Scalable confined-space microwave heating strategy enables the rapid preparation of N/O co-doped activated carbons with high gas capture capacity

Abstract

Heteroatom doping is essential for enhancing the performance of activated carbons (ACs) in various environmental-related applications. Herein, a scalable confined-space microwave heating (CSMH) strategy is proposed and demonstrated to achieve minute-level fast preparation of N/O co-doping ACs with well-developed porosity. The introduction of confined space prevents the escape of nitrogenous and oxygenous volatiles, enabling the sufficient reaction for heteroatom doping. Therefore, the nitrogen content of MWC-0.5 (6.0 at.%) is higher than that of MW-0.5 (3.5 at.%) and CH-0.5 (4.3 at.%). This causes a nearly 50 % reduction in the consumption of nitrogenous reagents. Moreover, through CSMH strategy, N/O co-doped ACs (6.0 at% and 8.1 at% for N and O, respectively) with high pore volume (0.53 cm3 g−1) can be acquired to achieve an excellent adsorption performance for toluene (0.31 g g−1) and CO2 (3.97 mmol g−1 at 25 °C and 1 bar) and outstanding CO2/N2 selectivity (189 at 0.02 bar). This work for the first time develops a scalable confined-space N/O co-doped strategy for enhancing the chemical activity of ACs with low-spend nitrogenous reagents.