02306nas a2200277 4500008004100000022001400041245013200055210006900187260000800256300001400264490000800278520130000286653002601586653002301612653003001635653002101665653003901686653002701725100002401752700002201776700002801798700002601826700002501852700002401877856012701901 2020 eng d a1011-372X00aHighly dispersed MnOx nanoparticles on shape-controlled SiO2 spheres for ecofriendly selective allylic oxidation of cyclohexene0 aHighly dispersed MnOx nanoparticles on shapecontrolled SiO2 sphe cOCT a3023-30350 v1503 a

Shape-controlled metal nanomaterials are considered as a unique class of catalysts because of their synergistic size- and shape-dependent catalytic properties. This work reports the synthesis of a novel size- and shape-controlled catalyst, consisting of highly dispersed MnOx nanoparticles (average particle size of 4.5 nm) on shape-controlled SiO2 nanospheres (250-300 nm) for selective cyclohexene oxidation using air as the oxidant under solvent- and base-free conditions. The MnOx/SiO2 catalyst exhibited an excellent cyclohexene conversion (92%) with a high selectivity (96%) to the allylic products (2-cyclohexene-ol and 2-cyclohexene-one) under mild conditions, outperforming various SiO2 supported CoOx, FeOx, and CuOx catalysts. The better performance of shape-controlled MnOx/SiO2 nanocatalyst is due to high redox nature of Mn, uniform dispersion of smaller sized MnOx nanoparticles, and synergetic interaction between MnOx and SiO2 spheres, as evidenced by XPS and TEM studies. Further, the MnOx/SiO2 catalyst could be reused at least 5 times for selective cyclohexene oxidation with a negligible loss in its catalytic performance, indicating the excellent stability of shape-controlled metal nanocatalysts in organic synthesis under economically viable and mild conditions.

10aCyclohexene oxidation10aMnOx nanoparticles10aShape-controlled catalyst10aSiO2 nanospheres10aStructure-performance relationship10aSynergetic interaction1 aRao, Bolla, Govinda1 aSudarsanam, Putla1 aRao, Tumula, Venkateshw1 aAmin, Mohamad, Hassan1 aBhargava, Suresh, K.1 aReddy, Benjaram, M. uhttps://library.ncl.res.in/content/highly-dispersed-mnox-nanoparticles-shape-controlled-sio2-spheres-ecofriendly-selective