Review on Nitrogen-Doped Porous Carbon Materials for CO₂ Adsorption and Separation: Recent Advances and Outlook

Abstract

One of the most serious environmental problems is the global warming brought by CO2 and other greenhouse gases. Thus, the development of Carbon Capture, Utilization, and Storage Technology (CCUS) is urgent. Thereinto, the merits of porous carbon adsorption materials are their substantial specific surface area, stable physical and chemical properties, adjustable pore structure, etc., and they are considered to be good adsorbents for CO2. The adsorption properties of porous carbon material are capable of being directionally controlled by regulating the collocation of carbonization and activation methods and setting the technological parameters used in the preparation process. In addition, nitrogen doping can enhance the effect between adsorbent and adsorbate, leading to higher CO2 adsorption capacity. After in-depth studies, although there is still no clear explanation on the mechanism of nitrogen-doped enhancement of the adsorption properties of the adsorbent, it can be confirmed that the main reason is not the traditional acid–base theory, but a large number of micropores, specific surface area, and induction forces are more likely to be the root cause. The porous carbon materials preparation methods, pore structure adjustment strategies, and the types of functionalization and mechanism between nitrogen-doped sites and adsorbents are highlighted in this Review. Finally, the future development direction and existing challenges of this emerging field are also discussed.