Comment by hansvm
2 days ago
Like you said, the energy comes from somewhere. If I had to guess, it's effectively solar powered (the catalyst lowering the activation energy enough that photons can actually do the work), plus indirectly solar powered in that you need wind to physically move the compounds around.
I have read the research paper and the energy appears to come mostly from the pump, because the flow of gas and vapor in the device causes contact electrification, which helps the redox reaction.
They have not given any numbers about the energy consumed by the pump, but at least in this experimental devices it is likely that the amount of ammonia that is produced is very small for the energy consumed by the pump, in comparison with other synthesis methods.
For now, the ammonia is produced as a solution in water with very low ammonia concentration. Perhaps this could be usable directly as a fertilizer for plants. For any other uses, concentrating the ammonia produced in this way would require a large amount of additional energy.
In the form presented now, this method of ammonia synthesis would be too inefficient, but the authors hope that the efficiency can be improved some orders of magnitude.