Cetyl alcohol mediated fabrication of forest of Ag/Mn3O4 nanowhiskers catalyst for the selective oxidation of styrene with molecular oxygen

Cetyl alcohol-mediated water-based preparation of nanocrystalline Ag/Mn3O4 catalyst has been reported in a one-pot preparation method. This catalyst has been characterized by XRD, XPS, SEM, TEM, STEM-mapping, FTIR, Raman and ICP-AES. Electron microscopy displayed the formation of whisker-like one-dimensional structure. TEM-images revealed the formation of ultrasmall Ag (with average size 5 nm), anchored on hausmannite-type tetragonal Mn3O4 spinel (with diameter 30-40 nm). It was found that the catalyst can effectively oxidize styrene with molecular O-2 as oxidant. The effect of different reaction parameters like reaction temperature, pressure of oxygen gas, reaction time etc. have been investigated in detail. A styrene conversion of 67% with a styrene-oxide selectivity of 100% accomplished over this catalyst. Nano-whiskers like unique morphology of the catalyst and the thorough dispersion of Ag nanoparticles on Mn3O4 spinel support are the detrimental factors of the reactivity of the catalyst. The catalyst did not show any leaching up to five reuses, showing its true heterogeneity nature.