Controlled Synthesis of Manganese Oxide Nanoparticles Encaged in Hollow Mesoporous Silica Nanoreactors and Their Enhanced Dye Degradation Activity.

In this study, controlled synthesis of hollow mesoporous silica nanoreactors with small manganese oxide nanoparticles in their cavities (Mn O @HMSNs) is reported, and the dye degradation performance in the presence of hydrogen peroxide over Mn O @HMSNs is investigated. Specifically, triple ligands (a compound with three dipicolinic acid groups) were used to coordinate manganese ions to form negatively charged coordination complex networks, which further combine with positively charged copolymers to obtain metal ion-containing polymer micelles. Following silica deposition onto micellar coronas and calcinations simultaneously result in hollow mesoporous silica nanoreactors and manganese oxide nanoparticles in their cavities. In this work, the influences of synthetic parameters on the structures are studied in detail. The obtained Mn O @HMSNs show greatly enhanced activity and stability for a series of dye degradations. The performance enhancement is ascribed to their unique nanostructures, where mesoporous silica walls provide protection to the inner Mn O nanoparticles and the small size of the manganese oxide nanoparticles greatly enhances the dye degradation activity.