Mechanism of first hydrogen abstraction from light alkanes on oxide catalysts

摘要

The activation mechanism of light alkanes is discussed in view of the catalytic properties,and both,bulk and surface properties of active phases.Among the most efficient catalytic systems,four are examined:VPO,Ti(Zr)PO,VSbO and MoVTeNbO.Different activation processes are proposed depending upon the catalyst used but all have the same H abstracting sites corresponding to O~-.The formation of these relatively strong bound species may be related to structure defects(cationic vacancies,excess oxygen)or they might be created through thermally activated electron transfer.Particular emphasis is given to electrical conductivity measurements to evidence the presence of these active oxygen species.