Surface structure and catalytic performance of niobium oxides supported on titania

The surface structure and activity of catalytic systems based on niobium oxide supported on titania were investigated. A series of catalysts with Nb content up to 3.6 atoms/nm2 was prepared by incipient wetness impregnation of the titania support with niobium oxalate solutions. Characterization of the system by X-ray diffraction (XRD) and Raman spectroscopy studies did not show evidence of niobium oxide formation. Surface analysis was performed by X-ray photoelectron spectroscopy (XPS), ion scattering spectroscopy (ISS), Raman and infrared spectroscopy. These results were correlated with Brønsted acidity and catalytic activity determined in our previous study. A direct correlation between the catalytic activity and the abundance of Brønsted acid sites had been observed. Analysis of the surface structure by infrared spectroscopy showed a similar evolution for the intensity of the band attributed to polymerized NbOx.

The surface structure and activity of catalytic systems based on niobium oxide supported on titania were characterized by XRD, XPS, Ion Scattering spectroscopy (ISS), Raman and infrared spectroscopy. The catalytic activity for propanol dehydration and the abundance of Brønsted acid sites were directly correlated and their development is consistent with that of the intensity of the infrared band attributed to polymerized NbOx. Figure optionsDownload as PowerPoint slide