Foaming Effect of a Polymer Precursor with a Low N Content on Fabrication of N-Doped Porous Carbons for CO₂ Capture

Because of their sufficient surface areas, developed porosities, and high stabilities, N-doped porous carbons (NDPCs) have presented an excellent CO₂ adsorption ability. NDPCs are usually fabricated through the carbonization of N-containing polymers. The effect of N species enlarging surface areas and foaming pores has been confirmed. However, traditional polymer precursors of NDPCs must have a relatively high N content and give unsatisfactory structural characters and CO₂ capacities of their NDPCs. In this study, an NDPC precursor code-named NUT-50-EDA with a N content of only 6.4 wt % is prepared, while the amino groups in the precursor still play a significant role in the porogen during the carbonization process. The generated NDPCs show more abundant micropores, larger surface areas, and higher CO₂ adsorption capacities compared to those of the counterpart porous carbons (PCs) made from the precursor without ammonification. With a relatively low N content (1.5 wt %), NDPC-700 with a large surface area of 1620 m²/g, obtained by carbonization treatment of NUT-50-EDA at 700 °C, still displays an outstanding CO₂ uptake of 6.4 mmol/g at 0 °C and 1 bar, compared with other reported benchmarks. This work demonstrates that NUT-50-EDA, possessing a highly effective pore-foaming agent of N species, can be utilized as the ideal precursor for improving the porosities and CO₂ capacities of its NDPCs.