research that successfully generates ammonia from thin air, without necessitating an outside power source.

This method was innovated by a research team from Stanford University and King Fahd University of Petroleum and Minerals in Saudi Arabia. It utilizes a fine mesh that is coated with catalysts to merge atmospheric nitrogen with hydrogen obtained from water vapor, producing ammonia (NH₃).

Ammonia has historically been an essential element of fertilizers for agricultural crops; however, its significance has grown as a viable fuel option. When decomposed, ammonia releases hydrogen for fuel cells and internal combustion engines, generating only water with no carbon emissions during combustion. Moreover, ammonia can contain considerably more energy in a specified volume than hydrogen at a much cheaper rate per kilowatt hour. The shipping sector is one of the primary areas targeted for this type of technology, and a certain company has already introduced an ammonia-powered tugboat as a demonstration vessel.

Conventional methods for ammonia synthesis typically demand elevated temperatures and pressures, a technique that can lead to carbon emissions by utilizing methane as the raw material. The latest study, published on 13 December in Science Advances, illustrates how ammonia can be produced without relying on electricity or any other external energy input. The entire process takes place at ambient temperature and normal atmospheric pressure.

Extracting Ammonia From Thin Air

The mechanism is founded on a micromesh coated with catalysts. When water vapor (H₂O) interacts with atmospheric nitrogen (N₂), ammonia (NH₃) and oxygen (O₂) are produced. The resultant ammonia is then concentrated in a water solution, which can be enhanced using a zeolite filter to absorb and concentrate the ammonia. (Zeolite is frequently employed to eliminate ammonia during wastewater processing.)

The process can be effectively driven by natural wind, allowing the water vapor to flow through the mesh. The researchers conducted field tests in locations near both saline and freshwater sources to determine if varying humidity levels would affect output. While wind speed influenced ammonia production, it did not significantly affect outcomes when wind speeds ranged between 8 to 21 kilometers per hour; within those parameters, production remained relatively consistent.

The mesh’s coating is composed of iron oxide and Nafion, a fluoropolymer-copolymer material that is frequently utilized in fuel cells. Simply allowing air containing water droplets (in conjunction with atmospheric nitrogen) to circulate through the mesh initiates a series of reactions that culminates in ammonia generation. The production rate can be hastened by continuously spraying water droplets.

The researchers examined a field model in nine distinct locations in the San Francisco Bay region, achieving varying production rates influenced by temperature, humidity, and wind speed, thereby showcasing its potential for practical application if it can be manufactured economically.

The system yields an ammonia solution that could be used directly as a fertilizer for crops, thereby reducing or eliminating the necessity to purchase and transport conventional nitrogen fertilizers. When scaled, this system has the potential to produce commercial amounts of ammonia suitable for a sustainable green energy resource.

As per Richard Zare, a chemistry professor at the Stanford School of Humanities and Sciences, “this advancement could fundamentally transform the fertilizer production landscape by offering a more sustainable, cost-effective substitute to centralized manufacturing.” The water droplet technology possesses “the ability to revolutionize chemical practices—from empowering farmers in developing nations to enhancing pharmaceutical and industrial uses.”