Manganese and cobalt-terephthalate metal-organic frameworks as a precursor for synthesis of Mn2O3, Mn3O4 and Co3O4 nanoparticles: Active catalysts for olefin heterogeneous oxidation

• Co3O4, Mn3O4 and Mn2O3 nanoparticles (NPs) were prepared by hydrothermal decomposition of Mn and Co-terephthalate MOFs.
• These NPs exhibit excellent catalytic activity and stability in olefins oxidation.
• High activity and selectivity, easy separation and appropriate performance in the recycling reaction, make these NPs valuable.

The thermal decomposition of manganese and cobalt-terephthalate Metal-Organic Framework precursors was utilized as a synthetic route for fabrication of Co3O4, Mn3O4 and Mn2O3 nanoparticles. The prepared metal oxide nanoparticles of Co3O4, Mn3O4 and Mn2O3 possess average size diameter of 40, 60 and 80 nm respectively. The findings demonstrate that spinel structure nanoparticles of Co3O4 and Mn3O4 exhibit efficient catalytic activity toward heterogeneous olefin epoxidation in the presence of tert-butyl hydroperoxide. In addition, Co3O4 and Mn3O4 nanoparticles illustrated excellent catalytic stability and reusability for nine and four cycles, respectively, toward olefin oxidation.

Spinel structured Mn3O4 and Co3O4 and Mn2O3 nanoparticles were prepared by thermal decomposition of manganese and cobalt-terephthalate Metal-Organic Framework (MOF) precursor at 400, 500 and 600 °C. Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared and X-ray diffraction spectrometry were used to characterize the phase and the morphology of the metal oxide nanoparticles. Characterization of prepared nanoparticles was indicated that these nanoparticles have average size diameter 60, 40 and 80 nm for Mn3O4, Co3O4 and Mn2O3 respectively. Catalytic efficacy of Mn3O4 and Co3O4 nanoparticles was evaluated in the epoxidation of a variety of alkenes using tert-butyl hydroperoxide as an oxidant. In addition, metal oxide nanoparticles exhibited excellent catalytic stability in several runs, demonstrating that these heterogeneous and recyclable catalysts are promising for olefin epoxidation.Figure optionsDownload as PowerPoint slide