Characterization of metal-incorporated molecular sieves

Abstract Metal-containing aluminophosphate molecular sieves (MeAPOs) were observed to exhibit remarkable catalytic activity in partial oxidation of hydrocarbons under mild condition. In this paper we review the spectroscopic characterization of framework incorporation and redox behavior of vanadium and cobalt in MeAPOs. EXAFS/XANES and XPS studies of the oxidation state and coordination of V and Co in as-prepared MeAPOs and after redox treatments will also be presented. These studies show that fourfold coordinated Co 2+ of CoAPO-11 was only partially oxidized to Co 3+ , while grafted V 4+ of VAPO-5 was almost completely oxidized to V 5+ after calcination. All Co and V species remain in the AlPO 4 framework during redox treatments.