Market and product

Compiled by Bao Hien

From advances in catalysts to the use of renewable electricity, light and plasma, emerging technologies are seeking to produce ammonia under less demanding conditions than those required by conventional processes. Although some laboratory studies have achieved high performance, production costs, equipment durability and scalability remain major challenges before these technologies can compete with established methods.

Ammonia is a key raw material for nitrogen fertilisers and is also used in hydrogen storage and the chemical industry. With global demand reaching approximately 200 million tonnes a year, finding less energy-intensive ways to produce it could benefit the fertiliser industry and support efforts to reduce emissions.

For more than a century, ammonia production has relied primarily on the Haber–Bosch process. It combines nitrogen from the air with hydrogen at temperatures of 400–500°C and pressures of 100–200 atmospheres, using an iron-based catalyst. Despite decades of optimisation, the process still consumes about 2% of global energy and generates substantial carbon emissions.

The main challenge is the strong triple bond between nitrogen atoms, which requires considerable energy to break. Researchers are therefore exploring alternative ways to activate the reaction, ranging from improved catalysts to electricity, light and plasma.

New Catalysts Could Lower Reaction Temperatures

One research direction focuses on catalysts that can accelerate ammonia synthesis under milder conditions. In 2017, a system combining transition metals with lithium hydride (LiH) enabled nitrogen fixation at temperatures below 300°C.

In 2025, researchers used nickel with defect-rich barium carbide (BaC₂) to produce ammonia at 100°C and atmospheric pressure. However, the production rate was only 0.20 mmol per gram per hour, indicating that productivity still needs to improve substantially.

Artificial intelligence is also beginning to support catalyst discovery. Instead of testing compounds one by one, researchers can use machine learning to screen data and identify promising material structures.

Using data from 201 ruthenium-containing intermetallic compounds, one research team designed a Sc₁/₈Nd₇/₈Ru₂ catalyst. It achieved an ammonia production rate of 9.03 mmol per gram per hour at 0.9 MPa and 325–400°C, maintaining stable performance for 105 hours.

Another approach uses nitric oxide (NO) rather than molecular nitrogen. Because the bond in NO is weaker, it is easier to hydrogenate. An FeCu/TiO₂ catalyst achieved 97.7% ammonia selectivity at 350°C and atmospheric pressure. However, its ability to operate across a wider temperature range and tolerate oxygen remains limited.

Electrochemical Production: Potential to Use Renewable Energy

Electrochemical ammonia synthesis is attracting interest because it can use electricity generated from renewable sources. If successfully developed, it could offer more flexible production options alongside large-scale Haber–Bosch plants.

However, reducing nitrogen in water presents a major obstacle. Nitrogen has low solubility, while the competing hydrogen-evolution reaction proceeds six to eight orders of magnitude faster. As a result, much of the electricity is consumed by the side reaction rather than ammonia production.

In 2022, a lithium-mediated method using an organic solvent to suppress hydrogen evolution achieved a Faradaic efficiency close to 100%. This was a significant laboratory result, but it did not guarantee economic viability. The process consumes about four lithium ions per ammonia molecule, with estimated costs more than three times those of the Haber–Bosch process. Surface films can reduce lithium activity, while lithium dendrites may cause short circuits and create safety risks during scale-up.

A different electrochemical approach converts NO into ammonia. The copper–tin alloy Cu₆Sn₅ achieved Faradaic efficiency above 96% at current densities exceeding 1,400 mA/cm² and remained stable for 135 hours.

In 2025, an 8-litre flow reactor using a Ru₉Co₉₁ alloy continuously produced 8.5 litres of ammonium nitrate fertiliser solution per hour. The reported output was sufficient for drip irrigation over 20 m² of crops, demonstrating a potential link between electrochemical research and agricultural inputs.

Feedstock availability remains a bottleneck. NO is toxic, and high-purity supplies are limited. Nitrogen oxides in exhaust gases are generally dilute and dispersed, making it difficult to collect enough material for large-scale production.

For nitrate reduction, a Co₆Ni₄ catalyst achieved a Faradaic efficiency of 99.21% and operated for 120 hours. However, most catalysts in this category still work at current densities below 300 mA/cm², which is generally insufficient for industrial applications.

