Pd-FexOy Hybrid Nanoparticles Encaged Hollow Mesoporous Silica Nanoreactors for Reduction of Nitroarenes to Aminoarenes

In this work, Pd-FexOy hybrid nanoparticles encaged hollow mesoporous silica nanoreactors (Pd-FexOy@HMSNs) are synthesized, which features similar to 3-4 nm Pd-FexOy hybrid nanoparticles inside similar to 17 nm hollow cavities of similar to 32 nm mesoporous silica nanoreactors. By employing Pd and Fe ions containing polymer micelles as templates for silica deposition, hollow mesoporous silica nanoreactors and the residence of functional nanoparticles inside hollow cavities are simultaneously obtained. Through adjusting the ratios of Pd2+/Fe3+ in micelles, various Pd-FexOy@HMSNs with different Pd/Fe ratios are synthesized and tested for reduction of nitroarenes with NaBH4. Relative to Pd@HMSNs, FexOy@HMSNs and their physical mixtures, Pd-1-(FexOy)(1/x)@HMSNs illustrate a greatly enhanced catalytic performance for reductions of a series of substituted nitroarenes with NaBH4 to aminoarenes. The catalytic enhancement of Pd-FexOy@HMSNs is ascribed to the synergistic effect of Pd and FexOy as well as the confinement effect of functional nanoparticles inside hollow cavities.