From Molecular Precursors to Nanoparticles—Tailoring the Adsorption Properties of Porous Carbon Materials by Controlled Chemical Functionalization

Abstract

Nanoporous carbon materials (NCMs) provide the "function" of high specific surface area and thus have large interface area for interactions with surrounding species, which is of particular importance in applications related to adsorption processes. The strength and mechanism of adsorption depend on the pore architecture of the NCMs. In addition, chemical functionalization can be used to induce changes of electron density and/or electron density distribution in the pore walls, thus further modifying the interactions between carbons and guest species. Typical approaches for functionalization of nanoporous materials with regular atomic construction like porous silica, metal-organic frameworks, or zeolites, cannot be applied to NCMs due to their less defined local atomic construction and abundant defects. Therefore, synthetic strategies that offer a higher degree of control over the process of functionalization are needed. Synthetic approaches for covalent functionalization of NCMs, that is, for the incorporation of heteroatoms into the carbon backbone, are critically reviewed with a special focus on strategies following the concept "from molecules to materials." Approaches for coordinative functionalization with metallic species, and the functionalization by nanocomposite formation between pristine carbon materials and heteroatom-containing carbons, are introduced as well. Particular focus is given to the influences of these functionalizations in adsorption-related applications.

C2N: A Class of Covalent Frameworks with Unique Properties

“…[ 3 ] X‐ray photoelectron spectroscopy (XPS) is a surface analysis technique that provides chemical and electronic state information, making it suitable for characterizing and understanding the local bonding environment of chemical species. [ 107 ] And thermogravimetric analysis (TGA) is carried out to provide first‐hand information to investigate the thermal stability of C 2 N. The C 2 N materials are really noble, and they are hard to oxidize and combust. The oxidation stability could be display in TGA test under air conditions.…”

Carbon-based catalysts for Fischer–Tropsch synthesis

“…Currently, substantial progresses have been made in the methodology to tune the texture structures of carbon-based supports to improve the performance of supported metal catalysts. [228][229][230][231][232][233][234] The extension of Stöber method for the preparation of carbon-based supports opens up new areas of carbon spheres. 235,236 Carbon-based supports impregnated with highly monodispersed metal nanoparticles have been successfully made and applied in catalysis.…”

Recent advances in carbon-based supercapacitors

“…With an increase in the number of comprehensive studies, the self-doping strategy has been recently subdivided into adding a supplementary dopant (e.g., ethanediamine or phosphoric/boric acid) to the carbon precursors before pyrolyzing or the direct pyrolysis of organic salt/polymer precursors assembled by heteroatomcontaining building blocks. 123 The supplementary dopant can not only provide plentiful heteroatoms, but also serve as a catalyst, stabilizer, activator, or structure-directing agent. For example, Jia's group synthesized chitosan-derived N/B-codoped porous carbon nanosheets with three amino acids and boric acid as the N/B source.…”

“…Wang's group demonstrated that the presence of poly(ionic liquid)s was beneficial for optimizing the hydrothermal carbonization of sugar precursors for N-doped porous carbon nanoparticles, wherein the poly(ionic liquid) chains introduced electrostatic repulsion for minimized particle agglomeration and unexpectedly functioned as the pore former and N supply. 125 As an extension of the post-doping strategy, the one-step doping activation is frequently applied via directly calcining the mixtures of carbon precursors and heteroatomdoped activators, 123 and the resultant N-rich microporous carbons activated by NaNH 2 afforded outstanding capacitance of 350.2 F g À1 at 1 A g À1 in 6 M KOH with excellent rate retention of 74.2% at 10 A g À1 . 126 Another desirable route toward fabricating functionalized carbons at a higher doping level is the direct pyrolysis of organic salt/polymer precursors (e.g., metal complexes, conjugated polymer networks, ionic liquids, and poly(ionic liquid)s).…”