Preparation of porous carbons based on polyvinylidene fluoride for CO2 adsorption: A combined experimental and computational study

• Effects of carbonization temperature on polyvinylidene fluoride were investigated.
• Narrow micropores (<0.7 nm) were mainly developed during carbonization.
• The highest CO2 uptakes were 5.27 mol kg−1 at 0 °C and 3.59 mol kg−1 at 25 °C.
• Repeated adsorption–desorption cycles maintained initial CO2 adsorption capacity.
• DFT calculation showed that fluorine removal from carbons favors CO2 adsorption.

Microporous carbons were developed for CO2 capture from polyvinylidene fluoride (PVDF) via a simple carbonization method. The carbonization was carried out in the temperature range of 400–800 °C, and the effects of the carbonization temperature on the characteristics and CO2 adsorption behavior of the prepared carbon materials were investigated by both experiments and density functional theory studies. The textural characteristics of the carbon materials were highly dependent on the carbonization temperature, and narrow micropores (<0.7 nm) were predominantly generated from the decomposition of PVDF giving off fluorine during carbonization. The specific surface area and pore volume increased up to 1011 m2 g−1 and 0.416 cm3 g−1, respectively, and the highest CO2 adsorption capacity of 3.59 mol kg−1 was obtained at 25 °C and ∼1 bar in PVDF carbonized at 800 °C. The carbonized PVDFs also exhibited highly stable CO2 adsorption uptake and rapid kinetics through repeated adsorption–desorption cycles, showing that carbonized PVDFs are promising adsorbents for CO2 capture. The density functional theory calculation suggested that stable configuration with favorable adsorption energy can be introduced by the removal of fluorine from PVDF, which results in the reduction of repulsive interactions between electronegative fluorine in PVDF and oxygen in CO2 molecule.

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