Palladium nanoparticles supported on SiO2@Fe3O4@m-MnO2 mesoporous microspheres as a highly efficient and recyclable catalyst for hydrodechlorination of 2,4-dichlorophenol and reduction of nitroaromatic compounds and organic dyes

In this study, magnetic SiO 2 @Fe 3 O 4 @m-MnO 2 microspheres with uniform morphology and mesoporous MnO 2 shell were successfully prepared. The MnO 2 sheets structured mesoporous shell could provide a large specific surface area, thereby increasing the catalytically active sites. Thus, magnetic SiO 2 @Fe 3 O 4 @m-MnO 2 microspheres were used as a catalyst support. Palladium nanoparticles (Pd NPs) were successfully anchored with high dispersion on SiO 2 @Fe 3 O 4 @m-MnO 2 surface, successfully obtained Pd(6%)/SiO 2 @Fe 3 O 4 @m-MnO 2 nanocatalyst with a Pd weight percentage of 6%. The obtained nanocatalyst was employed in the hydrodechlorination of highly toxic 2,4-dichlorophenol and catalytic reduction of the widely used nitroaromatics and organic dyes under ambient conditions. In these catalytic reactions, the Pd(6%)/SiO 2 @Fe 3 O 4 @m-MnO 2 nanocatalyst with large and accessible pore surface area exhibited excellent catalytic activity as compared to other noble metal supported catalysts. The Pd(6%)/SiO 2 @Fe 3 O 4 @m-MnO 2 nanocatalyst could also be easily and conveniently recovered from the reaction mixture by using an external magnet, attributed to its magnetism, thus preventing the catalyst loss. Moreover, it could also be reused for at least six times without significant decrease in the catalytic activity, indicating its excellent reusability and stability. This study provides a useful platform and a new perspective for fabricating mesoporous MnO 2 microspheres based noble metals modified catalysts for environmental catalysis.