摘要
选用醋酸锰作为成壳的前驱物质、纳米二氧化硅作为核材料,分别采用浸渍法、浸渍沉积法和层层自组装法制备SiO2/MnOx核壳结构催化剂,并探索所制核壳结构催化剂NO低温催化氧化活性,对3种方法所制催化剂进行TEM表征。此外,分别研究核壳结构催化剂制备过程中核材料SiO2焙烧温度、SiO2负载锰物质后的焙烧温度、焙烧时间和锰负载量（质量分数）4个因素对催化剂催化性能的影响。研究结果表明：层层自组装法可制备出核壳结构催化剂,SiO2球形颗粒表面形成了厚度均一、包裹完整、界面清晰的晶状物壳层,壳层厚度为6-15 nm;能量色散谱仪（EDS）结果显示壳层上包覆物质主要为MnOx晶粒。在SiO2焙烧温度为400℃,SiO2负载锰物质后的焙烧温度为400℃,焙烧时间为4 h,锰负载量为15%条件下制得的SiO2/MnOx核壳结构催化剂,在反应温度为150℃时,NO转化率可达38.3%（进口配气为0.05%NO和3%O2（体积分数）,空速为30 000-35 000 h-1）,已达到现阶段较成熟的负载型锰基催化剂在此温度区间的NO转化水平。
To explore the catalystic properties of core-shell structure catalysts at low temperature NO catalytic oxidation, SiO2/MnOx core-shell structure catalysts were prepared using impregnation method, impregnation deposition method and layer-by-layer self-assembly method, respectively. SiO2 nanoparticles were used as the core and acetate manganese as the precursor of the shell. SiO2 nanoparticles and SiO2/MnOx core-shell structure catalysts were characterized by transmission electron microscopy （TEM） and energy dispersive spectrometer （EDS）. In addition, the calcination temperature of SiO2, the calcination temperature of SiO2/MnOx , the calcination time of SiO2/MnOx and Mn loadings （mass fraction） were considered. The results show that the spherical SiO2 is coated by MnOx, the core-shell surface is uniform and has clear interface, and the thickness of shell is about 6-15 nm. When the calcination temperature of SiO2 is 400 ℃, the calcination temperature of SiO2/MnOx is 400 ℃, the cacination time is 4 h and Mn loading is 15%, respectively, the NO conversion is about 38.3% at 150℃ with a space velocity of 30 000-35 000 h^-1 , and it achieves a similar level to some ripe supported manganese-based catalysts currently in the same temperature range.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2014年第1期328-333,共6页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(20907018)
关键词
核壳结构催化剂
层层自组装法
低温催化氧化NO
core-shell structure catalysts
layer-by-layer self-assembly method
NO catalytic oxidation at low temperatures
