Ionic liquid-assisted preparation of Ag-CeO₂ nanocomposites and their improved photocatalytic activity

As a good stabilizer, [BMIM]BF₄ ionic liquid (IL) has been successfully utilized to assist preparation of Ag nanoparticles (NPs) decorated on CeO₂ supports. The obtained IL-stabilized Ag-CeO₂ nanocomposite showed better photocatalytic degradation activity (92%) of Auramine O (AO) dye as compared with pure CeO₂ (35%) NPs and IL-free Ag-CeO₂ (65%) nanocomposite after 90 min of visible light irradiation. The improvement could be attributable to small size (5 nm) of IL-stabilized Ag NPs loaded on the surface of CeO₂ supports and the large surface area of its nanocomposite (11.11 m²/g). These increase in the interfacial contact areas between IL-stabilized Ag NPs and CeO₂ supports that enhance the charge transfer and reduce the recombination of the photogenerated electron-hole pairs. Further, the IL-stabilized Ag-CeO₂ nanocomposite showed good photocatalytic stability for dye degradation. The persuasible mechanism of enhanced photocatalytic degradation of AO was clearly discussed on the basis of localized surface plasmon resonance (LSPR) effect of Ag NPs as well. Accordingly, this work can pave new pathway to prepare nanoparticles coated on metal oxide nanostructures for the practical applications.