Oxygen-containing functional group-facilitated CO2 capture by carbide-derived carbons

Abstract

A series of carbide-derived carbons (CDCs) with different surface oxygen contents were prepared from TiC powder by chlorination and followed by HNO3 oxidation. The CDCs were characterized systematically by a variety of means such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ultimate analysis, energy dispersive spectroscopy, N2 adsorption, and transmission electron microscopy. CO2 adsorption measurements showed that the oxidation process led to an increase in CO2 adsorption capacity of the porous carbons. Structural characterizations indicated that the adsorbability of the CDCs is not directly associated with its microporosity and specific surface area. As evidenced by elemental analysis, X-ray photoelectron spectroscopy, and energy dispersive spectroscopy, the adsorbability of the CDCs has a linear correlation with their surface oxygen content. The adsorption mechanism was studied using quantum chemical calculation. It is found that the introduction of O atoms into the carbon surface facilitates the hydrogen bonding interactions between the carbon surface and CO2 molecules. This new finding demonstrated that not only the basic N-containing groups but also the acidic O-containing groups can enhance the CO2 adsorbability of porous carbon, thus providing a new approach to design porous materials with superior CO2 adsorption capacity.

Thin, High‐Flux, Self‐Standing, Graphene Oxide Membranes for Efficient Hydrogen Separation from Gas Mixtures

“…[18] Upon wetting, as tretching of the GO membranesw as observed, whereas the films becamev ery fragilea nd could not stand for ar elativelyh igh appliedp ressure. [20] However,C O 2 uptake is independento ft he specific surface area and microporous volume of the carbon material, but closely related to the oxygen content. These structural componentsh ave as ignificant impact on thep roperties of the material in terms of surface phenomena.…”

“…[9] On the other hand, vast water vaport ransport through such films can be attributed to wateraccessible nanochannels, formed by the empty interspacing (estimated as % 5 )b etweent he non-oxidizedr egionso fG O monolayered sheet. [19,20] If the porous carbon materials include ah ydroxyl/carboxyl functional group at the surface, this could lead to complex surfacei nteractions that could passivate or enhance specific gas adsorption. The humidity impactso nt he permeation rate of GO films for various penetrants, as confirmed by the XRD analysiso ft he dry/wet state.…”

“…The humidity impactso nt he permeation rate of GO films for various penetrants, as confirmed by the XRD analysiso ft he dry/wet state. [19] Such adsorption-enhancing effect (acid-base interaction mechanism [20] )i sa ttributed to hydrogen-bond interactions between hydrogen atoms on the carbon surfacea nd CO 2 molecules. [18] Furthermore,c omparedw ith graphene, GO contains various oxygen-containing functional groups (e.g.,h ydroxyl,e poxy, carbonyl, carboxyl groups).…”

“…[18] Furthermore,c omparedw ith graphene, GO contains various oxygen-containing functional groups (e.g.,h ydroxyl,e poxy, carbonyl, carboxyl groups). [20] Interestingly,f ew experimentally determined gas permeability and selectivity data for solely self-standingG Og as-separation membranes have been published to date. It is known that the presence of oxygen-containing functional groups can enhancet he CO 2 adsorptionc apacity of porous carbons.…”

CO2 and CH4 Adsorption Behavior of Biomass Based Activated Carbons

“…An increase on the CO 2 adsorption capacity upon the presence of oxygen-containing surface functionalities by means of acid-base interactions and hydrogen bonds formation between the adsorbate and the activated carbons surface [36,37]. The high electronegativities of oxygen surface groups due to electron gain from the carbon surface atoms gives them the possibility of electron-donation with the CO 2 adsorbate molecules acting then as basic groups.…”