Mechanistic understanding of oxidation of graphitic lattice for gaining control over the incorporation of Å-scale pores in graphene

Porous two-dimensional (2D) selective layer hosting zero-dimensional pores is attractive for molecular differentiation because one can tune molecular selectivity (by tuning pore size) and molecular flux (by tuning pore density). Porous graphene is an attractive candidate for this given that single-layer graphene can be conveniently synthesized in single-layer polycrystalline film morphology by chemical vapor deposition. Several promising results towards molecular separation have been demonstrated by incorporating pores in graphene by a variety of methods including physical etching (bombarding lattice with energetic beams) and oxidative etching. <br/><br/>In this presentation, I will highlight the important role of oxidative etching of graphene in highly scalable and easy-to-implement porosity incorporation in graphene with excellent control in the incorporation of Å-scale pores. I will discuss our recent efforts in understanding the mechanism of incorporation of these pores in the graphene lattice, starting with a single oxidation event, followed by cooperative assembly of the chemisorbed oxygen (epoxy) into clusters which then regulate the final pore size. I will discuss how clusters have ordered superlattice of O (against expectations of amorphous structure), which then leads to a series of sequences resulting in the incorporation of pores. I will discuss further examples of oxidation reactions that allow one to tune the size of pores in a highly controllable manner. Finally, I will discuss recent activities in scaling up graphene membranes, thanks to a highly scalable graphene oxidation chemistry.