Cobalt-modified MCM-41 catalysts with multiple acidic sites for energy-efficient CO2 desorption of functionalized ionic liquid absorbents

Ionic liquids (ILs) show great application potentials in CO 2 capture due to extremely low vapor pressures, tunable structures, and strong CO 2 affinity. Up to date, many efforts have been focused on the design and absorption performance of novel functionalized ILs, rather than desorption performance. In our previous work, the IL solvent [Cho][Triz]/TMS exhibited exceptional CO 2 absorption performance. As a successive study on decreasing regeneration energy consumption, this work focused on the design and synthesis of novel metal-modified MCM-41 catalysts with multiple acidic sites to enhance CO 2 catalytic desorption in the nonaqueous [Cho][Triz]/TMS (80 wt%/20 wt%) absorbent under lower temperatures. Among all the composite MCM-41 catalysts, the CoM-1/4 catalyst exhibits superior catalytic performance because of the increase of Brønsted acid sites by 232.3 % and Lewis acid sites by 56.2 % compared with pristine MCM-41, which promote CO 2 desorption by accelerating C-N bond breaking. The CO 2 desorption rate and amount increased by 180.2 % and 95.7 %, and the activation energy reduced by 46.7 % compared to the non-catalysis. Therefore, the theoretical regeneration energy consumption of the catalyst-added system was 0.88 GJ/t CO 2 , representing a 76.7 % reduction compared with the 30 wt% MEA solution. Furthermore, the CoM-1/4 catalyst maintained high catalytic activity after 20 cycles. This work indicated that the CoM-1/4 catalyst effectively enhanced the regeneration performance of IL absorbent, facilitating the development of an energy-efficient CO 2 capture process for industrial applications.