Experimental and Theoretical Investigations into the Performance and Mechanism of CO₂ Capture by 3D and 2D ZnAl Layered Double Hydroxides

Abstract

Two-dimensional (2D) materials have a wide range of applications in adsorption and catalysis because of their high specific surface areas and large number of surface active sites. In this paper, bulk ZnAl layered double hydroxides (ZnAl-LDHs or bulk-LDHs) and 2D monolayer ZnAl-LDHs (monolayer-LDHs) were constructed and used for CO2 capture at temperatures of 298–573 K. The experimental results show that monolayer-LDHs have a large specific surface area (455 m2 g–1) and shows an excellent CO2 capture performance (4.5 mmol g–1). The CO2 adsorption capacity of monolayer-LDHs decreases greatly with an increase of the temperature, while bulk-LDHs are less affected by the temperature. Moreover, the parameters of charge distribution, density of states, and charge transfer of bulk-LDHs and monolayer-LDHs were studied in detail by density functional theory, and the difference of the adsorption mechanism between two LDH materials in CO2 capture was compared. It is found that monolayer-LDHs have better electronic activity than bulk-LDHs. At low temperature, CO2 is more likely to be physically adsorbed on the surface of monolayer-LDHs, and the adsorption process is more likely to occur. CO2 is more easily adsorbed on the surface of bulk-LDHs in the form of chemisorption, the adsorption energy is larger (−1.01 eV), but the CO2 capture capacity is quite stable at high temperature.

Transition-Metal-Doped SiP2 Monolayer for Effective CO2 Capture: A Density Functional Theory Study

“…MXene 2D nanosheets in a mixed-matrix membrane showed good selectivity toward CO 2 and ran with excellent stability over an extended period of time . Similar favorable results for 2D ZnAl and Ni–Al layered double hydroxide nanosheets were found as well. , A variety of methods, such as doping, could also be used to manipulate the capture. Wang et al showed that doping graphene with Cu and Ni increased CO 2 adsorption from weak physisorption to chemisorption .…”

High-Efficiency Photocatalytic Ammonia Synthesis by Facet Orientation-Supported Heterojunction Cu2O@BiOCl[100] Boosted by Double Built-In Electric Fields

“…Catalyst characterization, pNRR, photoelectrochemical measurements, the setting and parameters of the density functional theory are given in the files of Supporting Information, including Figures S1–S4. , …”

Tuning Co2+ Coordination in Cobalt Layered Double Hydroxide Nanosheets via Fe3+ Doping for Efficient Oxygen Evolution

“…Co 3 O 4 , − transition-metal hydroxide, , and non-noble-metal-based compounds have been researched broadly and used in boosting OER. − Among them, as a peculiar transition-metal hydroxide material, transition-metal layered double hydroxide (LDH) has attracted much attention due to its unique layered structure and excellent performance. LDH is a kind of anionic clay material with a layered structure, which has not only the molecular composition of transition-metal hydroxide but also the unique anion intercalation structures. − The general formula for the structure of LDHs is as follows: [ , where M means divalent or trivalent cations (usually Co, Ni, Cu, Fe, and other transition metals) and A means intercalated anions (usually CO 3 2– , COO – , NO 3 – , etc.) .…”