新型催化材料Sr_2FeMoO_6的葡萄糖溶胶-凝胶法合成及甲烷催化燃烧性能

Preparation of novel catalyst Sr_2FeMoO_6 and its catalytic performance in methane combustion

采用葡萄糖溶胶-凝胶法合成了Sr2FeMoO6催化剂,研究了空气、氩气和H2/N23种焙烧气氛对产物的结构和性能的影响。运用X射线衍射(XRD)、程序升温还原(TPR)、傅里叶变换红外光谱(FT-IR)、比表面(BET)及磁性测量与甲烷催化燃烧活性评价等技术对所制备的样品进行了表征。XRD实验结果表明,H2/N2气氛下焙烧得到的样品是单相的双层钙钛矿结构氧化物Sr2FeMoO6,在氩气下焙烧的样品形成了主相为双层钙钛矿结构氧化物Sr2FeMoO6,同时伴有少量的SrMoO4相,但在空气下焙烧的样品中除了Sr2FeMoO6的衍射峰,还出现了强度很高的SrMoO4相的衍射峰。从TPR、FT-IR和磁性表征结果发现,不同的焙烧气氛所形成的样品程序升温还原图谱和红外光谱均有所差别,H2/N2气氛下合成的样品有较好的磁性,而氩气和空气下合成的样品的磁性几乎为零。对于H2/N2气氛下合成的单相Sr2FeMoO6样品的甲烷催化燃烧活性测试表明,甲烷燃烧起燃温度T10为475℃,完全转换温度T100为744℃,可见单相双层钙钛矿型结构化合物Sr2FeMoO6对甲烷催化燃烧也有很好的活性。

The double perovskite catalyst Sr2FeMoO6 was prepared by the sol-gel method using glucose as complex agent, at 1100℃ for 3 h.The structure and performance of the catalyst prepared in various calcination atmospheres （H2/N2 mixed gas, argon, and air atmospheres） were investigated.The catalyst was characterized by means of X-ray diffraction （XRD）, temperature programmed reduction （TPR）, Fourier transform infrared spectroscopy （FT-IR）,specific surface area and magnetism techniques.Meanwhile the catalytic activity of double perovskite Sr2FeMoO6 in methane catalytic combustion was investigated.The XRD results indicated that single-phase double Sr2FeMoO6 was found in the catalyst, calcined in H2/N2 mixed gas.Double perovskite was the dominant phase, accompanied by a few scheelite-type SrMoO4 in the catalyst calcined in argon atmosphere,whereas besides double perovskite phase a stronger SrMoO4 phase was found in the catalyst calcined in air atmosphere.FT-IR and TPR results indicated that TPR spectrum and infrared spectroscopy of catalyst calcined in different atmospheres were different.The catalyst calcined in H2/N2 mixed gas had better magnetic property, whereas the catalyst calcined in argon and air atmospheres had little magnetism.The T10（temperature for 10% methane conversion） and T100（temperature for 100% methane conversion） of single-phase Sr2FeMoO6 double peroskite were 475℃and 744℃ respectively.So single-phase double perovskite Sr2FeMoO6 had good catalytic activity for methane catalytic combustion.