Design of carbonized unidirectional polyimide aerogel for CO2 capture: Effect of pore morphology/topology on CO2 capture

Abstract

Design of efficient CO2 adsorbent is an effective way to capture CO2. Bamboo-derived activated carbon is a promising CO2 adsorbent. Inspired by this, carbonized unidirectional polyimide (CUPI) aerogels were newly designed by the ice templating method using directional freezing technology. The pore property of CUPI aerogel can be tuned by changing the solidification velocity, and a series of CUPI aerogels were designed to explore the CO2 capture performance in view of pore morphology/topology. As a result, the obtained CUPI-8 exhibits higher CO2 adsorption capacity compared to carbonized polyimide aerogels due to the synergistic effect of micropores and lamellar pores. Specially, the CO2 adsorption capacity over CUPI-8 can be up to 5.75 mmol/g at 20 bar and 298 K. Furthermore, the adsorption isotherm of CUPI-8 still shows an upward trend even nearly 20 bar. The isosteric adsorption heat (Qst) value of CUPI-8 is nearly in the ideal scope of 30–50 kJ mol−1. The efficient CO2 adsorption performance and good chemical stability of CUPI aerogel makes it a promising absorbent for practical application. This work provides a new opportunity for researching the effect of pore morphology/topology and the synergistic effect of hierarchical pores on CO2 capture.