纳米立方体核壳结构Fe基金属氧化物催化材料的构建及应用于中低温NH3选择性催化还原NO反应

Nitrogen oxides have been recognized as one of the main atmospheric pollutants. Low temperature smoke was discharged from industrial combustion equipment, which contained a large number of NOx. It is difficult to be eliminated by the available and conventional V2O5- WO3/ TiO2 catalyst. Obviously, the key lies in the research and development of eco-friendly SCR catalyst with high activity, H2O and SO2 durability at medium and low temperature. The project intends to synthesize a series of nano-cubic bimetallic Fe-PBA nanocrystals using the self-assembly methods. Moreover, the porous nano-cube Fe- based bimetal oxides were prepared by adjusting parameters of calcination. The internal structure of the porous nano-cube possessed fast charge transfer property, which can enhance the synergy among the active species, promote generation rate of chemisorbed oxygen and accelerate the fast SCR reaction at low temperature. Furthermore, Fe-PBA were uniformly covered by Me(OH)n shell with precipitation. Through this way, the core-shell nano-cube Fe-based metal oxides were constructed. The shell-core structure can not only protect the active components, but also improve the reaction activity, stability, H2O and SO2 tolerance at medium and low temperature SCR. These advantages are attributed to the stronger interaction between the shell and core. Through the systematic analysis of the association among of the catalytic materials microstructure– charge transfer property– strong interaction of core-shell structure– SCR catalytic performance at medium and low temperature. It could be established a mechanism on how charge transfer property and strong interaction of core-shell structure affect SCR performance, and provided a theoretical basis for the development of high-efficiency and stable Fe- base industrial catalysts.

氮氧化物是主要大气污染物之一，工业燃烧设备产生的低温烟气中含有大量的NOx，难以采用现有的常规V2O5-WO3/TiO2催化剂处理，亟需研发具备抗水、抗硫性能优良的中低温环保SCR脱硝催化剂。本项目拟采用“纳米粒子自组装模式”合成立方体型双金属Fe-PBA纳米晶体，调节焙烧工艺条件，制备多孔纳米立方体Fe基双金属氧化物。借助多孔纳米立方体结构中电荷快速传递作用，来增强活性物种之间的协同效应，促进化学吸附氧生成速率，从而提升中低温快速SCR反应效率。在Fe-PBA表面均匀沉淀Me(OH)n壳层，构建核壳结构纳米立方体Fe基多金属氧化物，利用壳层保护活性组分的同时，壳-核结构之间强的相互作用，可提高中低温SCR反应活性，稳定性和抗水、抗硫性能。系统分析催化材料微观结构—电荷传递作用—核-壳结构强相互作用—中低温SCR催化性能之间的构效关系，为后续研制高效稳定的Fe基工业脱硝催化剂提供理论依据。

石化燃料在工业燃烧过程中产生的大量的NO，排放温度较低（120-220℃），处理难度大。主要内容如下（1）借助PBAs材料结构制备系列Ce@Ce-Fe催化剂，壳层CeO2与Ce-Fe形成更强的相互作用，大幅度提高活性物种Ce3+、Oα含量，促进了低温SCR反应，提高催化材料抗中毒性能。（2）构筑系列MnFeOx催化材料，TiO2壳层显著增加催化剂表面的酸性位点；CeO2壳层有效增加催化剂表面氧空位缺陷位点，从而提高MnFe@CeOx催化剂的低温催化性能和抗水性能。（3）壳层间产生的界面扩散效应可以显著增强MnOx、FeOx、CeOx和TiOx之间的电子相互作用。在120-260℃脱硝率在90%以上。（4）通过原位红外探究双壳MnFe@CeOx@TiOx催化剂低温SCR反应遵循L-H机理。与催化剂生产企业开展了中低温脱硝关键技术与工业应用研究。本项目实施过程中，发表Chem. Eng. J.,ACS Appl. Nano Mater.等SCI论文15篇。申请发明专利9项，已授权发明专利3项。课题负责人张国栋助理研究员及赵海军副研究员获得多项相关课题资助。协助培养硕士研究生2名，博士研究生1名，其中毕业硕士研究生1名。