Charge‐ and Electric‐Field‐Controlled Switchable Carbon Dioxide Capture and Gas Separation on a C₂N Monolayer

Abstract

The use of advanced materials with a high selectivity and easy regeneration to capture CO2 from a gas mixture is an effective strategy to reduce the greenhouse effect. In this study, we report a comprehensive investigation of CO2, N2, CH4, and H2 adsorption on a C2N monolayer by using DFT calculations. We find that CO2 is adsorbed weakly on a neutral C2N monolayer, and the interaction between CO2 and C2N can be enhanced considerably by applying a negative charge or an external electric field to C2N. Moreover, once the charge state/electric field is switched off, CO2 is released spontaneously from the C2N. However, in contrast to the adsorption of CO2, the interaction between N2/CH4/H2 and C2N is physisorption under all of the above conditions. In all, our study demonstrates that the C2N monolayer can be used as an excellent material for highly selective and reversible CO2 capture and gas separation through the strategy of switching on/off its charge state/electric field. In addition, as a 2 D material, the C2N monolayer possesses a narrow band gap (1.70 eV) that ensures that the application of a charge/electric field can be realized easily experimentally by electrochemical methods.

SiC3 as a Charge-Regulated Material for CO2 Capture

“…Many 2D materials, due to their high surface area for CO 2 capture, have been synthesized or theoretically predicted [7], such as BN 2 [8], CN [9], C 2 N [10], C 3 N [11,12], PC n [13], and Me-N-C (Me = Fe, Cu, Co, etc.) nanosheets [14,15], borophene nanosheet [16,17], covalent triazine frameworks [18], nanoporous grapheme [19], and penta-graphene [20].…”

“…Adding/removing the electrons to/from the adsorbent materials allows alteration of the affinity between the adsorbent materials and gases that is in favor of the CO 2 capture from the gas mixture [21]. Qin et al [10] showed that the interaction between CO 2 and the C 2 N nanosheet is enhanced by the negative charges or external electric field, and CO 2 molecules are released from the C 2 N nanosheet once the charge state/electric field is switched off. Li et al [11] found that CO 2 molecules can be adsorbed and desorbed from the C 3 N nanosheet by adjustment of the applying charge density.…”

Borophene: A Metal‐free and Metallic Electrocatalyst for Efficient Converting CO2 into CH4

“…This is usually because most of the metal‐free materials have poor electronic conductivities and cannot efficiently activate CO 2 , indicating high overpotentials for CO 2 reduction. For example, previous reports have proved that the metal free nanomaterials, such as hexagonal boron nitride, carbon nitride materials can only form weak interaction with CO 2 and cannot effectively active the insert CO 2 . However, metal‐free catalysts possess many advantages, such as low cost, environmental friendly, long durability and they are normally can't be affected by poisoning and crossover effects.…”

“…For example, previous reports have proved that the metal free nanomaterials, such as hexagonal boron nitride, carbon nitride materials can only form weak interaction with CO 2 and cannot effectively active the insert CO 2 . [22][23][24][25] However, metal-free catalysts possess many advantages, such as low cost, environmental friendly, long durability and they are normally can't be affected by poisoning and crossover effects. So, developing novel metal-free catalysts with highly electronic conductivities and high activities for ECRs is greatly necessary.…”

Density functional theory investigation of the enhanced adsorption mechanism and potential catalytic activity for formaldehyde degradation on Al-decorated C2N monolayer

“…For example, Zhu et al [27] prepared C2N for the adsorption of He atoms. Liu et al [28] reported that Ca-embedded C2N is an efficient adsorbent for CO2 capture, while Qin et al [29] employed charge and electric field effects to control CO2 capture and gas separation on a C2N monolayer. Furthermore, in the context of targeting gas pollution, Bhattachayya et al [30] showed that a C2N monolayer can efficiently trap HF, HCN, and H2S pollutants, causing different changes in the I-V characteristics of the monolayer, which is a promising feature for the detection of the corresponding gases.…”