Responses
Response to
Du, HL., Chatti, M., Hodgetts, R.Y. et al. Electroreduction of nitrogen at almost 100% current-to-ammonia efficiency. Nature (2022). https://doi.org/10.1038/s41586-022-05108-y https://www.nature.com/articles/s41586-022-05108-y
This could be a breakthrough for fertilizer. Electricity could convert nitrogen gas (N2) to ammonia (NH3) at nearly 100% efficiency - unlike any previous attempts. Lithium is a catalyst for the reaction.
Questions left to answer:
The hydrogen atoms can come from water, I assume? Or does it require hydrogen gas as an input?
How much lithium would be needed (per unit of ammonia output rate)?
- Some clues: the article mentions "stabilised ammonia yield rates of 150±20 nmol s-1 cm-2" but that's per unit of electrode surface area. The lithium is in the electrolyte, not the electrodes.
What would be the lifespan of the system? How would it eventually wear out? At that point, how hard would it be to re-use the lithium in new construction of the same system?
Are there any other catalysts involved? Do the electrodes have to be made of rare metals, for example? How expensive are all the reagents involved (per unit of ammonia output rate)?
Best case scenario:
Farmers could produce all their ammonia fertilizer locally, powered by solar panels. The amount of land needed for solar panels would be quite low:
(This estimate assumes the chemistry equation: 6 H2O + 2 N2 → 4 NH3 + 3 O2)
www.statista.com › Chemicals & Resources › Chemical Industry
Using data from 2021
www.ohio.edu › thermo › property_tables › combustion › Enth_Formation
www.ohio.edu › thermo › property_tables › combustion › Enth_Formation
https://www.newport.com/t/introduction-to-solar-radiation
http://www.ftexploring.com/solar-energy/insolation.htm
In other words, the average farmer could produce enough ammonia using solar panels on just 0.0087% of their farm land. (calculation loading) (calculation loading)