THE PERFORMANCE AND STRUCTURE OF RARE-EARTH-OXIDES MODIFIED BY STRONTIUM FLUORIDE FOR METHANE OXIDATIVE COUPLING

Strontium fluoride promoted rare earth (La, Nd, Sm, Eu, Gd, Dy, and Y) oxides were more selective than the corresponding unpromoted rare ear th oxides for the methane oxidative coupling to ethane and ethene. The XRD results indicated that the partial anionic or cationic exchanges and interaction between the oxide and fluoride phases took place in mo st of the catalysts studied in this paper, leading to the formation of new oxyfluoride phases. The possible formation of anionic vacancies i n the lattice as the result of ionic exchange and interaction between the phases will be favorable to the activation of molecular oxygen and the improvement of catalytic performance.