It has nothing to do with clean energy, other than the downstream effects of cheap CNTs should the process be refined enough to scale and commercialize. The hydrogen is recycled in the process. The primary thing that it produces are CNT aerogels. However according to the paper catalyst efficiency is shit. Says less than 0.1% of catalyst particles actually grew CNTs. No wonder CNTs are currently ≥$200/kg. Needs improvement by either dramatically increasing catalyst efficiency or finding dirt cheap iron/sulfur sources.

Carbon fouling is also a major block to scale. 15-20% of carbon deposits as soot on reactor walls. At a 1MW scale thats 15-30 kg/h of crud degrading the catalytic heat transfer. Continuous cleaning or scheduled downtime would drive OPEX out of possible realities.

Hot hydrogen loops are a son-of-a-bitch and equal continuous embrittlement of pipes, valves, pumps. Seals that work at temperature. H2 Leak detection. Some real heavyweight process safety engineering here.

The reactor chemistry is solved. The paper proves it works.

The scale-up is where clean-tech startups go to burn money and die.