【作者】 白峰；

【导师】 胡瑞生；

【作者基本信息】 内蒙古大学 ， 物理化学， 2009， 硕士

【摘要】 采用不同制备方法制备了稀土双钙钛矿复合氧化物LaSrFeCoO₆催化剂,使用XRD、FT-IR、H₂-TPR、SEM、XPS和磁性等表征手段对比研究了制备方法对LaSrFeCoO₆催化剂甲烷燃烧活性的影响。实验结果表明,采用溶胶-凝胶法以柠檬酸、葡萄糖、蔗糖为络合剂,在空气气氛下1100℃焙烧3h后形成单一相物相。柠檬酸为络合剂的甲烷燃烧催化活性最好,起然温度和完全转化温度分别为:432.7℃和639.2℃。络合剂对催化剂比表面影响较大且比表面与催化活性成顺变关系。对溶胶-凝胶法以柠檬酸为络合剂的LaSrFeCoO₆催化剂在不同焙烧温度下的化学与物理性能比较。在空气气氛下500℃焙烧3h后形成单一相物相,说明溶胶.凝胶法在较低的焙烧温度下可以合成双钙钛矿复合氧化物。焙烧温度对催化剂比表面影响较大,此外表观活化能也是影响催化活性的重要因素。采用非晶态合金法、溶胶-凝胶法、微乳法制备双钙钛矿复合氧化物LaSrFeCoO₆,在空气气氛下1100℃焙烧3h后,三种制备方法均形成单一双钙钛矿物相。非晶态合金法制备的样品在氢还原能力、表面电子密度、表观活化能等方面都表现出良好的性能,甲烷燃烧催化活性明显好于其他制备方法,起然温度和完全转化温度分别为387.2℃和592.7℃。采用非晶态合金法制备了LaSr_1-xCe_xFeCoO₆（x=0.5,0.1,0.2）和La_1-xCe_xSrFeCoO₆（x=0.05,0.1,0.2）系列双钙钛矿型复合氧化物,实验结果表明,在空气气氛下1100℃焙烧3h后,当稀土Ce掺杂量较小时（x=0.05）形成单一相物相,当掺杂量较大（x>0.05）时形成含少量CeO₂的混合相,CH₄活性评价表明掺杂Ce后催化剂的甲烷燃烧催化活性与Ce掺杂量成顺变关系。更多还原

【Abstract】 The double perovskite LaSrFeCoO₆ were synthesized by different methods and characterized by means of XRD, FT-TR, H₂-TPR, SEM, XPS , magnetic properties and activity of methane catalytic combustion.We found that the LaSrFeCoO₆ catalyst calcinated at 1100℃for 3h in air was single-phase double-perovskite which was synthesized by the sol-gel methode with citric acid, glucose and sucrose as complexing agent. It showed that the catalyst with citric acid as complexing agent had the best methane combustion activity .The results showed that T₁₀ （methane conversion of 10%） and T₉₀ （methane conversion of 90%） were 432.7℃and 639.2℃. The complex agent greatly affected the catalyst surface area and surface area is proportional to methane combustion activity . We compared chemical and physical properties of LaSrFeCoO₆ catalyst with citric acid as complexing agent which was calcinaed at different temperatures. The single-phase was formed at 500℃, which indicate that the sol-gel method could synthesize double perovskites in lower calcinate temperature. Calcination temperature greatly affected catalysts surface area. And apparent activation energy is also influence catalytic activity. We also synthesized double perovskite LaSrFeCoO₆ by amorphous alloy method, sol-gel method and microemulsion method. The single-phase double perovskite LaSrFeCoO₆ calcinated 1100℃for 3h in air was synthesized by all of the three methods. The catalyst synthesized by amorphous alloy method showed good hydrogen reduction ability, electric simulation surface density and apparent activation energy. It shows better catalytic activity for methane combustion, the result showed that T₁₀ was 387.2℃and T₉₀ was 592.7℃.The perovskite-type composite oxides LaSr_1-xCe_xFeCoO₆ （x=0.05, 0.1, 0.2） and La_1-xCe_xSrFeCoO₆ （x=0.05, 0.1, 0.2） were synthesized by amorphous alloy method. The result showed the catalyst calcinated at 1100℃for 3h in air formed a single-phase when Ce doped 0.05. When x>0.05, it could formed mixed phase with a little of CeO₂. According to the experiment results,we know that the methane combustion activity is proportional to the doping ratio of Ce.更多还原