Nitrogen production

Catalyst
http://citizensciencequarterly.com/2011/05/liquid-nitrogen-generator/

http://homemadeliquidnitrogen.com/joulethomson.html

http://hackaday.com/2014/05/23/homemade-liquid-nitrogen/

https://cen.acs.org/synthesis/One-step-synthesis-urea-green/98/i24?utm_source=YMAL&utm_medium=YMAL&utm_campaign=CEN&utm_content=pos2

https://phys.org/news/2019-04-ammonia-production.html catalyst is extracted with electricity.

Energy
Nitrogen uses 10kwh for one kg of nitrogen in the Faber Bosch process.

links
Air Engine