CUPOLA project

During the two months at Huazhong University of Science and Technology from October to December 2023, we undertook the project titled “Light-Triggered Pore Size Tuning in Photo-switching Covalent Triazine Frameworks for Low Energy CO₂ Capture.” Under the supervision of Professors Wu and Tan, we successfully calculated and characterized a series of azobenzene-functionalized photo-switching PCTFs. Through collaboration with the theoretical calculation chemistry team at Dalian Institute of Chemical Physics, we successfully calculated about the cis-trans transition based on DTF theoretical calculations. Two cis-to-trans transition processes were considered and compared via theoretical calculations, namely, the process from “cis1” to “trans-” configurations, denoted as “Route 1”, and that from “cis1” to “trans2” configurations, denoted as “Route 2”. The changes in Gibbs energy between the initial and final states, as well as the corresponding transition state, were estimated. After UV light irradiation, the azobenzene-functionalized PCTF1 displayed a 5% decrease in CO₂ uptake capacity. However, this value could be doubled either through the structural alleviation method or by tuning the azobenzene content. The CO₂ switching processes of the PCTFs were also successfully repeated three times. Calculation results further explained the not fully recovered recycling process of PCTF2 because of steric hindrance created by a high density of azobenzene units inside the pore channel.