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Volume 66, Issue 3
  • ISSN: 2056-5135


Most of the global production of ammonia requires fossil fuels and is associated with considerable greenhouse gas emissions. Replacing fossil fuel ammonia with green or zero-carbon ammonia is a major focus for academia, industry and governments. Ammonia is a key component in fertiliser but is also attracting increasing interest as a carbon-free fuel for the maritime sector and as a hydrogen vector. This review describes the use of green (electrolysed) hydrogen in conventional Haber-Bosch plants and predicts adoption of the technology by 2030. Further into the future, direct green ammonia synthesis by electrocatalytic and photocatalytic means may present a cost-effective alternative to the Haber-Bosch process. Electrocatalytic and photocatalytic routes to ammonia are reviewed, the catalytic systems are compared and their potential for meeting the likely demand and cost for ammonia considered.


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