Multiscale analysis of CO2 adsorption mechanisms on porous carbon: An investigation into the impact of intrinsic defects and pore size.

Porous carbon adsorption represents a critical component of CCUS technologies, with microporous structures playing an essential role in CO2 capture. The preparation of porous carbon introduces intrinsic defects, making it essential to consider both pore size and these defects for a comprehensive understanding of the CO2 adsorption mechanism. This study investigates the mechanisms of CO2 adsorption influenced by intrinsic defects and pore size using multiscale methods, incorporating experimental validation, Grand Canonical Monte Carlo simulations, and Density Functional Theory simulations. Intrinsic defects increase structural disorder and microporous content in porous carbon by distorting the graphene framework, thereby creating additional spaces for CO2 adsorption. Moreover, atomic charge redistribution induced by intrinsic defects disrupts the balance of van der Waals and electrostatic potentials, generating more active adsorption sites and enhancing the strength of CO2 adsorption. This research aims to clarify the facilitative mechanisms of intrinsic defects and pore size on CO2 adsorption in porous carbons and to provide a theoretical basis for designing efficient carbon-based adsorbents.