https://phys.org/news/2018-07-borophene-boundaries-barrierresearchers-atom-thick-boron.html

The research led by Rice materials theorist Boris Yakobson and Northwestern materials scientist Mark Hersam appears in Nature Materials.

Borophene differs from graphene and other 2-D materials in an important way: It doesn't appear in nature. When graphene was discovered, it was famously yanked from a piece of graphite with Scotch tape. But semiconducting bulk boron doesn't have layers, so all borophene is synthetic.