【作者】 常雪；

【导师】 董国君；

【作者基本信息】 哈尔滨工程大学 ， 应用化学， 2009， 硕士

【摘要】 本文以堇青石蜂窝陶瓷为载体,采用铝、硅铝(SA)、钛铝(TA)复合溶胶对载体进行表面改性后,以铜锰复合金属氧化物(Cu-Mn-O)为活性组分制备催化剂。实验选择尿素作为还原剂,采用程序升温法,利用固定床流动化反应评价系统评价各催化剂选择催化还原NOx的催化活性。结果表明,复合溶胶改性有助于载体比表面积的提高。TA和SA复合溶胶改性后载体比表面积分别可达到54.64m2/g和70.25m2/g,与改性前相比,比表面积分别提高了67和86倍,催化剂在中低温的活性明显提高。实验对不同溶胶改性后催化剂的活性进行比较。研究发现,复合溶胶改性可以有效的提高催化剂对NOx的催化活性。TA复合溶胶改性后的催化剂对NOx的催化活性比A12O3、SA复合溶胶改性的催化剂活性要好。以催化剂活性为基础,实验确定Cu-Mn-O/TA2/CC为课题深入研究的方向。采用浸渍法制备了Cu-Mn-O/TA2/CC催化剂,考察了负载量、活性组分不同配比和焙烧温度对催化剂活性的影响。结果表明当Cu-Mn-O总负载量为9wt%,活性组分的配比为Cu:Mn=1:1,焙烧温度为500℃时,催化剂活性最高：在200℃时NOx的转化率达到最高为85%,并在150-350℃温度范围内均可以保持80%左右。运用X射线衍射技术(XRD)、比表面测定仪(BET)和扫描电子显微镜(SEM)、X射线光电子能谱分析(XPS)等方法对所制备的催化剂进行晶相结构、比表面积、表面形貌、表面元素价态的测试,结果发现：Cu-Mn-O/TA2/CC催化剂的比表面积在20-30m2/g之间,活性组分Cu物种以CuO和Cu2O两种形式存在,Mn以MnO2和Mn2O3形式存在,并且催化剂表面有CuMn2O4尖晶石生成,有利于活性组分Cu和Mn之间的电子传递,促进了NOx转化率的提高。更多还原

【Abstract】 In this thesis, a series of ceramic cordierite honeycomb modified by Al2O3, SiO2-Al2O3(SA) and TiO2-Al2O3(TA) composite sols, catalysts supported Cu-Mn-0 were studied for the SCR of NOx with CO(NH2)2. Catalytic activity tests were performed in a fixed-bed fluxion reactor with programmed temperature. The results showed that composite sols used in the process of catalysts modification are benefit to the surface areas. After modifying by TA and SA composite sols, the surface area of carrier was 54.64 and 70.25m2/g about 67 and 86 times lager than the former blank cordierite, respectively. The activity test indicated that modified by composite sols is benefit to extend the temperature range of catalyst in reduction NOx,.and the catalytic activity is improved due to the increasing of surface area of the carriers.Experiments of activity appraisal suggested that Cu-M-0 catalysts which modified by composite sols have good activity of DeNOx, and the activities of Cu-Mn-O/TA/CC were better than Cu-Mn-O/SA/CC and Cu-Mn-O/Al2O3/CC catalysts. Considering the activities of DeNOx, Cu-Mn-O/TA/CC were chosed for deep study.Cu-Mn-O/TA2/CC catalysts were prepared by impregnation method and applied for the removal of NOx by SCR. Effects of Cu-Mn-0 mixed oxides loading, Cu/Mn molar ratio and calcined temperature on NOx conversions were investigated. It is found that with the loading of 9wt%, Cu5-Mn5-O/TA2/CC calcined at 500℃is much more active than the catalysts:the highest activity is 85% at 200℃, and the NOx conversion holding about 80% during 150 to 350℃. The catalysts have been characterized by XRD、BET、SEM and XPS. The analysis revealed that the surface areas of Cu-Mn-0 catalysts modified by TA2 were between 20 and 30m2/g. The XPS of Cu5-Mn5-O/TA2/CC shows Cu species exist in the form of CuO and Cu2O, Mn species exist in the form of MnO2、Mn2O3 and CuMn2O4. The higher activity of Cu5-Mn5-O/TA2/CC catalyst has been ascribed to the formation of the copper manganese spinel CuMn2O4, precisely to an electronic transfer between copper and manganese cations within the spinel lattice.更多还原