Engineering stable TEPA networks within confined pores for efficient CO2 capture

Amine-based sorbents are promising for low-concentration CO 2 capture, yet their practical application has long been hindered by poor stability. In this study, amidated tetraethylenepentamine (TEPA) network (ATN) sorbents were synthesized by crosslinking TEPA with 4 binary organic acids in the molded alumina-silica (MAS) supports. Characterizations confirm the successful formation of amide bonds between the primary amines of TEPA and binary acids within the pore channels, a key innovation that reconfigures TEPA distribution—shifting from a wall-attached state (as in conventional systems) to an aggregated polymeric network. This structural breakthrough yields remarkable stability enhancements: unlike TEPA/MAS, which loses ∼90 % of its initial capacity after 50 cycles, TEPA/MAS- t , t -MA, and TEPA/MAS-FA retain ∼80 % of their capacity under the same conditions. Experimental results and DFT calculations further reveal a novel mechanistic insight: acids containing double bonds form more stable amide networks with stronger p-π conjugation than straight-chain acids. By integrating molecular crosslinking with porous support engineering, this strategy offers a robust framework for designing durable, high-performance CO 2 capture materials for actual applications.