Structural change of molybdenum on silica–alumina in contact with propene studied by ESR and Mo LIII-edge XANES

Structure and reducibility of titania-supported monomeric and dimeric molybdenum oxide entities studied by DFT calculations

“…They concluded that at least two molybdenum centres are required to perform methanol oxidation (a two electrons oxidation) and confirmed that isolated species are inactive as they cannot be reduced to Mo 5+ . These conclusions are supported by the study of Aritani et al [17] that showed polymeric molybdenum oxide species contacted with propene yield a large amount of Mo 5+ . They could identify two kinds of paramagnetic centres, namely one pentacoordinated and one hexacoordinated molybdenum differing by their EPR signature.…”

Spectroscopic characterization of Cl-modified Mo/Si:Ti catalysts for oxidative dehydrogenation of propane

“…One can see that after propane reduction, the coordination of Mo(V) species changes from a hexa-coordination to a penta-coordination environment due to the loss of oxygen. This hexa to penta coordination change has been observed on silica-alumina supported molybdenum catalysts after a similar reduction treatment using propylene followed by evacuation [57]. Double integration of the spectra in figure 3 gives the intensity from Mo(V) species.…”

Molecular-scale mechanisms of distribution and isotopic fractionation of molybdenum between seawater and ferromanganese oxides

“…In the catalysis science, structures of surface Mo species have been extensively investigated for various oxides such as MgO, Al 2 O 3 , SiO 2 , and TiO 2 over the past decades (e.g., Mensch et al, 1988;Bare et al, 1993;Aritani et al, 1996Aritani et al, , 2001Takenaka et al, 1998;Radhakrishnan et al, 2001;Lede et al, 2002). Parts of the previous reports are summarized with our present findings in Table 4 (Kim et al, 1992;Shimada et al, 1992;Hu et al, 1995).…”

“…The structural analyses of Mo on the surface of various oxides, such as MgO, Al 2 O 3 , SiO 2 , and TiO 2 , have vigorously been conducted by XAFS analysis in the field of catalysis science (e.g., Mensch et al, 1988;Bare et al, 1993;Aritani et al, 1996Aritani et al, , 2001Takenaka et al, 1998;Radhakrishnan et al, 2001;Lede et al, 2002). This method is also a powerful tool in the geochemistry field because it enables in situ analysis of the surface complex structure of trace elements at the solid/water interface.…”