Blog icon


What is it?

Membrane based ammonia synthesis is a method in which hydrogen gas is supplied on one side of a dense metallic membrane and nitrogen gas on the other. The structure of the membrane allows individual hydrogen atoms to pass through to the nitrogen gas side and react to form ammonia.

Why is it important?

Membrane based ammonia synthesis offers a near-term opportunity to achieve significant reductions in operating costs and carbon emissions compared to the traditional Haber-Bosch process.


  • Volumetric hydrogen density: High (10.7kg H2 / m3 at 10 bar and 25°C)
  • Gravimetric hydrogen density: High (17.8% by mass)
  • Storage conditions: Liquid at ambient temperature, 10-11 bar pressure


  • Low pressure ammonia synthesis – allows direct coupling of reactor to electrolyser and air separation unit
  • Less capital intensive than Haber-Bosch synthesis
  • Highest non-Haber-Bosch synthesis rate achieved
  • Fast switch-on/off times can accommodate intermittent energy sources
  • Centralised or decentralised ammonia production possible


  • Does not allow direct synthesis of ammonia from nitrogen and water

RD&D priorities

  • Improve conversion efficiency to ~15% (from ~4%)
  • Demonstrate use of lower-cost membranes
  • Improve production rate
  • Utilise lower-cost catalysts

Known active organisations


Other opportunities like this

  • Ammonia is synthesised by reacting hydrogen with nitrogen gas at high temperatures and pressures.

  • Hydrogen is reacted with toluene to form methylcyclohexane (MCH), a compound that can be transported at ambient temperature and pressure.

  • Methanol is conventionally synthesised at large scale from synthesis gas (or syngas), a mixture of hydrogen and carbon monoxide typically at an H₂/CO ratio of 1.8 ~ 2.2, derived through steam reforming of natural gas or steam gasification of coal.

Contact us

Find out how we can help you and your business. Get in touch using the form below and our experts will get in contact soon!

CSIRO will handle your personal information in accordance with the Privacy Act 1988 (Cth) and our Privacy Policy.

First name must be filled in

Surname must be filled in

I am representing *

Please choose an option

Please provide a subject for the enquriy

0 / 100

We'll need to know what you want to contact us about so we can give you an answer

0 / 1900

You shouldn't be able to see this field. Please try again and leave the field blank.