CH3COOK Etching to Prepare N-Doped Peanut Shell Microporous Carbon for Efficient CO2 Adsorption

This study successfully synthesized microporous nitrogen-doped biomass porous carbon (NPSCs) through a two-step method, utilizing cost-effective peanut shells as the carbon source, urea as the nitrogen source, and CH3COOK as the activating agent. By optimizing the ratio of the activating agent and the carbonization temperature, the pore structure and surface chemical properties of the NPSCs were effectively tailored. Characterization results revealed that the NPSCs exhibited a significant number of micropores, attributed to the critical etching effect of CH3COOK. The optimal sample, NPSC-2-700, demonstrated a specific surface area of 1455.41 m2/g and a micropore volume of 0.57 cm3/g. Notably, NPSC-2-700 achieved remarkable CO2 adsorption capacities of 3.91 and 5.90 mmol/g at 25 and 0 °C, respectively, under 1 bar. Additionally, NPSC-2-700 maintained exceptional adsorption performance even after ten consecutive CO2 adsorption–desorption cycles. The selectivity was calculated to be 43 using the ideal solution adsorption theory in a classic gas mixture (CO2/N2 = 15 vol %:85 vol %), demonstrating good dynamic CO2 capture capacity. These findings underscore the promising potential of nitrogen-doped microporous carbon materials for efficient carbon capture applications.