Synthesis and characterization of niobium oxide layers on silica and the interaction with nickel

A surface phase oxide containing niobiuma oxide, deposited on non-porous si lica was prepared by two different methods. The photoelectron spectroscopy (XPS) and infrared results show that the method using five-stage attaching reactions between Nb(OC2O5)(5) and silanol led to a very close one-atomic-l ayer niobium oxide structure on SiO2. This sample presented two oxygen spec ies comparable to model systems and it was possible to distinguish them in the XPS spectral even when using a silica powder. Cyclohexane dehydrogenati on was used to characterize the reduced metallic surface. The nickel compou nds interact preferentially with niobia rather than with silica. These nick el species favored lower dehydrogenation activity, suggesting the choice of niobia as a nickel trap. (C) 2000 Elsevier Science B.V. All rights reserve d.