Ionic Porous Aromatic Frameworks Embedding Polyoxometalates for Heterogeneous Catalysis

Abstract

Porous aromatic frameworks (PAFs) are promising functional porous solids known for their feasible amenability and extraordinary stability. When the framework modified by ionic functional groups, the given ionic PAFs (iPAFs) exhibited charged channels for adsorption, separation and catalysis. However, the surface areas of ionic porous frameworks are usually lower than the neutral ones, and their synthesis limited by specific strategies and complex modifying processes. To overcome these problems, we proposed an intuitive route to construct ionic porous framework with high specific surface area, through a multivariable synthesis strategy. Herein, multivariate ionic porous aromatic framework (MTV‐iPAFs) material named PAF‐270 was synthesized from readily available building units with ionic functional groups. PAF‐270 exhibited hierarchical structure with the highest specific surface area among reported imidazolium functionalized PAFs. Leveraging its physical and chemical properties, we explored its availability for polyoxometalates loading and heterogeneous catalysis. PAF‐270 exhibited high adsorption capacity up to 50% for both H3O40PW12 (HPW) and (NH4)5H6PV8Mo4O40 (V8). HPW@PAF‐270 and V8@PAF‐270 exhibited excellent catalytic abilities for oleic acid esterification and extractive oxidative desulfurization, respectively. Due to the stability of PAFs, these materials also showed remarkable resistance to temperature and pH changes. These results highlight the potential application of MTV‐iPAFs as functional porous materials.