Structure Engineering of Yolk–Shell Magnetic Mesoporous Silica Microspheres with Broccoli‐Like Morphology for Efficient Catalysis and Enhanced Cellular Uptake

Abstract Yolk–shell magnetic mesoporous microspheres exhibit potential applications in biomedicine, bioseparation, and catalysis. Most previous reports focus on establishing various interface assembly strategies to construct yolk–shell mesoporous structures, while little work has been done to control their surface topology and study their relevant applications. Herein, a unique kind of broccoli‐like yolk–shell magnetic mesoporous silica (YS‐BMM) microsphere is fabricated through a surfactant‐free kinetic controlled interface assembly strategy. The obtained YS‐BMM microspheres possess a well‐defined structure consisting of a magnetic core, middle void, mesoporous silica shell with tunable surface roughness, large superparamagnetism (36.4 emu g −1 ), high specific surface area (174 m 2 g −1 ), and large mesopores of 10.9 nm. Thanks to these merits and properties, the YS‐BMM microspheres are demonstrated to be an ideal support for immobilization of ultrafine Pt nanoparticles (≈3.7 nm) and serve as superior nanocatalysts for hydrogenation of 4‐nitrophenol with yield of over 90% and good magnetic recyclability. Furthermore, YS‐BMM microspheres show excellent biocompatibility and can be easily phagocytosed by osteoclasts, revealing a potential candidate in sustained drug release in orthopedic disease therapy.