Formulation of porous hetero-frameworks via incorporating poly(ionic liquid)s with porphyrin derivative-functionalized organosilicas for boosting in-situ CO2 capture and conversion

Abstract

Chemical utilization of CO2 has garnered significant attention in response to the growing environmental and energy challenges. Novel porous hetero-frameworks, Zn-TPMOx@PIL-Cn, are developed herein via in-situ polymerization of [VImCn]Br (n = 2, 4, 6) onto porphyrin derivative-functionalized organosilicas (Zn-TPMOx, x = 10, 15, 20). The structures of Zn-TPMOx@PIL-Cn are characterized and found to possess high specific surface area as well as multiple active sites including Lewis acid/base groups, dual hydrogen bond donors and nucleophilic groups. These hetero-frameworks are then utilized for the synthesis of cyclic carbonates through in-situ capture and conversion of CO2 from simulated flue gas. The catalytic performance of different Zn-TPMOx@PIL-Cn and technological conditions are investigated, revealing that the optimal Zn-TPMO20@PIL-C6 catalyst achieves a 96 % yield of chloropropene carbonate with 99 % selectivity under reaction conditions of 110 °C, 1 MPa flue gas for 6 h. Through an assessment of the recyclability and versatility of Zn-TPMO20@PIL-C6 catalyst, it is observed that the robust Zn-TPMO20@PIL-C6 maintains its high activity even after five cycles. Furthermore, this catalyst exhibits satisfactory performance in promoting reactions between various epoxides and flue gas CO2. Based on the synergistic activation of multiple active sites, the cycloaddition mechanism between CO2 and epoxide under the catalysis of Zn-TPMOx@PIL-Cn is proposed.