RARE-EARTHS AS CATALYSTS FOR THE OXIDATIVE COUPLING OF METHANE TO ETHYLENE

Methane activation is a problem of current industrial interest; one of the more studied routes to the direct activation is the oxidative coupling to produce ethylene. Metal oxides are the more used catalyst for the the reaction, and rare earths oxides play an important role due to their characteristics, mainly their thermal stability, low surface area and surface basicity. The surface basicity plays an important role in the reaction mechanism, activating and breaking the methane C-H bonds, and creating the CH3 radicals responsible for the coupling reaction. Further modification of the catalyst surface by alkali metals leads to increased selectivity to hydrocarbons.