Facile Carbonization of Microporous Organic Polymers into Hierarchically Porous Carbons Targeted for Effective CO₂ Uptake at Low Pressures

Abstract

The advent of microporous organic polymers (MOPs) has delivered great potential in gas storage and separation (CCS). However, the presence of only micropores in these polymers often imposes diffusion limitations, which has resulted in the low utilization of MOPs in CCS. Herein, facile chemical activation of the single microporous organic polymers (MOPs) resulted in a series of hierarchically porous carbons with hierarchically meso-microporous structures and high CO2 uptake capacities at low pressures. The MOPs precursors (termed as MOP-7-10) with a simple narrow micropore structure obtained in this work possess moderate apparent BET surface areas ranging from 479 to 819 m(2) g(-1). By comparing different activating agents for the carbonization of these MOPs matrials, we found the optimized carbon matrials MOPs-C activated by KOH show unique hierarchically porous structures with a significant expansion of dominant pore size from micropores to mesopores, whereas their microporosity is also significantly improved, which was evidenced by a significant increase in the micropore volume (from 0.27 to 0.68 cm(3) g(-1)). This maybe related to the collapse and the structural rearrangement of the polymer farmeworks resulted from the activation of the activating agent KOH at high temperature. The as-made hierarchically porous carbons MOPs-C show an obvious increase in the BET surface area (from 819 to 1824 m(2) g(-1)). And the unique hierarchically porous structures of MOPs-C significantly contributed to the enhancement of the CO2 capture capacities, which are up to 214 mg g(-1) (at 273 K and 1 bar) and 52 mg g(-1) (at 273 K and 0.15 bar), superior to those of the most known MOPs and porous carbons. The high physicochemical stabilities and appropriate isosteric adsorption heats as well as high CO2/N2 ideal selectivities endow these hierarchically porous carbon materials great potential in gas sorption and separation.

Water‐Resistant and Transparent Plastic Films from Functionalizable Organic Polymers: Coordination Polymers as Templates for Solid‐State [2+2]‐Photopolymerization

“…The polyethylene family accounts for more than 80 % of plastic films that are used in day‐to‐day activities. Several polyamide thin films are effective in applications for the capture of CO 2 from industrial gases to prevent global warming . For food packaging and medical purposes, the gas permeability of the plastic film is an important aspect because passage of oxygen is required to keep the contents fresh.…”

“…Several polyamide thin films are effective in applicationsf or the capture of CO 2 from industrial gases to prevent global warming. [22] For food packaging and medicalp urposes, the gas permeability of the plastic film is an important aspect because passage of oxygen is required to keept he contentsf resh. To obtain plastic films with ac ombination of some of these features, we designed an ew diene molecule that contains amide moieties, pyridine units as sidearms, andf lexible aromatic spacers such as p-xylyl between 3-pyridyl acryl amide moieties (Scheme 1).…”

Evaluation of the BET Theory for the Characterization of Meso and Microporous MOFs

“…The BET method can be used for the characterization of various types of microporous materials including zeolites, photocatalysts, polymers, and photoelectrodes . Since MOFs can contain different sizes of micropores, from “ultramicropores” (below 7 Å) to bigger “super‐micropores” (between 7 and 20 Å) or even mesopores (above 20 Å), the obtained BET surface areas can potentially be inaccurate.…”

POSS‐Based Nitrogen‐Doped Hierarchically Porous Carbon as Metal‐Free Oxidation Catalyst

“…Consistent with previous reports, the nitrogen content found by elemental analysis (2.7 wt%) is much lower than the expected (9.1 wt%). It can be explained by a) competitive Scholl homocoupling reaction between OPS where a porous homo polymer (HPP‐2) can be obtained solely from OPS under the reaction conditions (Figure S2 and Table S1); b) incomplete reaction between chloride and phenyl groups, which can be proved by the residual Cl content (2.32 wt.%) in the final product; c) residual unconsumed starting materials or solvents embedded in the porous networks, especially in the closed pores, which are difficult to remove completely even after exhaustive Soxhlet extraction. The Al content remaining in the networks was negligible as proved by inductively coupled plasma (ICP) analysis.…”

“…Moreover, the nitrogen content decreased from 2.7 wt% (HPP) to ca. 1.5 wt% (N‐HPC−T) during the carbonization process, consistent with previous reports . After etching, it increases to ca.…”