Porous carbon based on polyvinylidene fluoride: Enhancement of CO₂ adsorption by physical activation

Global warming has become a crucial issue and various efforts have been made to mitigate the emission of CO₂, the most dominant greenhouse gas. Adsorption is considered a promising technology for CO₂ capture, and carbon materials are good candidates for CO₂ adsorption. In this study, highly porous carbons were prepared from polyvinylidene fluoride by single-step physical activation under CO₂ flow at temperatures of 700-950°C. The effect of activation temperature on the characteristics and CO₂ adsorption properties of the prepared porous carbons was studied. Additionally, the dependence of CO₂ adsorption capacity on various textural properties was investigated to identify the most important factor that determines CO₂ adsorption. Both surface area and pore volume increased proportionally with activation temperature because of the newly produced pores and enlarged pore size within the carbon. Additionally, CO₂ adsorption is highly dependent on the volume of pores that are below 0.70 nm in size. Among the samples tested, the porous carbon prepared at 800°C exhibited maximum CO₂ adsorption capacities of 6.05 and 3.84 mol kg^-1 at 0 and 25°C, respectively, besides showing good CO₂/N₂ selectivity, excellent recyclability, easy regeneration, and rapid adsorption-desorption kinetics.