【作者】 马佳；

【导师】 龚彩荣；

【作者基本信息】 天津大学 ， 材料学， 2016， 硕士

【摘要】 碳烟颗粒物的排放是限制柴油机发展和应用的重要因素之一,也是空气污染的元凶之一。研究表明,铜催化剂表现出了良好对于碳烟颗粒物的催化活性,是未来取代贵金属催化剂的最有潜力的催化剂之一。同时,载体在铜催化剂中扮演着重要的角色,能够很大程度影响铜催化剂的催化活性。本文从铜催化剂的载体着手,使用XRD、SEM、TEM、ICP-MS、氮气吸附-脱附等温曲线、TPO、TPR等手段表征了载体和催化剂的物化性质和催化活性,首先比较了钙钛矿型载体BaTiO₃与三氧化二铝载体BaAl2O3对于铜催化剂的作用,然后制备了高比表面积的改性钙钛矿型载体Fe₃O₄@BaTiO₃,并且与钙钛矿型载体BaTiO₃对于铜催化剂的作用进行了比较,得到了以下结论:1.使用溶胶-凝胶的方法制备了钙钛矿型氧化物载体Ba TiO3,且为排除Ba-的干扰,制备了Ba-掺杂的三氧化二铝载体BaAl2O3,同时制备了两种载体担载的铜催化剂:Cu/BaTiO₃和Cu/BaAl2O3。2.比较了Cu/BaTiO₃和Cu/BaAl2O3两种铜催化剂对于碳烟颗粒物的催化活性,虽然两种载体没有表现出直接的催化活性,但是载体与铜之间的相互作用影响了铜催化剂的活性,在O₂氛围下Cu/BaTiO₃铜催化剂的特征温度Tm比Cu/BaAl2O3铜催化剂的Tm低32°C,在NOX/O₂氛围下Tm低41°C。并且,通过H2-TPR的测试,证实是由于载体-氧化铜之间的相互作用影响了铜的还原性。然而钙钛矿型载体的比表面积较小,只达到了9 m2/g,这是限制其作为金属氧化物催化剂载体的主要因素。3.采用包覆-水热-煅烧三步法制备了核壳结构的钙钛矿型纳米微球载体Fe₃O₄@Ba TiO3,载体的相对比表面积达到了44m2/g,远远高于钙钛矿型载体BaTiO₃。并且利用浸渍法制备了Cu/Fe₃O₄@BaTiO₃和Cu/BaTiO₃两种铜催化剂。4.比较了Cu/BaTiO₃和Cu/Fe₃O₄@BaTiO₃两种铜催化剂对于碳烟颗粒物的催化活性。在O₂氛围下,Cu/Fe₃O₄@BaTiO₃的特征温度Tm比Cu/BaTiO₃的Tm低32°C,在NOX/O₂氛围下低56°C。同样受到了载体-铜的相互作用,Fe₃O₄@Ba TiO3负载的氧化铜的还原能力进一步地提高了。更多还原

【Abstract】 Diesel particulate matter（PM,mainly containing soot）,undesired by-products of diesel engines in combustion process,have been recognized among the top threads to environment and human health which has driven research focusing on solutions.Copper catalyst has showed excellent catalytic activity,and is a potential substitution for noble metal.And support is an important factor on the catalytic activity of metal oxide catalysts.In this study,we focus on the supports of copper catalysts,the physic-chemical properties of supports and copper catalysts are characterized by XRD,SEM,TEM,ICP-MS,Raman,and N2-adsorption-desorption isotherm.The catalytic activity of copper catalysts for soot combustion were studied by TPO and H2-TPR.the effect of three kind of supports（Ba Al2O3,BaTiO₃ and Fe₃O₄@BaTiO₃）on soot combustion of cooper catalysts were also studied and the main conclusion are listed as followed:1.A stabilized alumina,containing Ba and a titanium-based mixed oxide,also containing Ba were prepared and used as copper supports.Denoted as Ba Al2O3,BaTiO₃,Cu/BaTiO₃ and Cu/Ba Al2O3.2.The catalytic activity of Cu/BaTiO₃ and Cu/Ba Al2O3 on soot combustion were compared,though the two supports could not contribute directly to catalytic activity of copper catalysts,for they have little catalytic activity,but they affect the catalytic activity of copper.Tm of Cu/BaTiO₃ is decreased by 32 °C and 41 °C compared with that of Cu/Ba Al2O3 under O₂ and O₂/NOX,respectively.the reduction temperature of Cu/Fe₃O₄@BaTiO₃（271 °C）is lower than that of Cu/BaTiO₃（305 °C）under H2,indicating copper is more easily reduced when supported on BaTiO₃.However,the BET surface area is only 9 m2/g which will restrict the development of metal oxides catalysts.3.Fe₃O₄@BaTiO₃ core/shell microspheres were synthesized by a hydrothermal-annealing approach.The specific surface area of Fe₃O₄@BaTiO₃ support is much larger（44 m2/g）than that of BaTiO₃ support.And two kinds of copper catalysts（Cu/Fe₃O₄@BaTiO₃ and Cu/BaTiO₃）were prepared.4.The catalytic activity of Cu/Fe₃O₄@BaTiO₃ and Cu/BaTiO₃ on soot combustion were compared,though the two supports could not contribute directly to catalytic activity of copper catalysts,for they have little catalytic activity,but they affect the catalytic activity of copper.Tm of Cu/Fe₃O₄@BaTiO₃ is decreased by 32 °C and 56 °C compared with that of Cu/BaTiO₃ under O₂ and O₂/NOX,respectively.The reduction temperature of Cu/Fe₃O₄@BaTiO₃（305 °C）is lower than that of Cu/BaTiO₃（388 °C）,indicating copper is more easily reduced when supported on Fe₃O₄@BaTiO₃ under H2.Fe₃O₄ has excellent catalytic activity for soot combustion,but covered by a BaTiO₃ layer,the ability of catalysis is feeble under O₂ gas flow.更多还原