Radical Polymerization by Heterogeneous Ceria Nanocatalysts

Heterogeneous catalysts for radical polymerization are desired due to advantageous recyclability, which facilitates further purification and various applications. Herein, colloidal ceria (CeO₂) nanocrystals function as an efficient heterogeneous catalyst driving radical polymerization of methyl methacrylate (MMA). Enrichment of Ce³⁺ is observed on the CeO₂ surface upon polymerization, revealing a surface-mediated redox mechanism underpinned by the reversible formation of oxygen defects. The heterogeneous polymerization pathway is further extended to the preparation of SiO₂-grafted-PMMA particle brushes, which demonstrates the potential to access polymeric composite materials. The study provides an effective heterogeneous route to catalyzing radical polymerization that has been routinely realized with homogeneous catalysis. A wider scope of reducible metal oxides is anticipated to be explored, where compelling recyclability and tunable reactivities can be attained.