Facile synthesis of Ag@CeO₂ core–shell plasmonic photocatalysts with enhanced visible-light photocatalytic performance

Highlights: • Novel Ag@CeO₂ core–shell nanostructures with well-controlled shape and shell thickness were successfully synthesized. • The Ag@CeO₂ showed dramatic photocatalytic activity than pure CeO₂. • Improving activity is from a combination of SPR effect and hybrid effects. • The mechanism was proposed and confirmed by ESR and PL results. - Abstract: Novel Ag@CeO₂ core–shell nanostructures with well-controlled shape and shell thickness were successfully synthesized via a green and facile template-free approach in aqueous solution. As-prepared samples were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflection spectroscopy (DRS), electron spin resonance (ESR) and photoluminescence spectroscopy (PL). The structures with different core shapes and controllable shell thickness exhibited unique optical properties. It is found that the nanoscale Ag@CeO₂ core–shell photocatalysts exhibit significantly enhanced photocatalytic activities in the O₂ evolution and MB dye degradation compared to pure CeO₂ nanoparticals. The enhancement in photocatalytic activities can be ascribed to the localized surface plasmon resonance (SPR) of Ag cores. Moreover, larger active interfacial areas and contact between metal/semiconductor in the core–shell structure facilitate transfer of charge carriers and prolong lifetime of photogenerated electron-hole pairs. It is expected that the Ag@CeO₂ core–shell structure may have great potential in a wider range of light-harvesting applications.