The effect of oxygen vacancy of alkaline-earth metal Sr doped Sm2Zr2O7 catalysts in the oxidative coupling of methane

摘要

A series of the Sr/Sm2Zr2O7 catalysts with different Sr contents prepared by the coprecipitation method were used for OCM. The results revealed that the basicity and oxygen vacancies concentration on the surface of the Sm2Zr2O7 catalyst were notably increased because of the addition of Sr. Activation of O-2 by the oxygen vacancies was responsible for the formation of C-2. Specifically, the 7.6% Sr/Sm2Zr2O7 catalyst possessed 18.4% C-2 yield at 750 degrees C due to the presence of moderate basicity and the highest ratio of the oxygen species O-2(-) to lattice oxygen O-2(-). More importantly, the 7.6%Sr/Sm2Zr2O7 catalyst possessed high stability.