Nitrogen and Oxygen Codoped Porous Carbon with Superior CO₂ Adsorption Performance: A Combined Experimental and DFT Calculation Study

Abstract

Nitrogen and oxygen codoped porous carbons (NOCKs) were obtained by nitrogenization, preoxidation, and chemical activation. Considering the activation reagent amount and modification temperature, the pore structure conducive to CO 2 adsorption was obtained. NOCK-400-1 exhibits maximum CO 2 capacity of 6.77 mmol g −1 at 0 °C and 4.46 mmol g −1 at 25 °C, 1 bar. It also presents high dynamic CO 2 adsorption capacity under 15% CO 2 /85% N 2 at ambient temperature and excellent adsorption regenerability. The results show that the improvement of CO 2 adsorption performance is mainly due to the synergistic effect of codoping nitrogen and oxygen. The codoping method effectively improves the relative contents of pyrrolic-N, pyridinic-N, and phenolic hydroxyl with promoting the synthesis of amorphous carbon. Furthermore, the codoping method enhances the porosity of NOCKs with less consumption of KOH. The density functional theory (DFT) calculations also demonstrate two kinds of van der Waals actions (namely, dispersion interaction and electrostatic attraction) for CO 2 adsorption on the nitrogen and oxygen codoped carbon surface. Additionally, the physical adsorption mechanism on the heterogeneous surface of adsorbents is confirmed by adsorption isotherm and thermodynamic study. Therefore, nitrogen and oxygen codoped porous carbons are a promising sorbent for CO 2 capture, which provides the effective information for carbon design.

Impacts of Organic Structures and Inherent Minerals of Coal on Soot Formation during Pyrolysis

“…As can be seen from the figure, with the increase of A 4 value, the value of soot/(soot+tar) and C/H decreases, that is, the conversion rate of tar to soot decreases. The oxygen-containing functional groups in coal will vaporize at high temperatures to form oxygen-containing substance during pyrolysis, which will inhibit the formation of soot by reforming reaction [52,53] or oxidation reaction (oxygen-containing radicals, such as OH and O) [15][16][17]. Therefore, the conversion rate of coal tar to soot is inversely related to the absorption peak areas of oxygen-containing functional groups in the FTIR spectra of coal.…”

Green Synthesis of Pyridyl Conjugated Microporous Polymers as Precursors for Porous Carbon Microspheres for Efficient Electrochemical Energy Storage

“…The C1s corelevel XPS spectra showed three peaks at~284.7,~285.2, and 286.9 eV (Figure 3b,d), which are attributed to C=C, C=N and C=O bonds, respectively. [22,26] The N 2 adsorption/desorption isotherms of NCM23-X and NCM33-X measured at 77.4 K (Figure 4a,c) exhibited type I curves, which are the characteristics of the microporous materials. A sharp increasing in N 2 uptake found at low pressure (p/p 0 < 0.05) also signified the microporosity.…”

“…Full survey XPS spectra of two typical carbons i. e. NCM23‐800 and NCM33‐800 indicate the existence of N, C, and O atoms (Figure S14). The C1s core‐level XPS spectra showed three peaks at ∼284.7, ∼285.2, and ∼286.9 eV (Figure b,d), which are attributed to C=C, C=N and C=O bonds, respectively …”

A diamino-functionalized silsesquioxane pillared graphene oxide for CO2 capture

“…The problematic amine-based and ammonia solutions that have been broadly used until now for CO 2 capture, need to be replaced by sorbents that are low-cost, easy to scale up and that can be regenerated and reused at low energy cost. 2,3 It is well-known that carbon materials such as amorphous carbon, nanotubes, bers and graphite can be used as sorbents/ sieves, [4][5][6][7][8][9] catalytic substrates, 10 membranes, 11 etc. due to their low mass in combination with chemical inertness, thermal stability and mechanical properties.…”