Active species and working mechanism of silica supported MoO3 and V2O5 catalysts in the selective oxidation of light alkanes

Abstract

Publisher Summary Supported MoO3 and V2O5 based catalysts play an excellent role in the selective oxidation of light (C1–C3) alkanes. Because of this, a considerable research effort has been directed to ascertain the working mechanism of such oxide systems as well as the nature of the active sites and the origin of the oxygen involved in the formation of the reaction products. This chapter discusses the catalytic behavior of silica supported MoO3 and V2O5 systems in both the selective oxidation of methane to formaldehyde (MPO) and the oxidative dehydrogenation of propane to propylene (POD), disclosing that V2O5 acts as a promoter of the reactivity of the SiO2 surface while the action of MoO3 strictly depends on the kind of the silica support. This chapter explains the correlation between the catalytic patterns of differently loaded silica supported MoO3 and V2O5 catalysts in myeloperoxidase (MPO) and peroxi-dase (POD) reactions with their surface and redox features to highlight the nature of the active surface species in the selective oxidation of light alkanes. The study clearly indicates a direct relationship between the density of reduced sites of low-medium loaded silica based oxide catalysts and reaction rate in both MPO and POD strongly suggests the occurrence of a concerted reaction mechanism, involving the activation of gas-phase O2, on the reduced sites of the catalyst surface.