Molybdenum based catalysts .1. MoO2 as the active species in the reforming of hydrocarbons

The XPS spectra of bulk MoO2 and MoO3 are reported. Commercial MoO2 reveals the presence of multilayers of MoO3 covering bulk MoO2. Zn situ reduction of bulk MoO3 by H-2 at temperatures equal to 623 K and less than 673 K reduces the superficial layer(s) to mainly MoO2. Such phase is characterised by a certain density of states in terms of the free 4d, 5s electrons localised mainly on the Mo atoms and observed in the valence band energy region at the Fermi-level in the XP spectrum of this system. Catalytic reactions on the MoO2 phase of 2-methylpentane at atmospheric pressure using a mixture of the hydrocarbon (5 Torr) with hydrogen (755 Torr) yield 3-methylpentane and n-hexane as the main products in roughly equal amounts. These results are interpreted in terms of dual sites on the MoO2 surface.