Conversion of sodium carboxymethyl cellulose into N-doped porous carbon as efficient CO2 adsorbent

Sodium carboxymethyl cellulose (CMC-Na) is a cellulose derivative, and has extensive applications in different areas. In the current work, we utilized CMC-Na as carbon precursor to prepare N-doped porous carbons as efficient CO 2 adsorbents. CMC-Na was pyrolyzed with K 2 CO 3 and urea, which acted as the activator and nitrogen source, respectively. The obtained carbons exhibited highly porous structure, were successfully doped with nitrogen element. In particular, CMC2U700 demonstrated an impressively high specific surface area of 2564 m 2 /g. Effects of pyrolysis temperature and urea addition on the carbons’ physicochemical properties were studied with details. It was found that urea addition affected the activation process of K 2 CO 3 , and significantly enhanced the carbons’ porosity. A high CO 2 uptake of 18.82 mmol/g was achieved by CMC2U700 at 25 °C and 20 bar. The sample CMC0U800 also demonstrated excellent stability during cyclic adsorption measurements. Relationships between CO 2 adsorption performances and the carbons’ properties were then investigated. It was found that CO 2 uptakes at 1 bar and 20 bar correlated best with ultramicropore volume and specific surface area, respectively. Overall, the present work offers a perfect example for the conversion of CMC-Na into functional carbon materials for the field of carbon neutrality.