Using Light and Plasma to Drive Reactions

Photocatalysis uses light energy to promote ammonia production at ambient temperature and pressure. If sufficiently efficient, the technology could reduce the need for energy from conventional sources.

At present, however, the solar-to-ammonia energy conversion efficiency of most systems remains below 0.1%, limiting their practical potential. One promising application uses an Au/TiO₂ catalyst to convert NO in exhaust gases into ammonia, potentially combining pollution control with the production of feedstock for liquid fertilisers.

Low-temperature plasma offers another route by activating nitrogen molecules without maintaining the entire system at the high temperatures required by conventional processes. Its main challenges are improving reaction selectivity and energy efficiency.

Two-Step Processes: Promising Laboratory Results, Uncertain Economics

Rather than converting nitrogen directly into ammonia, some researchers are exploring a two-step process. Plasma first oxidises nitrogen in the air into nitrogen oxides (NOₓ), which are then converted into ammonia through catalytic or electrochemical reactions.

In 2024, a system combining plasma and electrocatalysis, using air as its feedstock, achieved a production rate of 3 mmol/cm² per hour, a Faradaic efficiency of 92% and stable operation for 100 hours under ambient conditions. In 2025, a plasma–photocatalysis system achieved 98.33% ammonia selectivity and operated for 240 hours.

Despite these results, techno-economic assessments highlight a substantial gap between laboratory performance and commercial viability. Plasma oxidation converts only 0.25–7% of the input energy, consuming 300–440 kJ per mole of ammonia—around 1.5–2 times the energy required by Haber–Bosch. Separating and purifying NO accounts for 30–40% of the system's total energy consumption.

Overall energy efficiency is estimated at just 5–25%. Equipment costs are three to five times higher, while electrode corrosion can reduce equipment life to less than two years. The estimated levelised cost of ammonia production is USD 1.8–2.5 per kilogram, substantially above the USD 0.5–0.8 per kilogram associated with Haber–Bosch.
These figures show that high reaction efficiency alone does not make a technology commercially competitive. Energy use, equipment costs, product separation and long-term operational durability all affect the final cost of fertiliser.

Reliable Measurement Remains a Challenge

Beyond technical and economic barriers, researchers must accurately determine how much ammonia has actually been produced. In many emerging technologies, yields are measured in micromoles, making results particularly vulnerable to contamination and analytical errors.

The indophenol blue method is widely used to quantify ammonia, but iron and molybdenum ions can interfere with the measurement and produce artificially high results. Oxidation products from sacrificial agents such as methanol may also interfere, creating apparent ammonia that does not reflect the intended reaction.

To confirm that ammonia has genuinely been produced from molecular nitrogen, researchers can use nitrogen-15 (¹⁵N₂) isotope-labelling experiments. However, according to the cited material, more than 60% of published studies on photocatalytic nitrogen reduction do not report this control test.

Recommended practices include using three blank controls in each experimental series, verifying results with ¹⁵N₂, comparing indophenol blue measurements with ion chromatography and investigating contamination whenever the results differ by more than 15%.

From Laboratory Inventions to Innovation in Fertiliser Production

Emerging research is broadening ammonia production beyond a single high-temperature, high-pressure process. New approaches include advanced catalysts, electrochemistry, photocatalysis and plasma. Some have demonstrated high selectivity, stable operation lasting hundreds of hours or the ability to produce fertiliser solutions in flow reactors.

Three priorities stand out for further development: improving catalysts for one-step processes, reducing energy use and separation costs in two-step systems, and standardising measurement methods to ensure that results are reliable and comparable.

For the fertiliser industry, the ultimate goal is not simply to produce ammonia through new technologies. It is to manufacture this essential feedstock at competitive cost while reducing energy consumption and emissions and maintaining a reliable supply. Achieving that goal will require solutions to challenges involving lithium costs, equipment investment, durability and production scale.

The Haber–Bosch process is likely to remain dominant in the near term because of its proven economics and established industrial scale. Emerging technologies should therefore be viewed as developing innovation pathways rather than immediate replacements. Their potential integration with renewable electricity, exhaust-gas treatment systems and more flexible fertiliser production models will be worth watching as the industry seeks to reduce its energy and carbon footprints.