Porous architectures with a high strength‐to‐weight ratio, large surface area, and high resilience have recently garnered interest for applications in gas storage, battery electrodes, and fuel cells. These materials’ desired properties can be achieved by tuning pore characteristics, such as wall thickness, pore size, and pore directionality, and by using various constituent materials. Another important application of such materials is carbon dioxide capture, which helps mitigate global warming caused by rising atmospheric CO 2 levels. In this study, a hierarchical structure with controlled pore direction was fabricated through directional freeze‐casting using different types of bio‐nanofibers from nature, such as cellulose, chitin, or chitosan. These free‐standing structures with controlled pore orientation were then pyrolyzed at 700°C, resulting in free‐standing carbon with controlled pore direction. The carbonized structure made from chitosan nanofiber demonstrated a CO 2 capture performance up to 13 times higher than its powder‐type counterpart, with stable cyclability.
Kim et al. (Sun,) studied this question.