Construction of a sandwich-like UiO-66-NH2@Pt@mSiO2 catalyst for one-pot cascade reductive amination of nitrobenzene with benzaldehyde

Heterogeneous noble metal-based catalysts with stable, precise structures and high catalytic performance are of great research interest for sustainable catalysis. Herein, we designed the novel sandwich-like metal-organic-framework composite nanocatalyst UiO-66-NH2@Pt@mSiO2 using UiO-66-NH2@Pt as the core, and mesoporous SiO2 as the shell. The obtained UiO-66-NH2@Pt@mSiO2 catalyst shows a well-defined structure and interface, and the protection of the mSiO2 shell can efficiently prevent Pt NPs from aggregating and leaching in the reaction process. In the one-pot cascade reaction of nitroarenes and aromatic aldehydes to secondary amines, UiO-66-NH2@Pt@mSiO2 shows excellent catalytic performance due to acid catalytic sites provided by UiO-66-NH2 and Pt hydrogenation catalytic sites. Furthermore, the porous structure of the UiO-66-NH2@Pt@mSiO2 catalyst also enhances reactant diffusion and improves the reaction efficiency. This work provides a new avenue to meticulously design well-defined nanocatalysts with superior catalytic performance and stability for challenging reactions.