
Graphene is inorganic/human-assembled crystalline carbon, laid out flat in 2D sheet, with a hexagonal lattice configuration.
This is copying nature: Bees use hexagonal packing for their honeycombs to maximize space.

Carbon has many forms and uses since it’s one fundamental constituent of our material reality. Like other elements, it’s a type of atom, with a specific particle configuration of electrons orbiting a nucleus of protons and neutrons.
Carbon commonly materializes in metamorphic rock as coal, graphite or diamond. And carbon compounds, such as CO2, are numerous.
One process to arrange carbon as Graphene in mass industrial quantity is “chemical vapor deposition.”(1) Apparently, there are other methods as well — see above video. Among other characteristics a 1 atom thick sheet of graphene is flexible and lightweight, highly conductive and resilient.
Targeted uses include, energy harvesting and storage ie batteries and solar cells, and generally ultra high performing electronics, and ultra-filtration — see the excellent graphic explanation below.

Nanomaterials, microfabricated on the nanometer scale, pose issues for sustainability like other materials. There is also an effort to construct biodegradable nanomaterials, which is necessary for any biomedical applications for non-toxic “biocompatibility” with the human body.
The bigger picture for any material is circularity — whether can it be put to good use and re-used without creating a lot of waste. After all, waste management and modifying systems to reduce it are important and pressing global issue.
It seems entirely possible to make a circular graphene carbon-capture process.
As an investment, Graphene seems promising as an ultra high performing material that can also be tuned for biodegradability. One can also pay attention to source materials and production methods.
1. https://news.mit.edu/2018/manufacturing-graphene-rolls-ultrathin-membranes-0418