非水溶剂溶胶-凝胶法制备的纳米卤氧化镧在甲烷氧化偶联反应中的应用  

Nano-lanthanum Oxyhalide Prepared by Nonaqueous Sol-Gel for Oxidative Coupling of Methane

作　　者：侯玉慧[1] 常刚[1] 翁维正[1] 夏文生[1] 万惠霖[1] 

机构地区：[1]厦门大学化学化工学院,固体表面物理化学国家重点实验室,醇醚酯清洁化工国家工程实验室,福建厦门361005

出　　处：《催化学报》2011年第9期1531-1536,共6页

基　　金：国家重点基础研究发展计划(973计划,2010CB732303);国家自然科学基金(21033006,20923004,20373054)~~

摘　　要：采用非水溶剂溶胶-凝胶法制备了具有四方晶体相结构的纳米LaOX(X=Cl,Br).X射线粉末衍射和扫描电子显微镜结果表明,纳米LaOX样品的形貌规整、粒径均匀(平均粒径约为47nm).在甲烷氧化偶联(OCM)反应中,纳米LaOX显示出比常规尺度LaOX更高的催化活性和C2选择性,且纳米LaOX具有良好的稳定性.此外,常规尺度下,LaOBr催化剂活性和C2选择性高于LaOCl;纳米尺度下,两催化剂活性相差不大,但LaOBr上C2选择性明显更高.LaOX （X = Cl, Br） nanoparticles with tetragonal crystal structure were successfully prepared via sol-gel approach with non-aqueous solvents. Characterizations by X-ray powder diffraction and scanning electronic microscopy show that the LaOX nanoparticles are regularly in shape and highly uniform in size with an average diameter of about 47 nm. For oxidative coupling of methane （OCM）, the nanosize LaOX catalysts have higher methane conversion and C2 selectivity than the LaOX catalysts with conventional size and show good stability in activity and selectivity during the catalyst life test at 650 °C. At conventional size, the methane conversion and C2 selectivity for OCM over the LaOBr catalyst are higher than that over the LaOCl catalyst, and at nanosize, there is not so much difference in methane conversion between LaOBr and LaOCl. However, the C2 selectivity for OCM reaction over LaOBr is significantly higher than that over LaOCl, especially at low temperature.

关 键 词：纳米 卤氧化镧 甲烷氧化偶联 溶胶-凝胶 非水溶剂 低温活化 

分 类 号：O643.32[理学—物理化学]