Total oxidation of naphthalene using bulk manganese oxide catalysts

Several Mn2O3 catalysts have been synthesized using different preparation methods and tested for the total oxidation of naphthalene, a model polycyclic aromatic compound. The catalysts have been characterized by several physico-chemical techniques such as XRD, TPR, XPS, EDX and TEM. The surface area of the catalyst seems to be of paramount importance, since the mass normalized activity of catalysts increases as the surface area of the Mn2O3 catalysts increases. Consequently, a high surface area ordered mesoporous Mn2O3 catalyst, obtained through a nanocasting route using mesoporous KIT-6 silica as a hard template, was the most efficient catalyst for the deep oxidation of naphthalene. In addition, this catalyst also exerts the highest surface area normalized catalytic activity, which can be related to the highest reducibility and mobility of its lattice oxygen. It was also observed that the Mn2O3 crystalline phase presents a higher intrinsic activity than MnO2.

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► Manganese oxide prepared by nanocasting is highly active for Naphthalene oxidation.
► The reducibility in Mn2O3 catalysts increases when the surface area increases.
► Catalytic activity is linked to the reducibility and mobility of lattice oxygen.
► Mn2O3 presents a higher intrinsic activity for naphthalene oxidation than MnO2.