Amine-Functionalized SiC nanowires aerogel synchronizes high capacity and ultra-rapid kinetics for CO₂ capture

CO₂ capture can mitigate carbon emissions with the objective of achieving carbon neutrality. Solid amine adsorbents have emerged as one of the most promising materials for capturing CO₂. However, balancing the diffusion and adsorption of CO₂ remains a significant challenge, making it difficult to achieve high capacity and rapid kinetics simultaneously. In this study, SiC nanowires aerogel (SiCNWA) was functionalized with tetraethylenepentamine (TEPA) and diethanolamine (DEA) for CO₂ capture. The optimal adsorbent was synthesized with a total amine loading of 90 wt%, comprising 75 wt% TEPA and 25 wt% DEA. It exhibits a high CO₂ adsorption capacity of 4.71 mmol/g and ultra-rapid adsorption kinetics, achieving 80 % adsorption capacity within the first minute. The advantageous properties stem from the synergistic effects arising from the unique three-dimensional network structure of SiCNWA, coupled with the complementary group interactions of the hybrid amines. The ultra-high porosity of aerogel facilitates a high proportion of amine loading and dispersion, contributing to its high CO₂ adsorption capacity. Additionally, the continuous network structure offers efficient channels for CO₂ transport, enabling ultra-rapid CO₂ adsorption kinetics. The high amine density of TEPA provides abundant adsorption sites for CO₂, and the addition of DEA can effectively mitigate the aggregation and deactivation of amine groups, thereby significantly improving the adsorption rate and adsorption capacity. This aerogel-hybrid amines strategy effectively balances diffusion and adsorption, offering valuable insights for advancing aerogel-based materials for CO₂ capture.