Formaldehyde formation in coupled oxidation of methane and methanol over V2O5 and MoO3 silica supported catalysts

The effect of methanol on partial oxidation of methane has been studied on standard molybdena and vanadia catalysts supported on silica. Prior to catalytic tests the catalysts were characterized by BET, SEM/EDAX and TPR/Omethods. Three types of catalytic tests were performed giving temperature and contact time dependence on the catalyst activity and selectivity: partial oxidations of methane, methanol and methane/methanol mixtures. The methanol showed an activating impact on the partial oxidation of methane over all used catalysts samples, but the strongest one over MoO 3 /SiO 2 . In the absence of CH 3 OH the only catalyst, which exhibited HCHO selectivity, was a low loaded vanadia catalyst. It has been put forward that methanol may enhance formation of oxygen active species, prerequisites for activating methane molecules, through reducing vanadia cations and causing breakage of vanadium oxygen bonds.