Exceptional Gas Adsorption Properties by Nitrogen-Doped Porous Carbons Derived from Benzimidazole-Linked Polymers

Abstract

Heteroatom-doped porous carbons are emerging as platforms for use in a wide range of applications including catalysis, energy storage, and gas separation or storage, among others. The use of high activation temperatures and heteroatom multiple-source precursors remain great challenges, and this study aims to addresses both issues. A series of highly porous N-doped carbon (CPC) materials was successfully synthesized by chemical activation of benzimidazole-linked polymers (BILPs) followed by thermolysis under argon. The high temperature synthesized CPC-700 reaches surface area and pore volume as high as 3240 m2 g–1 and 1.51 cm3 g–1, respectively, while low temperature activated CPC-550 exhibits the highest ultramicropore volume of 0.35 cm3 g–1. The controlled activation process endows CPCs with diverse textural properties, adjustable nitrogen content (1–8 wt %), and remarkable gas sorption properties. In particular, exceptionally high CO2 uptake capacities of 5.8 mmol g–1 (1.0 bar) and 2.1 mmol g–1 (0.15 bar) at ambient temperature were obtained for materials prepared at 550 °C due to a combination of a high level of N-doping and ultramicroporosity. Furthermore, CPCs prepared at higher temperatures exhibit remarkable total uptake for CO2 (25.7 mmol g–1 at 298 K and 30 bar) and CH4 (20.5 mmol g–1 at 298 K and 65 bar) as a result of higher total micropores and small mesopores volume. Interestingly, the N sites within the imidazole rings of BILPs are intrinsically located in pyrrolic/pyridinic positions typically found in N-doped carbons. Therefore, the chemical and physical transformation of BILPs into CPCs is thermodynamically favored and saves significant amounts of energy that would otherwise be consumed during carbonization processes.

Tunable Polyaniline‐Based Porous Carbon with Ultrahigh Surface Area for CO2 Capture at Elevated Pressure

“…[10] It has been reported that the high-pressure CO 2 capacity largely correlates to the pore volumes of micro-and narrow mesopores. [12,23] As was shown in the previous sections, the SU-AC materials possess large pore volumes in the pore size regime below 4 nm (Figure 2c), which indicates their potential for high-pressure CO 2 capture applications. Figure 3a shows the CO 2 total adsorption isotherms of the SU-AC materials at 25 °C and 0-50 bar (see the Supporting Information for definitions of total and excess adsorption).…”

“…It can be seen that the total CO 2 uptake of SU-AC-400 at 30 bar (28.3 mmol g −1 ) is superior to those of the previously reported carbon materials. [10][11][12][23][24][25] Table 2 lists the CO 2 and CH 4 adsorption uptakes and CO 2 /CH 4 selectivities for the SU-AC samples. Table 3 summarizes the textual properties and high-pressure CO 2 capacities of SU-AC-400 in comparison with previously reported carbons.…”

“…[32] A-rNPC 2580 1.09 25.2 21.1 (40 °C) Jalilov et al [24] CPC-700 3242 1.51 25.7 -Ashourirad et al [23] HPC5b2-1100 2734 5.23 27.4 20. 4 Srinivas et al [12] SU [34,35] The significant decrease in Q st with increasing CO 2 loading reveals the heterogeneous nature of the adsorption sites.…”

The CO2 Storage Capacity of the Intercalated Diaminoalkane Graphene Oxides: A Combination of Experimental and Simulation Studies

“…6, CO2 uptake of IGO-n changes gradually from I-to IItype isotherms for n = 4, 8, and 12. Unlike low-pressure uptake which is mostly governed by ultramicropores, large micropores and narrow mesopores are the predominant attributes for attaining high storage capacities at elevated pressures [30,33]. With the increase of interlayer spacing and decrease of oxygen-containing groups for IGO-n, n = 4, 8, and 12, the amount of large micropores and narrow mesopores may increase, leading to a larger increase of CO 2 uptake for IGO-12 than both IGO-4 and IGO-8.…”

Synthesis, characterization and evaluation of porous polybenzimidazole materials for CO2 adsorption at high pressures

“…Polymer based high performance membrane system utilizing various types of polymers as efficient adsorbent and porous polymer networks (PPNs) embedded with bases such as polyamines are fascinating materials and they have high efficiency and improved selectivity for CO 2 , though, very high post synthetic production cost is the major hindrance for the large scale applications of these materials (Lu et al 2012). Studies on polybenzimidazole (PBI) structures and their potential applications in both gas storage and separation have also been reported (Rabbani and El-Kaderi 2012a, b;Ashourirad et al 2015;Sekizkardes et al 2014).…”