In the 70's I saw one of those science films about oxygen and was impressed at the demo involving a stream of pure o2 and lighting an iron wool pad... that promptly burned like tissue paper in a wind storm.

50 years later some bright boffins have come up with a way to make iron dust a carbon free fuel source; burning this dust results in iron oxide. You know... RUST.

This article does a good job explaining the benefits and challenges:

#Green #DivestFossilFuels

https://spectrum.ieee.org/iron-fuel