Importance of Pore Structure and Surface Chemistry in Carbon Dioxide Adsorption on Electrospun Carbon Nanofibers

Abstract

The development of carbon dioxide (CO 2) capture technology is of great urgency for reducing the emission of CO 2 to the atmosphere and mitigating global warming. Polyacrylonitrilebased electrospun carbon nanofibers were prepared in this study at different carbonization temperatures for CO 2 capture. The effects of the primary surface features and the functional groups of the carbon nanofibers on CO 2 adsorption capacity were discussed. Results showed that the carbonization temperature influenced the porous texture and the surface chemical states of the carbon nanofibers significantly. The specific surface area, total pore volume, and micropore volume of the fibers increased with increasing carbonization temperature, but the ultra-micropore volume presented a different trend. The samples carbonized at 750 °C had the smallest average pore hydraulic radius. Moreover, in the micropore range, the volume of sub-micropores increased at a greater rate than that of ultra-micropores after activation. The carbonization temperature was also of great importance in controlling the nitrogen content and composition. A CO 2 uptake of 3.47 mmol/g at 25 °C and 1 atm was achieved. The ultramicropore volume of the carbon nanofibers was the most important parameter for determining CO 2 uptake at 1 atm; however, the CO 2 adsorption capacity at 0.15 atm was highly dependent on the surface pyrrolic or pyridonic groups.

Biomass‐based Self‐single‐oxygen Heteroatom‐doped Hierarchical Porous Carbon Nanosheets for High‐performance Symmetrical Supercapacitors

“…These results were in line with the previous data obtained from the SEM images. In addition, the sub‐micropores observed in all MOAC samples confirmed their potentials as high‐performance energy storage devices [64] …”

“…In addition, the sub-micropores observed in all MOAC samples confirmed their potentials as high-performance energy storage devices. [64] The pyrolyzed MOAC samples subsequently indicated a combination of 3D hierarchical pores, with an average size of approximately 3.19 nm.…”

“…To maintain high capacitance in energy storage electrodes, the sub-micropores (< 1 nm) confirmed at MOAC-ZnCl 2 were found to be essential for biomass waste-based active materials. [8,64] Moreover, the high ultra-micropores (1.0 < x < 2.2 nm) were found to increase the wettability of the active materials, to enhance the absorption of electrolyte ions. [65] To increase maximum utilization, the mesoporous and macropore scales played a good role in providing barrier-free channels in all the 3D directions assisting the transport of electrolyte ions.…”

Isosteric Enthalpy Behavior of CO2 Adsorption on Micro-Mesoporous Materials: Carbon Microfibers (CMFs), SBA-15, and Amine-Functionalized SBA-15

“…At 298 K and 1 bar, CMFs adsorbed 2.32 mmol g −1 , and this is comparable with other studies that synthesized carbon microfibers using PAN as a precursor and the electrospinning method. For example, Chiang et al synthetized carbon nanofibers (CNF) with a specific surface area of 306 m 2 g −1 and an adsorption of 2.52 mmol CO 2 g −1 [33]. Heo et al explored CNF with and without activation, CNF and ACNF, respectively; CNF presented a small area (12 m 2 g −1 ) and small adsorption (0.55 mmol CO 2 g −1 ), while ACNF with area of 925 m 2 g −1 had an adsorption of 2.21 mmol CO 2 g −1 [34].…”

“…h value are those that were carbonized at lower temperatures. Moreover, based on their XPS results, these materials present a higher amount of nitrogen and oxygen, which means that the presence of these groups allows a higher surface affinity between the adsorbate and the adsorbent [33]. Independently of the selected arrangement, the trend in the (∆ ads .…”