N-doped activated carbon derived from furfuryl alcohol - development of porosity, properties, and adsorption of carbon dioxide and ethene

In this study, N-doped activated carbon was obtained through physical activation from a polyfurfuryl alcohol mixed with urea. The immediate attention was paid to porous structure influencing CO2 and C2H4 uptakes by the investigated materials. Because of these adsorbates' kinetic diameters, research on the shifting of dominating pore size to wider diameters during the activation process was of particular interest. The obtained materials were characterized by XPS, XRD, TGA, and volumetric adsorption method of N-2 and CO2 at 77 K at 273 K, respectively. The highest adsorption capacity of C2H4 at 303 K was measured for a sample with the highest specific surface area. This correlated well with the volume of pores with a diameter up to 1.0 nm. On the other hand, the highest uptake of CO2 was measured for relatively low specific surface area material. Compared to other studied materials, it resulted from the considerably higher volume of pores with diameters up to 0.8 nm and 0.7 nm, which are the most affecting CO2 adsorption at 273 K and 303 K, respectively. XPS analysis confirmed the presence of nitrogen and oxygen functional groups on the surfaces of carbons prepared. To determine pore size favoring efficient CO2 and C2H4 uptakes by the carbons, adsorption isobars at 1025 hPa were measured for both gases.