Enabling synchronous activation of inner-core and mesoporous outer-shell of monodispersed Fe₃O₄@SiO₂ by in-situ implanted MnO_x to synergistically deliver enhanced catalytic activity

Herein, we report a facile synthetic method enabling the synchronously activated decoration of the inner core and mesoporous outer shell of monodispersed Fe₃O₄@meso-silica using in situ implanted MnO_x. This approach can maintain the catalytic activity of the internal core without loss of its inherent magnetic properties even when undergoing calcination. The developed catalyst exhibits a well-defined core-shell configuration with a MnO_x coating on an Fe₃O₄ internal core and a MnO_x-modified mesoporous outer shell, obtained via only a one-pot output cycle. The thin MnO_x coating layer prevents excess oxidation of the unoxidized Fe₃O₄ core during the annealing process. Additionally, the mesopores in the coated silica were synchronously functionalized by the assistance of dodecylamine (DDA) as surfactant because of the coordination effect of Mn²⁺ and DDA molecules. The optimal nanocatalyst exhibits improved catalytic activity for styrene oxidation and recoverability due to its magnetic-responsive properties, in contrast to postsynthesized and shell-only functionalized catalysts.