甲烷氧化偶联含锂多元复合氧化物催化剂的失活机理

对甲烷氧化偶联反应活性较高的多元复合氧化物催化剂（Ｌｉ－Ｔｉ－Ｌａ，Ｌｉ－Ｍｎ－Ｌａ，Ｌｉ－Ｎｉ－Ｌａ）的稳定性和失活机理进行了初步探讨，利用ＸＲＤ，ＩＲ，ＸＰＳ和Ｏ２－ＴＰＤ等方面对催化剂进行了表征，结果表明，催化剂在高温及反应气氛的作用下，表面锂的流失，使体相晶格中的锂向表面扩散，导致含锂活性相结构的分解（或部分分解），从而减少了体相相氧空位和生氧种的数量，降低了晶格氧的活动性，致使催化剂活必

STUDIES ON DEACTIVATION OF Li-DOPED MULTICOMPONENT COMPLEX OXIDE CATALYSTS FOR OXIDATIVE COUPLING OF METHANE

he deactivation of highly active multicomponent oxide catalysts Li-M-La (M =Ti, Mn, Ni) at high reaction temperature has been studied. The surface structure and bulk structure of the catalysts were characterized by means of XRD, IR, XPS, BET, O2-TPD etc. The results show that the deactivation of the catalyst at high temperature and reaction atmosphere is mainly due to the loss of surface lithium. As a result, the diffusion of lithium from bulk to surface leads to decomposition of the active phase containing lithium, which lowers the number of oxygen vacancies and active oxygen species and decreases the mobility of lattice oxygen.