Linear poly(ionic liquid)-adsorbed graphene oxide as a bifunctional catalyst for CO2 conversion

Abstract

In this study, we successfully developed non-covalent graphene oxide-poly(ionic liquid) (GO-PIL) composites through an in situ polymerization approach, wherein linear PIL was polymerized within the interlayered structure of GO. The synthesized composites demonstrated exceptional catalytic efficiency for the cycloaddition of CO₂ with epoxides, surpassing the performance of previously reported covalently immobilized GO-IL catalysts. Particularly, GO-PVimI-2 catalyst exhibited outstanding performance, achieving 98 % conversion of styrene oxide (SO) with nearly perfect selectivity (>99 %) towards the target product under mild reaction conditions (333 K, 1 bar, 20 h). Furthermore, the catalyst displayed excellent recyclability, retaining its catalytic activity over multiple cycles with only a minimal 1 % decrease in SO conversion. The superior catalytic performance was attributed to the synergistic effects between the flexible PIL chains and the abundant hydrogen bond donors in GO, along with stabilizing π-π interactions between the aromatic structure of GO and the imidazolium moieties of PIL. This innovative combination of GO with linear ionic polymers provides a robust and versatile platform for the design of highly efficient and recyclable catalysts, applicable to a wide range of chemical transformations.