Metallosurfactant Ionogels in Imidazolium and Protic Ionic Liquids as Precursors To Synthesize Nanoceria as Catalase Mimetics for the Catalytic Decomposition of H 2 O 2 .

The gelation behavior of cationic surfactants with different counterions, Br- , [FeCl3 Br]- , and [CeCl3 Br]- , in imidazolium ionic liquids (ILs) and protic ethylammonium nitrate was investigated. Small-angle X-ray scattering measurements and freeze-fracture transmission electron microscopy observations revealed the lamellar phases of metallosurfactant ionogels. The characteristics of imidazolium ILs, including the size and type, have effects on metallosurfactant ionogel properties, such as transformation temperatures, interlayer spacing, and mechanical strength. Cubic fluorite structured cerium oxide nanoparticles (CeO2 NPs) were produced by using metallosurfactant ionogels as precursors. Cubic fluorite CeO2 exhibited good catalase mimetic activity toward H2 O2 to generate O2 , providing more multiple mimetic enzyme activities of CeO2 NPs for H2 O2 .