Covalent Organic Frameworks as a Promising Adsorbent for CO Adsorption

Climate change has become a matter of concern these days, mainly due to the increasing anthropogenic activities occurring around us that harm the environment and eventually endanger life on Earth. Among the various pollutants, CO emissions play a vital role in global warming and cause climate change fluctuations. According to studies, in the year 2023, CO emissions rose by 1.1% and reached 37.4 g/t. Therefore, this is the right time to think about carbon capture, conversion, and utilization technologies to mitigate the effects of climate change. It is believed that adsorption-based carbon dioxide capture has the ability to reduce CO pollutants in the atmosphere. Physiosorption techniques are preferred in comparison to chemisorption because physiosorption offers environmental safety. Over the years, many adsorbent materials have been studied for CO adsorption, but among them, COFs represent promising properties such as increased surface area, higher stability, tunable pore size, good recyclability, and most importantly, they have enormous CO capture and selection capability. COFs are divided into 2D and 3D on the basis of the spatial dimensional arrangement of their framework, while on the basis of linkage types, they are categorized into imine, boroxine, hydrazone, azine, etc. The type of linkage chosen depends upon the application. Literature shows that the triarylazine-derived COFs, which have imine linkages in their framework, have proven to be ideal adsorbent materials for CO adsorption, and the proficiency of the material increases with the increasing triarylamine content within the material.