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.