One-Step Synthesis of Cellulosed-Based Nitrogen-Doped Carbon Aerogel and Its CO₂ Adsorption Performance

Abstract

CO2 capture and storage (CCS) from point sources is an important part of CO2 emission reduction technologies. In particular, adsorbents with high capacity and selectivity are needed to reduce the cost of CCS technologies. Herein, we report the controlled synthesis of N-doped carbon materials, which exhibit high CO2/N2 selectivity and CO2 adsorption capacity. Specifically, cellulose-based nitrogen-doped carbon aerogels (CNCAs) were prepared using cellulose as a precursor and dissolving it in the mixed solution of NaOH and urea, followed by hydrothermal polymerization, freeze-drying, carbonization and activation. During the experiment, the effects of NaOH and urea on the formation and microstructure of carbon aerogels (CAs) were tested, and the impacts of carbonization/activation temperature on the pore structure, nitrogen content, microcrystalline structure and CO2 adsorption performance were further investigated. Impressively, for a simulated flue gas with a composition of 15% vol of CO2 and 85% vol of N2, the CNCA-750 adsorbent prepared in this work showed excellent adsorption and separation performance for CO2. The adsorption capacity can reach 3.65 mmol CO2/g and that selectivity can reach 19.69. Compared with other absorbents, it has excellent water resistance, high chemical stability, low cost and lower adsorption heat. Comprehensively, CNCAs have great prospects in the ultralow emission of industrial flue gas.