Atomically dispersed lewis acid sites meet poly(ionic liquid)s networks for solvent-free and co-catalyst-free conversion of CO2 to cyclic carbonates

Abstract

The rational integration of multiple functional units into heterogeneous materials to improve catalytic performance is highly desirable for CO2 value-added processes. Herein, a catalyst composed of porous carbon matrix with atomically dispersed Lewis acid sites (i.e., AlO5 motifs) and imidazolium-based poly(ionic liquid)s (denoted as PILs@Al-O-C) was fabricated. Compared with pure Al-O-C or PILs, the optimized PILs@Al-O-C exhibits superior catalytic performance (>90% yield) towards cycloaddition reaction of CO2 and epoxides in the absence of solvent and co-catalyst. The enhanced activity of PILs@Al-O-C is attributed to the synergistic effect among the uniform N sites (Lewis base sites) and abundant bromide anions (nucleophilic agents) in the PILs network, as well as the atomically dispersed Al sites (Lewis acid sites) in the Al-O-C matrix. This work provides an advanced PILs@Al-O-C catalyst for constructing a neat catalytic system towards CO2 fixation.