In the Rice U article on the manufacture of hematene, which is basically a 2D phase of hematite with similarities to graphene, the process turns out to be surprisingly low tech.
That is the claim - and we can imagine why calcining the powder does not work as well. It misses the purpose of getting flakes of 2D powder. Using ultrasound and electrolysis, it should be much easier to make an activated catalyst via exfoliation, as is done with graphene. This allows potassium carbonate to be used as the electrolyte and possibly remain in the powder without washing it out. It also allows painting the catalyst onto a support. https://www.nature.com/articles/s41565-018-0134-y The doi number is 10.1038/s41565-018-0134-y And notably they perform exfoliation using ultrasound of an electrolyte, which lifts platelets of the desired 2D material and provides far more surface area. This is claimed to be doable with an electrolysis. It is not clear if some supplies of hematite are preferred over others – and that seems to be the case. It is likely that a hexagonal geometry will be seen in the hematene.
