MOF-derived bimetallic coordination polymer@cobalt-aluminum layered double hydroxide for highly selective CO2 adsorption: Experiments, mechanisms

• Published in: Journal of colloid and interface science 2023-09, Vol.645, p.784-793
• Main Authors: Huang, Zhen, Ying, Liangri, Gong, Fengchun, Liu, Shule, Wang, Weilong, Ding, Jing
• Format: Article
• Language: English
• Subjects: Adsorption; Carbon dioxide; Coordination polymers; Layered double hydroxide; Metal–organic framework
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.05.039

[Display omitted] •A novel adsorbent (Co-Al-LDH@Hf/Ti-MCP-AS) was prepared by MOF derivatization for the adsorption of CO2.•The novel adsorbent shows a very high selective adsorption capacity and reusability for CO2.•Thru XPS characterization and DFT computational verification, it is shown that the adsorption mechanism is mainly CO2-producing carbamate by acid-base action with adsorbents. Selective capture of CO2 is one of the most effective strategies for combating the greenhouse effect. In this study, we report the synthesis of a novel adsorbent—an amine-based cobalt-aluminum layered hydroxide with a hafnium/titanium metal coordination polymer (denoted as Co-Al-LDH@Hf/Ti-MCP-AS)—through the derivatization of metal–organic frameworks (MOFs) for selective CO2 adsorption and separation. Co-Al-LDH@Hf/Ti-MCP-AS achieved the maximum CO2 adsorption capacity of 2.57 mmol g−1 at 25 °C and 0.1 MPa. The adsorption behavior followed the pseudo-second-order kinetics and Freundlich isotherm models, indicating that chemisorption occurs on a non-homogeneous surface. Co-Al-LDH@Hf/Ti-MCP-AS also exhibited selective CO2 adsorption in CO2/N2 and excellent stability over six adsorption–desorption cycles. An in-depth analysis of the adsorption mechanism through X-ray photoelectron spectroscopy and density-functional theory and frontier molecular orbital calculations revealed that adsorption occurs through acid–base interactions between amine functional groups and CO2 and that the tertiary amines (N3) have the highest affinity toward CO2. Our study provides a novel strategy for designing high-performance adsorbents for CO2 adsorption and separation.