K/CeO2催化剂上碳黑催化燃烧性能及稳定性（英文）

采用不同的钾盐前体制备了一系列K/CeO2催化剂,利用热重和程序升温氧化(TPO)等技术考察了其催化性能及稳定性.结果表明,K/CeO2催化剂可使碳黑完全燃烧温度降低近200oC.钾盐前体对催化活性和稳定性具有较大影响,由于硝酸钾熔点低,金属在载体上的流动性强,有利于催化剂与碳黑的有效接触,因而表现了较高的活性,三次TPO循环试验中催化活性稳定.碳酸钾的熔点高且碱性较强,使碳黑燃烧生成的CO2不可逆吸附在其表面,导致反应活性低,TPO循环实验表明其反应速率降低,失活明显.

Catalytic Activity and Stability of K/CeO2 Catalysts for Diesel Soot Oxidation

A series of CeO2 supported potassium nitrate and carbonate catalysts were prepared by an impregnation method.The catalytic activity and stability for soot oxidation were investigated by thermal gravimetric/differential thermal analysis and temperature-programmed oxidation cycle techniques.K/CeO2 substantially promotes the catalytic activity,which can be gauged by the lowering of the soot total removal temperature by more than 200 ℃ compared with the uncatalyzed reaction.The influence of K precursor on the catalytic activity and stability was addressed.The effect is discussed in terms of the combined functions of K and CeO2,potassium mobility and basicity.For po-tassium-promoted ceria catalysts the potassium nitrate can preserve the high catalytic activity and good stability through several cycles.When K was present as K2CO3,the activity and stability of catalyst were lower than those of KNO3/CeO2.This behavior is attributed to the higher melting point and stronger basicity of K2CO3 which lead to irreversible adsorption of CO2 generated during soot combustion on the catalyst.