Modification of advanced low-dimensional nanomaterials towards high performance CO₂ adsorption: an interpretative state-of-the-art review

Carbon capture continues to gain attention from researchers especially in light of alarming increase of greenhouse gases in the atmosphere in the recent decades. Among the available carbon capture technologies, both of physical and chemical adsorption is favourably seen with various applicable adsorbents successfully introduced. Such promising CO2 adsorbent candidates include low-dimensional nanomaterials such as graphene, carbon nanotubes (CNTs) and fairly new MXenes. In this review, we will be covering the effects of various types of modifications and functionalization of these materials in enhancing the CO2 adsorption capacities. This includes functionalization with oxygenated and protic functional groups, heteroatoms doping, defect engineering and surface modification. It is observed that doping of graphene, amine-functionalization of CNTs and surface termination modification of MXenes are some of the most widely researched strategies. Since MXenes are a recent addition in the field of CO2 capture, we also covered some fundamental theoretical findings to introduce this new 2D nanomaterial to the readers. With this review, we aim to provide a better understanding on how modifications and functionalization process help to improve CO2 uptake in order to help synthesis of high-performance adsorbents in the future.