VO_x/ZrO_2和K-VO_x/ZrO_2催化剂的结构与催化碳黑氧化性能  

The Structures of VO_x/ZrO_2 and K-VO_x/ZrO_2 Catalysts and Their Catalytic Perfo rmances for Diesel Soot Oxidation

作　　者：刘坚[1] 赵震[1] 徐春明[1] 

机构地区：[1]石油大学重质油国家重点实验室,北京102249

出　　处：《物理化学学报》2005年第2期156-160,共5页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(20473053);教育部留学回国人员科研启动基金资助项目~~

摘　　要：采用等体积浸渍法制备两个系列不同V和K负载量的VOx/ZrO2和K-VOx/ZrO2催化剂.利用程序升温氧化反应(TPO)技术对VOx/ZrO2和K-VOx/ZrO2催化碳黑氧化的活性进行了考察.实验结果表明,当催化剂中V的负载量nV/nZr=4/100时,VOx/ZrO2催化剂的活性最好.添加K能显著改善VOx/ZrO2催化剂的活性,当K的添加量为nK∶nV∶nZr=1∶4∶100时,碳黑氧化的反应温度最低.催化剂的红外光谱和紫外-可见光谱表征的结果表明,nV/nZr=4/100时,催化剂的表面形成聚合的V物种浓度最大.由于聚合的V物种具有较强的氧化还原能力,因而能显著地降低柴油碳黑的氧化温度.当K-VOx/ZrO2催化剂中nK/nV超过1/4时,由于形成KVO3物种,催化剂表面原子的移动性减弱,因而催化活性降低.Two systems of VOx/ZrO2 and K-VOx/ ZrO2 catalysts with different compositions were prepared by incipient-wetness impregnation method. The catalytic performances of these catalysts for diesel soot catalytic oxidation were investigated with temperature-programmed oxidation reaction(TPO). The results showed that the catalytic properties of the VOx/ZrO2 catalysts depend on the VOx concentration. The VOx/ZrO2 catalyst has the best activity for soot oxidation when n(V): n(Zr) is 4: 100. The VOx/ZrO2 and K-VOx/ZrO2 catalysts were characterized by FT-IR and UV-Vis. The results revealed that the highest concentration of polymerized vanadyl species presented on the surfaces of the VOx/ZrO2 catalysts when n(V): n(Zr) = 4: 100. The polymerized vanadyl can lower the oxidation temperature of diesel soot because they have very strong redox abilities. The addition of potassium to VOx/ ZrO2 catalysts can improve the catalytic activities for soot oxidation apparently. When n(K): n(V): n(Zr) = 1: 4: 100, the catalyst K-VOx/ZrO2 has the best activity for soot oxidation, i.e., the lowest reaction temperature. But the catalytic activity of the K-VOx/ ZrO2 catalysts decreased when n(K): n(V) > 1: 4, which is due to the formation of KVO3 whose surface atoms mobility is much weaker than that of polymeric VOx specie and dispersed potassium oxide.

关 键 词：钒氧化物 二氧化锆 催化剂 碳黑 催化氧化 

分 类 号：X701.3[环境科学与工程—环境工程]