# Making ammonia: Haber–Bosch on iron versus lithium-mediated electrosynthesis

> Two roads from nitrogen to ammonia drawn as a fork that rejoins: the Haber–Bosch process on a promoted iron catalyst at about 700 K and 100 atm, fed with hydrogen from natural gas, and lithium-mediated electrochemical nitrogen reduction at room temperature and 1 bar, where plated lithium splits N₂ and a proton shuttle turns the nitride into ammonia. A comparison of the two sits inside the fork.

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- Updated: 2026-10-14
- Category: Graphical abstracts
- Method: Graphical abstract
- Starting materials: Nitrogen from the air and hydrogen (from natural gas, or from H₂ oxidation or water with renewable power)
- Product: Ammonia for fertilizer and as a carbon-free fuel
- Key result: Haber–Bosch ~700 K, ~100 atm, 1.9 t CO₂/t NH₃, 1–2% of world energy, 2500 t/day per plant, 150 Mt in 2017 (Chen et al. 2018); Li-mediated ~100% efficiency (Du et al. 2022), 61 ± 1% at 1 bar in flow (Fu et al. 2023), 300 h continuous (Li et al. 2024)
- Figure: 1920 × 1080 px, 89 editable layers (4 generated objects with settings)

## Steps

1. **Haber–Bosch: hydrogen**: Usually from natural gas: about 1.9 t CO₂ per t NH₃; the process takes 1–2% of the world’s annual energy (Chen et al. 2018)
2. **Haber–Bosch: iron**: Iron promoted with Al₂O₃ and potassium, at ~700 K and ~100 atm; one plant makes about 2500 t NH₃ a day (Chen et al. 2018)
3. **Lithium: plate and split**: Li⁺ is reduced to lithium metal, which dissociates N₂ into a nitride (Nguyen et al. 2026; Kim et al. 2017)
4. **Lithium: protonate**: A proton shuttle turns the nitride into NH₃ and frees Li⁺ (Suryanto et al. 2021); a concentrated imide electrolyte gives close to 100% current-to-ammonia efficiency (Du et al. 2022)
5. **Lithium: run continuously**: 25 cm² flow cells at 1 bar coupling N₂ reduction to H₂ oxidation (Fu et al. 2023), 300 h at room temperature (Li et al. 2024)

## Uses

- Graphical abstracts on green ammonia and nitrogen reduction
- Talks comparing thermocatalytic and electrochemical nitrogen fixation
- Teaching the Haber–Bosch process

## References

1. Chen et al., “Beyond fossil fuel-driven nitrogen transformations”, Science 2018. https://doi.org/10.1126/science.aar6611 (review)
2. Du et al., “Electroreduction of nitrogen with almost 100% current-to-ammonia efficiency”, Nature 2022. https://doi.org/10.1038/s41586-022-05108-y (primary)
3. Suryanto et al., “Nitrogen reduction to ammonia at high efficiency and rates based on a phosphonium proton shuttle”, Science 2021. https://doi.org/10.1126/science.abg2371 (primary)
4. Fu et al., “Continuous-flow electrosynthesis of ammonia by nitrogen reduction and hydrogen oxidation”, Science 2023. https://doi.org/10.1126/science.adf4403 (primary)
5. Li et al., “Long-term continuous ammonia electrosynthesis”, Nature 2024. https://doi.org/10.1038/s41586-024-07276-5 (primary)
6. Nguyen et al., “Pathways to sustainable lithium-mediated ammonia electrosynthesis: tuning reaction environment and advancing reactor design”, RSC Adv. 2026. https://doi.org/10.1039/d6ra02156e (review)
7. Kim et al., “Electrochemical synthesis of ammonia from water and nitrogen: a lithium-mediated approach using lithium-ion conducting glass ceramics”, ChemSusChem 2017. https://doi.org/10.1002/cssc.201701975 (primary)

Credit: Drawn by LabCanvas after Chen et al., Science 2018 (doi:10.1126/science.aar6611); Du et al., Nature 2022 (doi:10.1038/s41586-022-05108-y); Suryanto et al., Science 2021 (doi:10.1126/science.abg2371); Fu et al., Science 2023 (doi:10.1126/science.adf4403); Li et al., Nature 2024 (doi:10.1038/s41586-024-07276-5).

## Questions

**What does the “Making ammonia: Haber–Bosch on iron versus lithium-mediated electrosynthesis” template show?** Two roads from nitrogen to ammonia drawn as a fork that rejoins: the Haber–Bosch process on a promoted iron catalyst at about 700 K and 100 atm, fed with hydrogen from natural gas, and lithium-mediated electrochemical nitrogen reduction at room temperature and 1 bar, where plated lithium splits N₂ and a proton shuttle turns the nitride into ammonia. A comparison of the two sits inside the fork.

**What are the steps shown in “Making ammonia: Haber–Bosch on iron versus lithium-mediated electrosynthesis”?** 1. Haber–Bosch: hydrogen: Usually from natural gas: about 1.9 t CO₂ per t NH₃; the process takes 1–2% of the world’s annual energy (Chen et al. 2018). 2. Haber–Bosch: iron: Iron promoted with Al₂O₃ and potassium, at ~700 K and ~100 atm; one plant makes about 2500 t NH₃ a day (Chen et al. 2018). 3. Lithium: plate and split: Li⁺ is reduced to lithium metal, which dissociates N₂ into a nitride (Nguyen et al. 2026; Kim et al. 2017). 4. Lithium: protonate: A proton shuttle turns the nitride into NH₃ and frees Li⁺ (Suryanto et al. 2021); a concentrated imide electrolyte gives close to 100% current-to-ammonia efficiency (Du et al. 2022). 5. Lithium: run continuously: 25 cm² flow cells at 1 bar coupling N₂ reduction to H₂ oxidation (Fu et al. 2023), 300 h at room temperature (Li et al. 2024).

**What are the starting materials and the product?** Starting materials: Nitrogen from the air and hydrogen (from natural gas, or from H₂ oxidation or water with renewable power). Product: Ammonia for fertilizer and as a carbon-free fuel.

**Which papers is “Making ammonia: Haber–Bosch on iron versus lithium-mediated electrosynthesis” based on?** Chen et al., “Beyond fossil fuel-driven nitrogen transformations”, Science 2018 (doi:10.1126/science.aar6611); Du et al., “Electroreduction of nitrogen with almost 100% current-to-ammonia efficiency”, Nature 2022 (doi:10.1038/s41586-022-05108-y); Suryanto et al., “Nitrogen reduction to ammonia at high efficiency and rates based on a phosphonium proton shuttle”, Science 2021 (doi:10.1126/science.abg2371); Fu et al., “Continuous-flow electrosynthesis of ammonia by nitrogen reduction and hydrogen oxidation”, Science 2023 (doi:10.1126/science.adf4403); Li et al., “Long-term continuous ammonia electrosynthesis”, Nature 2024 (doi:10.1038/s41586-024-07276-5); Nguyen et al., “Pathways to sustainable lithium-mediated ammonia electrosynthesis: tuning reaction environment and advancing reactor design”, RSC Adv. 2026 (doi:10.1039/d6ra02156e); Kim et al., “Electrochemical synthesis of ammonia from water and nitrogen: a lithium-mediated approach using lithium-ion conducting glass ceramics”, ChemSusChem 2017 (doi:10.1002/cssc.201701975).

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