An XPS Investigation of Mo₂C Catalysts

The highly dispersed Mo₂C catalysts supported on charcoal were prepared by temperature-programmed carburization of precursor MoO₂/C in CH 4/H₂ mixtures.The effects of carburization temperature,Mo-loading,passivation and H₂-reduction on the surface properties were studied by XRD,XPS,CO uptake and specific surface area measurements.The Mo₂C/C catalysts prepared at 680℃ had a high activity in methanation.After H₂-reduction of these passivated catalysts at 600℃,an O/Mo atomic ratios of 0.4～0.5 and a preferential component of Mo⁴⁺ were observed on surface.Only a single peak of C1s was detected at 284.5eV.The nature of active sites is discussed.