Perforation routes towards practical nano-porous graphene and analogous materials engineering

Nano-perforated graphene sheets have emerged as exciting two-dimensional materials for a broad range of scientific and commercial purposes, due to their modified physicochemical properties as compared to native graphene materials. Nanoporous graphene sheets as a class of two-dimensional materials with thicknesses ranging from sub-nanometre to few tens of nanometres, possess high specific surface areas and porous mesh structures with tuneable porosity levels. These properties lead to high densities of unsaturated carbon edges around the pores, making them attractive candidates for applications such as energy storage, separation, sensing or catalysis. Several perforation methodologies have been reported to sculpt pores across graphene structures via etching or guided growth mechanisms. This review focuses on current and emerging nano-perforation methodologies for the two-dimensional graphene materials, and discusses controllable porosity parameters in terms of physical pore size and surface pore density across 2D materials. The relationship between perforation methodology and the achieved porosity level is also discussed and related to electronic or surface reactivity properties. Suggestions towards perforation methodologies in relation to targeted pore size and density, as well as the current challenges hindering scalability of engineering the nanoporous graphene and other similar two-dimensional materials are also highlighted.