Nium, a UK-based cleantech startup founded in 2022, has developed an innovative technology for ammonia synthesis. Their process utilizes a heterogeneous catalyst comprising metallic atom clusters on the surface of microparticles to facilitate the reaction between green hydrogen and nitrogen under low temperature and pressure conditions. This approach significantly reduces energy consumption and carbon emissions compared to the traditional Haber-Bosch ammonia production process.
Challenges: green ammonia
Ammonia is a vital chemical commodity with widespread applications. It serves as the foundation for fertilizers that underpin modern agriculture, contributing to about half of global food production. Beyond agriculture, ammonia shows promise as a renewable energy storage and transport medium. Its potential is being explored in various sectors, including Samsung in shipping, Toyota in automotive, and Boeing and NASA in aircraft, owing to its superior energy density compared to lithium-ion batteries and compressed hydrogen.
However, conventional ammonia production is a significant contributor to global carbon emissions. The process, which involves steam methane reforming, water-gas shift reaction, and the Haber-Bosch process, consumes approximately 1.8% of global energy output annually. This results in the emission of about 500 million tons of carbon dioxide, accounting for roughly 1.8% of global carbon dioxide (COâ‚‚) emissions.
Given the environmental impact of current production methods, there is an urgent need to develop more sustainable approaches to ammonia synthesis.
Nium Technology
The Haber-Bosch process, utilizing iron-based catalysts, is the current industrial method for ammonia synthesis:
N₂ + H₂ ⇆ NH₃
This process operates under extreme conditions, requiring pressures exceeding 150 bar and temperatures above 400 ºC to break the strong N-N triple bond in nitrogen gas (N₂).
A more sustainable approach to ammonia synthesis, operating at lower pressures and temperatures, is highly desirable. Electrochemical ammonia synthesis, which can occur at room temperature and ambient pressure, is one such promising alternative. This method requires stable electrocatalysts capable of producing ammonia with high yields and faradaic efficiency. Several startups, including NitroFix, are working to commercialize this technology.
Masashi Hatton and colleagues have developed a novel heterogeneous catalyst for ammonia synthesis that operates at just 1 bar and 50 ºC (also ref. JP2022070143A). This catalyst consists of ruthenium (Ru) nanoparticles deposited on a cubic CaFH solid solution. The catalyst is created by introducing fluoride anions into calcium hydride, resulting in a stable electron-donating material. However, the fabrication of this complex system remains challenging.
Nium has developed an innovative technology for green ammonia synthesis that operates under milder conditions than conventional methods. This process utilizes a novel heterogeneous catalyst to produce ammonia from green hydrogen and nitrogen at temperatures below 250 ºC and pressures under 30 bar.
The key to this technology is the heterogeneous catalyst that comprises metallic atom clusters supported on microparticles, allowing for efficient ammonia production. The fabrication of this heterogeneous catalyst system employs physical vacuum deposition (PVD) technology, making it cost-effective for large-scale production.
Nium's technology offers the potential for localized green ammonia production using renewable energy-powered machines at the point of use, such as on farms. This approach allows for on-demand ammonia generation, which can be directly introduced into irrigation systems or stored as an ammonia solution for use as fertilizer.
Nium’s catalyst for green ammonia synthesis
The diagram below depicts Nium’s heterogeneous catalysts comprising metallic atom clusters supported on the surface of a microparticle.