(7a) White Graphene As a Novel Type of Adsorbent

Boron nitride nanosheets (BNNSs) are 2D flat nanosheets consisting of an equimolar ratio of sp²-bonded B and N atoms. Despite the structural similarity to graphene (hence the name “white graphene”), BNNSs exhibit unique properties, such as an enhanced thermal and chemical robustness. It is a highly porous material, with a theoretical surface area of ~2640 m² g^-1 for one sheet, which makes it an excellent candidate for adsorption applications. However, controlling the synthesis of porous BNNSs is not trivial and the synthesis mechanisms remain unclear. If these were unveiled, one could tune the structure of BNNSs to target specific separation applications.

This study investigates the synthesis mechanisms of BNNSs via a bottom-up approach (i.e. synthesis from chemical precursors rather than via exfoliation). Specifically, the effects of the reaction parameters on the chemical and physical features of the resulting BNNSs are analyzed using a range of analytical techniques (e.g. N₂ sorption, XRD, FT-IR, Raman, NMR, thermogravimetric analysis). The findings highlight the role of the reaction intermediate on the resulting porous BNNSs (S_BET > 1,000 m² g^-1) as well the key parameters controlling its structure and chemistry. Preliminary gas adsorption tests (including CO₂ capture) indicate the promising role of BNNSs as a robust adsorbent.