Phosphorus-induced formation of micropores and nitrogen groups for efficient CO2 capture: Experiments and DFT calculations

Due to their outstanding physicochemical characteristics, heteroatom-doped porous carbon materials have attracted significant attention. Herein, the pore structure and N content of the NPC-X material were regulated via P doping using a simple pyrolysis and activation method. The CO2 adsorption mechanism and electronic properties of the materials were determined by combining characterization results and theoretical calculations. Density functional theory calculations show that P has the capability to increase the porosity and facilitate the generation of pyridine-N and pyrrole-N functional groups in N-doped carbon materials. Moreover, the interaction between N groups and CO2 can be effectively elucidated through the analytical density of states. The experimental results show that the NPC-2 sample exhibits excellent CO2 adsorption performance (4.50 mmol/g at 298 K and 1 bar) and recycling stability. This study presents new synthetic approaches for the preparing N/P codoped carbon materials and explores the CO2 adsorption mechanism of materials with multiple coexisting functionalities.