Solvent-free one-step simple synthesis of N, O-doped microporous carbon using K2CO3 as an activation agent and their application to CO2 capture: Synergistic effect of pore structure and nitrogen–oxygen functional groups

Preparing N, O-doped microporous carbons requires a multi-step process, which is expensive and time-consuming. The preparation methods presented in this work are easy, solvent-free, and more sustainable, using sugarcane bagasse as a carbon precursor, melamine as a nitrogen source, potassium carbonate as an activator, and carbonization at a low temperature. The prepared carbons (BMK-1) showed the highest CO₂ adsorption performance (3.24 mmol/g at 25°C and 4.90 mmol/g at 0°C, 1 bar). An in-depth study was performed to analyze the influence of narrow micropores with different pore ranges and nitrogen–oxygen atoms doping on CO₂ adsorption performance. GCMC simulations and weak interaction analyses showed that a pore size of approximately 0.7 nm is suitable for CO₂ adsorption. The existence of nitrogen–oxygen groups enhanced the Van der Waal interaction between samples and CO₂ molecules. It showed that the pore structure and nitrogen–oxygen group are synergistic factors contributing to CO₂ adsorption properties.