摘要
采用柠檬酸络合燃烧法制备了LaBO3(B=V,Cr,Mn,Fe,Co,Ni,Cu)复合氧化物.采用X射线衍射、紫外-可见漫反射光谱、傅里叶变换红外吸收光谱、氢程序升温还原及扫描电镜等手段对催化剂进行了表征,并对其在同时消除柴油机尾气中炭颗粒和NO反应中的催化活性进行了评价.结果表明,在制备的七种复合氧化物中,除La-V-O和La-Cu-O外,均形成钙钛矿结构.LaBO3钙钛矿型氧化物氧化能力由强到弱的顺序为LaCoO3≈LaNiO3>LaMnO3>LaFeO3>LaCrO3,在同时消除炭颗粒和NO的催化反应中,钙钛矿复合氧化物催化剂的催化活性与其氧化能力直接相关.其中LaCoO3和LaNiO3样品对炭颗粒的氧化催化活性较好,在炭颗粒与催化剂松散接触的条件下,炭颗粒燃烧温度较低,分别为421和431℃,生成CO2的最大选择性高,分别为99.1%和99.7%,NO生成N2的转化率分别为17.2%和20.1%.
The nanometric LaBO3（B=V, Cr, Mn, Fe, Co, Ni, Cu）oxides were prepared by the organic acid ligation method. The samples were characterized by the techniques of XRD, UV-Vis, FT-IR, H2-TPR, and SEM. The catalytic performance of the prepared samples for the simultaneous removal of soot and NO emitted from diesel engines was investigated. The results showed that the synthesized LaBO3 （B = Cr, Mn, Fe, Co, Ni） oxides possess perovskite-type structures except for La-Cu-O and La-V-O. The oxidizing ability of these five perovskite oxides follows the order of LaNiO3 ≈ LaCoO3 〉 LaMnO3 〉 LaFeO3 〉 LaCrO3, which is consistent with their activity sequence for the desired reactions. Thus their catalytic performance is closely related to the oxidizing ability of these perovskite oxides. Among them, LaCoO3 and LaNiO3 have higher activities for the simultaneous removal of soot and NO. The combustion temperatures （Tm） of soot particles over them are 421 and 431 ℃, respectively, when the contact between catalysts and soot are loose. The selectivities of CO2 are 99.1% and 99.7% , and NO conversions are 17.2% and 20.1%, respectively.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2008年第7期649-654,共6页
基金
国家自然科学基金(20473053
20773163)
北京市自然科学基金(2062020)
