Metal–Organic Framework-Derived Mn₃O₄/Co₃O₄/C/SiO₂ Nanostructures for Catalytic Oxidation Reactions

In this work, metal–organic framework-derived Mn3O4/Co3O4/C/SiO2 (MCCO) nanostructures were developed. Primarily, Mn3O4 nanoparticles prepared via pristine synthetic approach at room temperature were integrated with ZIF-67/SiO2 (ZFS) to attain Mn3O4/ZIF-67/SiO2 (ZFSM). ZFSM was carbonized at 600 °C in an argon atmosphere followed by thermal treatment at 250 °C in air to acquire the final MCCO catalyst. The MCCO was used for the catalytic oxidation of C–H bonds, cycloalkanes, and alcohols under air atmosphere and neat reaction conditions. The other notable aspects of MCCO-catalyzed oxidation reaction include low catalyst loading (2 mg), high yield of oxygenated products, and wide substrate applicability. The exceptional catalytic behavior of MCCO can be attributed to the complementarity among Mn3O4–Co3O4 and synergistic contributions from different components of MCCO such as (a) the confinement effect of SiO2 coating which stabilizes the catalytic sites via encapsulation and (b) the presence of graphitized carbon component which enhances the electron transport, leading to faster reaction kinetics. The MCCO catalyst can be effortlessly recovered via an external magnetic force and exhibits exceptional reusability up to ten catalytic cycles while preserving high catalytic performance and structural aspects. Moreover, the practical utility of the current protocol was depicted by MCCO catalyzed gram-scale synthesis of high-value chemicals like acetophenone and vanillin. Overall, these outcomes represent a viable approach toward the development of hybrid catalytic systems for achieving high-value chemicals via a green and sustainable route.