Co/Mg/Al复合氧化物的制备与催化性能研究

The Preparation and Catalysis Research of Co/Mg/Al Composite Oxide

分别采用共沉淀和水热法制备了一系列不同金属配比的Co/Mg/Al水滑石前驱体,经高温焙烧得到了Co/Mg/Al纳米复合氧化物,采用XRD和FTIR对其结构进行了表征.结果表明：Co/Mg/Al水滑石前驱体样品具有典型的水滑石层状结构,焙烧后得到了CoAl2O4尖晶石相和MgO相.采用氮氧化物分析仪评价了其同时去除NOx和PM的催化活性.结果表明：反应温度和合成方法对NO转化率影响不大,Co/Mg/Al-LDO纳米催化剂在200～450℃的范围内均表现出较稳定的催化活性,在反应20 min后,NO的转化率趋于稳定.对于不同金属配比的催化剂,NO的转化率顺序为：Mg2Al1-LDO＞ Co1Mg1Al1-LDO＞ Co2Al1-LDO,NO的转化率分别约为71.5％,44.5％和34.5％.

A series of Co/Mg/AI hydrotalcites with different metal molar ratios were prepared by co-precipitation and hydrothermal method, respectively. Their structure was characterized by XRD and FTIR. The results show that Co/Mg/AI hydrotalcites have typical hydrotalcite structure. COAl2O4 spinel and MgO phase was obtained after calcinations. Their catalytic behavior on removal of NOx and PM was investigated by NOx analyzer. The results show that Co/Mg/AI composite oxide catalysts have stable catalytic activities during the temperature of 200-450 ℃. NO conversion becomes stable alter 20 min. The order of conversion of NO is Mg2AII-LDO〉Co1Mg1Al1-LDO〉Co2Al1-LDO, with the NO conversion of 71.5 %, 44.5 % and 34.5 %, respectively.