La_2NiO_4复合氧化物的合成及性能研究

SYNTHESIS AND PROPERTIES OF La 2NiO 4

采用Ｐｅｃｈｉｎｉ方法合成了Ｌａ２ＮｉＯ４＋δ粉体，通过ＸＲＤ，Ｏ２ＴＰＤ，ＴＧ和ＸＰＳ等对其物相、氧非计量以及表面状态进行了表征；制备了Ｌａ２ＮｉＯ４＋δ致密透氧膜并考察了其透氧性能．发现其非计量氧的脱出、补充有可逆性；表面吸附氧可转化成Ｏδ－物种，在膜操作状态下，通过体相填隙氧浓差扩散到低氧压侧，以Ｏ２形式脱出，实现连续透氧．

La 2NiO 4+ δ was synthesized through Pechini process. Its structure, nonstoichiometry oxygen and surface property were characterized by XRD, O 2 TPD, TG and XPS. Dense membrane made of this material was prepared by high temperature sintering and its O 2 permeability was determined by GC method. The results indicate that nonstoichiometry oxygen in the material can be removed and regained under different conditions. In membrane operation, O 2 is adsorbed and transferred to O δ - on La 2NiO 4+ δ surface faced with high O 2 pressure side, interstitial oxygen ions diffuse in the bulk, then transferred to O 2 and desorbed at low pressure side. The main charge carriers are interstitial oxygen ion and electronic hole. Interstitial oxygen ion is easier to move as compared with oxygen vacancy in ABO 3- δ material.