Self-assembled “3D-stereoscopic printing-like” PANI-based porous carbon aerogels for high-efficiency CO₂ adsorption

Adsorption technology is a promising strategy for efficient CO₂ capture, especially when adsorbents feature three-dimensional interconnected pore structures that enable rapid gas transport. Polyaniline (PANI), a nitrogen-rich and cost-effective polymer, holds the potential for CO₂ adsorption. However, strong hydrogen bonding between PANI molecular chains often leads to significant aggregation, hindering dispersion and reducing the density of accessible adsorption sites. In this study, we present an innovative cryo-polymerization approach to fabricate CO₂ adsorbents 3D-(PANI@PAM) gel, where PANI is “self-assembled” onto the surface of a three-dimensional interconnected polyacrylamide (PAM) medium. This method enables the ordered “stereoscopic printing” of PANI on PAM pore surfaces, effectively preventing PANI aggregation. After activation treatment, the resulting nitrogen-rich aerogel exhibits uniform nitrogen distribution and a high nitrogen content. The resulting hierarchical pore structure (0.54–0.64 nm) significantly enhances CO₂ affinity. The optimized aerogel achieves an exceptional CO₂ adsorption capacity of 6.04 mmol·g⁻¹ at 0 °C and 101 kPa, surpassing comparable materials. Furthermore, the aerogel demonstrates a CO₂/N₂ selectivity of 23.07. These findings underscore the unique advantages and significant potential of carbon aerogels in CO₂ capture, providing a novel and effective pathway for designing high-capacity polymer-based carbon materials.