EFFECT OF VANADIUM-OXIDE LOADING ON THE SELECTIVE OXIDATION OF METHANE OVER V2O5 SIO2/

The effect of vanadium oxide loading on the selective methane oxidatio n over V2O5/SiO2 Catalysts was investigated. X-ray diffraction (XRD) a nd temperature-programmed reduction (TPR) were used to characterize th ese catalysts. The results of XRD and TPR show that the catalysts with 1-8 wt % vanadium oxide loadings had an uniform structure but no well -defined crystalline phase of vanadium oxide. These catalysts showed v ery different selectivities for methanol. At the fixed methane convers ion, methanol selectivity generally increased with the decrease of the vanadium oxide loading. The size of vanadium oxide ensembles may have significant effect on catalytic selectivity. N2O was found to be much more active than O2 for the oxidation of methane. In the presence of both N2O and O2, N2O had to compete with O2 for the adsorption sites.