Electrochemical synthesis of green ammonia from water and air

R&D Focus Areas:
Direct hydrogen carrier production, Electrolysis, Ammonia

Lead Organisation:
CSIRO

Partners:
Griffth University, Korea Institute of Energy Research

Status:
Active

Start date:
January 2019

Completion date:
June 2025

Key contacts:
Gurpreet Kaur – Gurpreet.Kaur@csiro.au

Funding:
CSIRO Hydrogen Future Science Program

Project total cost:
AUD$694,000

Project summary description:
Recently, the electrochemical route of green hydrogen production from water has attracted worldwide attention due to the increasing availability of renewable energy sources. However, hydrogen storage and distribution are still dominating sectors.

Ammonia contains 17.6 wt.% of H₂ and can also be used as a hydrogen carrier. Ammonia has high volumetric energy density and is easier to store and transport. To produce green ammonia, current technologies are considering producing green hydrogen from water electrolysis, avoiding natural gas steam reforming. This helps to mitigate the significant carbon emissions (1.83 tCO₂/tNH₃ emitted by the current route). The produced hydrogen is then used in conventional reactors for ammonia synthesis. However, the process is still energy intensive as high temperatures (~450°C) and high pressures (~200 bar) are required for ammonia production with single-pass ammonia yields of only 15.5 vol%.

In the proposed work, ammonia can be synthesized using air and H₂O as the feedstocks using the electrochemical route at atmospheric pressure. In addition, no air separation units are required for N₂ feedstock. This can be a sustainable route to store and transport renewable energy in the form of value-added clean fuels to areas lean in renewables.

The project will research and develop an electro-catalysts/electrochemical interface, other cell materials/cell fabrication/assembly, and perform electrolysis cell evaluation and results analysis. The CSIRO team efforts are to produce green ammonia production rates comparable to Haber Bosch recorded with novel developed catalysts.

Related publications and key links:

1. Ammonia as a Renewable Energy Transportation Media https://pubs.acs.org/doi/full/10.1021/acssuschemeng.7b02219
2. Engineering a solid-state metalloprotein hydrogen evolution catalyst- https://www.nature.com/articles/s41598-020-60730-y
3. Insights into nitrogenase bio electrocatalysis for green ammonia production https://doi.org/10.1002/cssc.202001433
4. Rhodium-molybdenum oxide electrocatalyst with dual active sites for electrochemical ammonia synthesis under neutral pH condition- https://doi.org/10.1016/j.jelechem.2021.115157
5. Green ammonia synthesis using CeO2/RuO2 nanolayers on vertical graphene catalyst via electrochemical route in alkaline electrolyte. https://doi.org/10.1039/D1NR06411H

CSIRO ‘Future Science Platforms: Hydrogen Energy Systems’: Direct ammonia synthesis by alkaline membrane-based electrolysis – Hydrogen Energy Systems (csiro.au)

Higher degree studies supported:
One PhD student is supported in collaboration with Griffth University.

 

Reviewed: July 2024