Constructing Hierarchically Porous N-Doped Carbons Derived from Poly(ionic liquids) with the Multifunctional Fe-Based Template for CO₂ Adsorption

Abstract

Nitrogen-doped hierarchical porous carbons with a rich pore structure were prepared via direct carbonization of the poly(ionic liquid) (PIL)/potassium ferricyanide compound. Thereinto, the bisvinylimidazolium-based PIL was a desirable carbon source, and potassium ferricyanide as a multifunctional Fe-based template, could not only serve as the pore-forming agent, including metallic components (Fe and Fe 3 C), potassium ions (etching carbon framework during carbonization), and gas generated during the pyrolysis process, but also introduce the N atoms to porous carbons, which were in favor of CO 2 capture. Moreover, the hierarchically porous carbon NDPC-1-800 (NDPC, nitrogen-doped porous carbon) had taken advantage of the highest specific surface area, exhibiting an excellent CO 2 adsorption capacity and selectivity compared with NDC-800 (NDC, nitrogen-doped carbon) directly carbonized from the pure PIL. Furthermore, its hierarchical porous architectures played an important part in the process of CO 2 capture, which was described briefly as follows: the synergistic effect of mesopores and micropores could accelerate the CO 2 molecules’ transportation and storage. Meanwhile, the appropriate microporous size distribution of NDPC-1-800 was conducive to enhancing CO 2 /N 2 selectivity. This study was intended to open up a new pathway for designing N-doped porous carbons combining both PILs and the multifunctional Fe-based template potassium ferricyanide with wonderful gas adsorption and separation performance.

Carbon Dioxide Capture through Physical and Chemical Adsorption Using Porous Carbon Materials: A Review

“…PET is the most widely used carbon precursor among these polymers due to its wide availability and high carbon content [3]. Poly-ionic liquids (PIL) are also being actively utilized as a potential polymer-based carbon precursor for synthesizing adsorbents [157,158]. The PILs possess high thermal stability (even up to 400 • C), are rich in heteroatoms (e.g., nitrogen), and produce a higher yield of the adsorbent compared to other polymeric precursors [157][158][159].…”

“…A hierarchically porous structure is generally more favorable for adsorbing the CO 2 molecules [158]. Although the narrow micropores are more beneficial than large-sized micropores for CO 2 adsorption (stronger adsorbate-adsorbent interactions) [4,101,188], the mesoporous and microporous structure in a particular adsorbent plays a vital role in improving the mass transfer of CO 2 molecules.…”

“…Although the narrow micropores are more beneficial than large-sized micropores for CO 2 adsorption (stronger adsorbate-adsorbent interactions) [4,101,188], the mesoporous and microporous structure in a particular adsorbent plays a vital role in improving the mass transfer of CO 2 molecules. The mesopores also act as a passage for the CO 2 molecules to reach the micropores [25,135,144,158]. Besides, the fraction of micropore volume, shape, and size distribution are the critical factors to be controlled during the synthesis of carbon-based adsorbents [25,146].…”

Simple fabrication of a phosphorus‐doped hierarchical porous carbon via soft‐template method for efficient CO2capture

“…PILs based on bisvinylimidazolium salts were ideal carbon sources, and potassium ferricyanide, with a versatile iron‐based formwork, served as a porogenic agent, with metal components, potassium ions, and gases generated during pyrolysis, and introduced nitrogen atoms to facilitate CO 2 capture. The results showed that NDPC‐1‐800 had better CO 2 adsorption volume and selectivity than NDC‐800, which was directly carbonized from pure PIL 25 . Recently, N‐doped carbon as a metal‐free, low‐cost electrocatalyst for CO 2 RRs has received increasing attention in academic and industrial fields 26 …”

“…The results showed that NDPC-1-800 had better CO 2 adsorption volume and selectivity than NDC-800, which was directly carbonized from pure PIL. 25 Recently, N-doped carbon as a metalfree, low-cost electrocatalyst for CO 2 RRs has received increasing attention in academic and industrial fields. 26 Compared with research on nitrogen-doped carbons, there are few studies and literature reports on phosphorus-doped carbons.…”