Ca-Embedded C₂N: an efficient adsorbent for CO₂ capture

Abstract

Carbon dioxide as a greenhouse gas causes severe impacts on the environment, whereas it is also a necessary chemical feedstock that can be converted into carbon-based fuels via electrochemical reduction. To efficiently and reversibly capture CO, it is important to find novel materials for a good balance between adsorption and desorption. In this study, we performed first-principles calculations and grand canonical Monte Carlo (GCMC) simulations, to systematically study metal-embedded carbon nitride (CN) nanosheets for CO capture. Our first-principles results indicated that Ca atoms can be uniformly trapped in the cavity center of CN structure, while the transition metals (Sc, Ti, V, Cr, Mn, Fe, Co) are favorably embedded in the sites off the center of the cavity. The determined maximum number of CO molecules with strong physisorption showed that Ca-embedded CN monolayer is the most promising CO adsorbent among all considered metal-embedded materials. Moreover, GCMC simulations revealed that at room temperature the gravimetric density for CO adsorbed on Ca-embedded CN reached 50 wt% at 30 bar and 23 wt% at 1 bar, higher than other layered materials, thus providing a satisfactory system for the CO capture and utilization.

Computational Study on Metal-Ion-Decorated Prismane Molecules for Selective Adsorption of CO2 from Flue Gas Mixtures

“… 4 Recently, metal-ion doping is used as a strategy for improving the gas adsorption capacity of materials. 20 , 25 , 32 , 33 Many molecular systems have been examined for hydrogen adsorption such as metal-decorated benzene, cyclohexane, adamantane, cyclopropane systems, and B- and N-substituted carbon rings. 34 − 36 Such molecular systems can be altered with appropriate modifications or decorated with metal ions for the use of flue gas separation.…”

“…The literature report reveals that the potassium tethering with a carbon matrix can increase the CO 2 capturing capacity from the flue gas mixture. 4 Calcium embedding on the C 2 N structure adsorbs CO 2 more uniformly than other transition metals such as Sc, Ti, V, Cr, Mn, Fe, and Co. 24 Lithium-ion doping has been widely used to improve the CO 2 adsorption capacity of MOFs, 22 phosphorene, 25 lithium silicate, 23 etc. We have exploited the Li + -, K + -, Mg 2+ -, and Ca 2+ -ion-decorated prismane molecules for the selective adsorption capability of flue gas molecules.…”

CO2 Activation and Capture on a Si-Doped h-BN Sheet: Insight into the Local Bonding Effect of Single Si Sites

“…However, other molecules of the gas mixture, such as water vapor and nitrogen, often share the same adsorption sites with CO 2 , which may reduce the CO 2 selectivity seriously. , Besides, the relatively weak interaction between traditional solid adsorbents and CO 2 also limits the selectivity toward the CO 2 capture. Accordingly, some functionalized solid adsorbents with CO 2 chemisorption sites have been investigated for CO 2 capture and separation. − Most recently, two-dimensional (2D) nanomaterials, for their large specific surface areas and adjustable adsorption sites, have drawn extensive research interest. − …”

Photocatalytic potentiality of a two‐dimensional Fe‐doped C 2 N material in visible light

“…Very recently, Zhang et al [17] used MO 2 @C 2 N to exhibit the reduction of N 2 to NH 3 with a maximum free energy change of 0.41 eV and an energy barrier of 0.51 eV. Liu et al [18] performed DFT calculations and Grand Canonical Monte Carlo [19, 20] simulations, to systematically study metal‐embedded carbon nitride (C 2 N) nanosheets for CO 2 capture. He et al [21] claimed that an Fe‐embedded C 2 N monolayer as a promising single‐atom catalyst for CO oxidation by O 2 has been investigated based on DFT calculations.…”