Fabricating self-templated and N-doped hierarchical porous carbon spheres via microfluidic strategy for enhanced CO2 capture

Abstract

N-doped porous biochar is a promising material for CO2 capture due to its easy regeneration and high CO2 selectivity. In this study, a new strategy was proposed to design monodisperse porous carbon spheres by microfluidics system with chitosan in-situ grow ZIF-8, utilizing ZIF-8 as a self-sacrificing template and nitrogen dopant. The mesoporous volume and N content of carbon spheres can be adjusted through the ZIF-8 content in the microfluidic system and carbonization temperature, within 0.01 ∼ 0.48 cm3/g and 3.23 ∼ 19.25%, respectively. The optimum sample (CZ2-900) exhibited superior CO2/N2 selectivity at 40. Adsorption kinetics and diffusion resistance indicated that CO2 adsorption in CZ2-900 is controlled by the process of CO2 diffusion from the surface of the basic site to mesopores. This was the first attempt at using a microfluid chip to grow ZIF-8 in chitosan skeleton and pyrolysis approach to synthesize N-doped porous carbon sphere where both additional template agent and activator are non-used, revealing the potential of microfluidic technology for the precise synthesis of highly selective CO2 capture materials.