Highly Selective CO₂ Uptake in Novel Fishnet-like Polybenzoxazine-Based Porous Carbon

Abstract

Porous activated carbons are considered to be promising CO2 adsorbents due to their high specific surface area, high chemical stability, and tailorable surface properties. However, their low CO2 capture capacity and inferior CO2/N2 selectivity have hindered their application. Here, we describe novel fishnet-like, polybenzoxazine-based porous carbons (PBZCs) prepared by a single-step monomer thermal curing, carbonization, and activation process. The PBZCs exhibit an ultrahigh CO2 uptake capacity of 8.44 mmol g–1 and a superior CO2/N2 IAST selectivity of 56 (at 273 K, 1 bar). Such excellent CO2 adsorption performance may to some extent be ascribed to a high specific surface area and a large ultramicropore volume. However, the results reveal that the CO2 capture capacity is not solely associated with porosity. It may also be attributable to the abundant hydroxyl groups of the PBZCs, which may form hydrogen bonds with CO2 molecules. The role of the oxygen functionalities of porous carbon for CO2 capture was further demonstrated through theoretical calculation combined with experimental analysis. Hydrogen bonding lowers the binding energy between the carbon framework and CO2 molecules, which greatly facilitates CO2 adsorption. Furthermore, the novel fishnet-like structure can anchor CO2 molecules effectively and selectively. These PBZC carbons are potentially promising CO2 adsorbents.

One‐pot synthesis of high N‐doped porous carbons derived from a N‐rich oil palm biomass residue in low temperature for CO 2 capture

“…Moreover, for OAC‐500‐2.5, the calculated selectivity was 15.7 at 1 bar and mixture (CO 2 : N 2 = 15:85), which was similar or higher to those of N‐doped adsorbents published recently . Because of the difference between N 2 and CO 2 , CO 2 molecules could form hydrogen bonds and react with prepared adsorbent, but there was no strong interaction between N 2 and adsorbents . This resulted in a high CO 2 adsorption and low N 2 adsorption.…”

“…37,38 Because of the difference between N 2 and CO 2 , CO 2 molecules could form hydrogen bonds and react with prepared adsorbent, but there was no strong interaction between N 2 and adsorbents. 39 This resulted in a high CO 2 adsorption and low N 2 adsorption. This large adsorption variation helped to improve the selectivity of CO 2 /N 2 .…”

Advanced Carbon Materials Derived from Polybenzoxazines: A Review

“…Within the past decade, polybenzoxazines have been found to be extremely effective in adsorbing CO 2 from air streams, which is crucial for reducing industrial pollution and weakening the effects of global warming from carbon emissions [37,[106][107][108][109][110][111]. Many studies attributed this ability to the porous qualities of benzoxazine, particularly the micropore volume and BET surface area.…”

“…[37]. While BE in CO2 uptake, it is not as consistently significant as micropo volume and BET surface area are the dominant characteri though there are numerous other factors, including process One of these alternate factors was hypothesized to be hy by Hong et al The presence of hydrogen bonding decrease for CO2 on the active sites in the benzoxazine micropores, effect between the CO2 and benzoxazine [108]. This was also selectivity over N2, as N2 is unable to form as strong interm schemas of the bonding of CO2 can be seen in Figure 42.…”

“…Micropo volume and BET surface area are the dominant characteristics driving CO2 adsorptio though there are numerous other factors, including processes and conditions. One of these alternate factors was hypothesized to be hydrogen bonding, as propose by Hong et al The presence of hydrogen bonding decreases the required binding energ for CO2 on the active sites in the benzoxazine micropores, thus providing an anchorin effect between the CO2 and benzoxazine [108]. This was also said to be the reason for CO selectivity over N2, as N2 is unable to form as strong intermolecular forces [108].…”