Trace Carbon Dioxide Capture by Metal-Organic Frameworks

Climate deterioration is closely related to the CO2 concentration in the atmosphere, which is considered one of the major environmental challenges we are facing today. It is urgent to take immediate actions to prevent further climate change. In comparison with postcombustion CO2 capture technologies from flue gas, trace CO2 capture directly from air is still a challenge but very important for both CO2 control in the atmosphere and air quality control in confined space. This review highlights recent research advances in the use of metal organic frameworks (MOFs) for trace CO2 capture, with the emphasis on employing amine-functionalized MOFs and ultramicroporous MOFs. Herein, the reported strategies to enhance CO2 adsorption capacity and selectivity by MOFs are categorized into three main directions, including the developments of MOFs with open metal sites, ultramicroporous MOFs, and amine-functionalized MOFs. The mechanisms combined with trace CO2 capture performance by these MOFs are discussed in detail, offering some promising adsorption solutions for future practical applications of MOF materials. In addition, the performance for CO2 capture under humid conditions and the regenerability of these MOF adsorbents are revealed. In order to address major issues of capacity, selectivity, and stability especially under humid conditions, precise construction and engineering of MOFs to achieve the optimized porous materials are needed.