锶掺杂的La_(2)Ce_(2)O_(7)烧绿石催化甲烷氧化偶联性能研究  

Research on Sr doped La_(2)Ce_(2)O_(7) pyrochlore as catalyst for oxidative coupling of methane

作　　者：武国号 Palle Ramana Murthy 陈冰冰 张晓 石川[1] 宋春山[1,2] 郭新闻 WU Guo-hao;PALLE Ramana-Murthy;CHEN Bing-bing;ZHANG Xiao;SHI Chuan;SONG Chun-shan;GUO Xin-wen(State Key Laboratory of Fine Chemicals,School of Chemical Engineering,Dalian University of Technology,Dalian 116024,China;Department of Chemistry,Faculty of Science,The Chinese University of Hong Kong,Shatin,NT 999077,China)

机构地区：[1]大连理工大学化工学院精细化工国家重点实验室,辽宁大连116024 [2]香港中文大学理学院化学系,中国香港999077

出　　处：《现代化工》2022年第4期109-115,122,共8页Modern Chemical Industry

基　　金：国家自然科学基金(21872014,21932002);国家重点研发计划(2017YFA0700103);中央高校基本科研业务费(DUT20ZD205)。

摘　　要：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La_(2)Ce_(2)O_(7)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La_(2)Ce_(2)O_(7)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_(1.5)Sr_(0.5)Ce_(2)O_(7)催化剂上,800℃下可以获得57%的C_(2)选择性和14%以上的C_(2)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,La_(2)Ce_(2)O_(7) are synthesized through the sol-gel method.La_(2)Ce_(2)O_(7) 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,H_(2)-TPR,XPS and CO_(2)-TPD.XRD pattern shows the defective fluorite phase of La_(2)Ce_(2)O_(7) sample.The quantitative analysis via H_(2)-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 C_(2) and the yield 14%for C_(2) can be obtained at 800℃over the optimized La_(1.5)Sr_(0.5)Ce_(2)O_(7) sample,which remains stable performance during 30 h of consecutive running.

关 键 词：La_(2)Ce_(2)O_(7) 锶掺杂 晶格氧物种 甲烷 氧化偶联 

分 类 号：O643[理学—物理化学]