Metalloporphyrin-based nanocatalysts for aerobic oxidation: A comparative evaluation

This research presents a comparative study of iron-, manganese-, and copper-based porphyrins covalently immobilized on the surfaces of multi-walled carbon nanotubes (MWCNTs) and graphene oxide (GO) as heterogeneous nanocatalysts for the oxidation of olefins with molecular oxygen under catalyst-free conditions. All catalysts were synthesized and their structures characterized using UV-Vis, FT-IR, atomic absorption spectroscopy, X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Their catalytic performance was then evaluated in olefin oxidation reactions using molecular oxygen as the green oxidant. The results show that MWCNT-supported catalysts, especially Fe(TCPP)Cl@MWCNT and CuTCPP@MWCNT, demonstrate superior catalytic activity and turnover numbers compared to their GO-supported counterparts, with Fe(TCPP)Cl@MWCNT achieving the highest efficiency. The separation and recovery of the nanocatalyst were simple, effective, and economical in this green oxidation process. Overall, these findings highlight the promise of metalloporphyrin-functionalized carbon nanomaterials as efficient, reusable, and environmentally friendly catalysts for aerobic oxidation, emphasizing the critical roles of both the central metal ion and the support material in catalytic performance.