Near-Infrared Light Manipulated Chemoselective Reductions Enabled by an Upconversional Supersandwich Nanostructure

Core–satellite is one of the most powerful superstructures since it leads to enhanced or completely new properties through compatible combination of each component. Here we create a novel ceria-based core–shell–satellite supersandwich structure with near-infrared (NIR) light manipulated catalytic activity by integrating the upconversion luminescent and catalytic functionality of CeO<sub>2</sub> nanoparticles. Specifically, lanthanide-doped octahedral CeO<sub>2</sub> nanoparticles (o-CeO<sub>2</sub>) are coated with silica layer (o-CeO<sub>2</sub>@SiO<sub>2</sub>) to enhance their luminescence intensity. The pH-dependent catalytic active cubic CeO<sub>2</sub> nanoparticles (c-CeO<sub>2</sub>) are then assembled on the surface of o-CeO<sub>2</sub>@SiO<sub>2</sub> to form the supersandwich structure (o-CeO<sub>2</sub>@SiO<sub>2</sub>@c-CeO<sub>2</sub>) following a classic chemical reaction. The upconversion quantum yield of o-CeO<sub>2</sub> in this nanostructure can be nearly doubled. Furthermore, under NIR light irradiation, the o-CeO<sub>2</sub>@SiO<sub>2</sub>@c-CeO<sub>2</sub> supersandwich structure based composite catalyst displays superior catalytic activity in selective reduction of aromatic nitro compounds to corresponding azo compounds, and the composite photocatalyst can be easily recycled for several times without significant loss of catalytic activity. This strategy may serve as a universal method for the construction of multifunctional nanostructures and shed light on the green chemistry for chemical synthesis.