PARTIAL OXIDATION OF METHANE TO FORMALDEHYDE BY LITHIUM PROMOTED VPO CATALYSTS

The effect of the addition of lithium cations to VPO phases on the cat alytic activity of methane selective oxidation is reported. Two differ ent methods of Li+ addition were used: redox intercalation and co-prec ipitation. The redox intercalation procedure led to the most active pr omoted catalyst. XRD, FTIR, XPS characterization, oxygen isotopic exch ange experiments and catalytic activity measurements using double-bed configuration were carried out. It is proposed that VPO activates meth ane forming of the intermediates which are further selectively oxidize d by the Li+ species and that the intercalation method allows the Lito be well dispersed in the VPO surface and not covering completely th e surface of the catalyst.