基于烧绿石类材料热稳定性高、晶格氧流动性可调控的特点,通过溶胶-凝胶法制备了La₂Ce₂O₇催化剂,向其中掺杂碱土金属Sr,研究了其在甲烷氧化偶联(OCM)反应中的催化性能。通过一系列表征确认了La₂Ce₂O₇样品的缺陷立方萤石结构;锶掺杂不仅显著提高了晶格氧的活动性,还提升了催化剂表面强碱位点的比例;与OCM反应活性关联发现,晶格氧流动性增强以及表面强碱位点的增加是提高OCM反应活性的关键因素;在优化的La_1.5Sr_0.5Ce₂O₇催化剂上,800℃下可以获得57%的C₂选择性和14%以上的C₂收率,连续反应30 h性能保持稳定。

Based on the superior thermal stability as well as the controlled lattice oxygen mobility of pyrochlore materials,La₂Ce₂O₇ are synthesized through the sol-gel method.La₂Ce₂O₇ catalyst is further doped with Sr,and its catalytic performance in oxidative coupling of methane (OCM) is evaluated.The catalysts are characterized by powder-XRD,Raman,H₂-TPR,XPS and CO₂-TPD.XRD pattern shows the defective fluorite phase of La₂Ce₂O₇ sample.The quantitative analysis via H₂-TPR reveals that Sr doping increases greatly the activity of lattice oxygen and raises the ratio of strong base site on the surface of catalysts.It is found through correlating the structure properties with OCM activity that the enhancement of mobility of lattice oxygen and the increase of strong base sites on the surface are the key factors to improve the reactivity of OCM.Therefore,the 57% selectivity for C₂ and the yield 14% for C₂ can be obtained at 800℃ over the optimized La_1.5Sr_0.5Ce₂O₇ sample,which remains stable performance during 30 h of consecutive running.

武国号(1997-),男,硕士研究生,研究方向为甲烷转化、多相催化,18340878859@163.com