Insights into the nature of alumina-supported MnOOH and its catalytic performance in the aerobic oxidation of benzyl alcohol

We report the synthesis of alumina-supported manganese catalysts by a homogeneous deposition–precipitation method and their catalytic application in the aerobic oxidation of benzyl alcohol. Benzyl alcohol conversion of 93% was achieved with benzaldehyde as the main product. This Mn-based catalyst can be recycled up to six times without losing catalytic activity. X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) indicated that MnOOH species are highly dispersed on the alumina surface at low Mn loadings (<10 wt.%). These MnOOH species aggregated into Mn3O4 crystallites at high Mn loadings.