VmTi和KnV0.04Ti担载氧化物催化剂的表征与催化燃烧柴油炭黑的性能

用FTIR和UV-Vis研究了2个系列不同V和K负载量的VOx/TiO2和K-VOx/TiO2催化剂结构的变化;并使用程序升温氧化反应技术对这两种催化剂催化柴油炭黑燃烧活性进行了考察.结果表明,当VOx/TiO2催化剂中n(V)∶n(Ti)=0.04时,催化剂活性最好(tm=389℃).添加K能显著改善VOx/TiO2催化剂活性,n(K)∶n(V)∶n(Ti)=0.04∶0.04∶1时,炭黑燃烧的反应温度最低(tm=343℃).FTIR和UV-Vis结果表明,当VOx/TiO2催化剂n(V)∶n(Ti)>0.04∶1时,催化剂表面有V2O5形成,由于V2O5氧化能力较弱,因而催化剂的活性反而降低.而当K-VOx/TiO2催化剂中n(K)∶n(V)达到1∶1时,由于形成的KVO3物种与TiO2载体有很好的协同作用,所以催化剂活性最好.

Characterization of VmTi and KnV0.04Ti Catalysts Supported by Oxide and Their Catalytic Performances for Diesel Soot Combustion

Two systems of VmTi and KnV0.04Ti catalysts were prepared by incipient-wet impregnation method and their catalytic performances for diesel soot combustion were investigated by using temperature-programmed oxidation(TPO) reaction. The results show that the V0.04Ti catalyst has a good activity for diesel soot combustion(tm=389 ℃). The addition of potassium to VOx/ TiO2 catalysts can apparently improve their catalytic activities for soot oxdation. And when n(K)∶n(V)∶n(Ti)=(0.04∶0.04∶1,) the catalysis activity is the best, and the temperature of soot combustion reaction is the lowest reaction temperature(tm=343 ℃). The structural characterization results by FTIR and UV-Vis reveal that V2O5 formed on the surfaces of the VmTi catalysts when m exceeded 0.04. The (K0.04V0.04Ti) catalyst has a highest catalytic activity. It is due to the formation of KVO3 which has a good synergetic effect with TiO2 support in the catalyst.