Biomass Based N/O Codoped Porous Carbons with Abundant Ultramicropores for Highly Selective CO₂ Adsorption

In this work, N/O codoped porous carbons (NOPCs) were derived from corn silk accompanied by Na2CO3 activation. The porous structures and surface chemical features of as-prepared carbon materials were tailored by adjusting the Na2CO3 mass ratio. After activation, the optimized sample (NOPC1) with abundant ultramicropores and pyrrolic N displays an enhanced CO2 adsorption capacity of 3.15 mmol g(-1) and 1.95 mmol g(-1) at 273 K and 298 K at 1 bar, respectively. Moreover, this sample also exhibited high IAST selectivity (16.9) and Henry's law selectivity (15.6) for CO2/N-2 at 298 K as well as moderate heat adsorption. Significantly, the joint effect between ultramicropore structure and pyrrolic N content was found to govern the CO2 adsorption performance of NOPCs samples.