objective to develop catalysts having application potential for oxidative coupling of methane (OCM) at relatively lower temperature. A series of Ln2Zr2O7 compounds with varied rare earth A sites have been prepared by a co-precipitation method. XRD and Raman have proved that pure Ln2Zr2O7 compounds have been successfully prepared for all the catalysts. By decreasing the rA/rB ratio, their crystalline structure
摘要目的开发具有在较低温度下
甲烷氧化偶联(OCM)的应用潜力的催化剂。通过共沉淀法制备了一系列具有不同稀土A位点的Ln2Zr2O7化合物。XRD和Raman证明,已经成功地为所有催化剂制备了纯Ln2Zr2O7化合物。通过降低rA / rB比,它们的晶体结构从有序的烧绿石(La2Zr2O7)转变为不太有序的烧绿石(Pr2Zr2O7和Sm2Zr2O7),最终转变为有缺陷的立方
萤石相(Y2Zr2O7)。H2-TPR,O2-
TPD和XPS已证明表面活性O2-的数量遵循La2Zr2O7> Pr2Zr2O7> Sm2Zr2O7> Y2Zr2O7的顺序,这与反应性能非常吻合,表明表面O2-的丰度是影响反应性能的关键因素。
CO2-
TPD已证明,较好的催化剂通常具有大量的表面中等碱位,这是影响反应性能的另一个因素。结论是,两种类型的表面活性中心之间的协调相互作用控制了Ln2Zr2O7催化剂的反应性能。与最先进的Mn