CeMn氧化物催化剂的制备及其对甲苯的催化降解性能

采用草酸沉淀法合成了铈锰 氧化物（CeMn氧化物）催化剂,在固定床反应器中考察了不同Ce-Mn摩尔比、空速对CeMn 氧化物催化剂催化降解甲苯效果的影响,通过XRD、SEM、XPS等技术表征了催化剂的理化性质。实验结果表明：当n（Ce）∶n（Mn）=1∶3时得到的Ce₁Mn₃催化剂降解甲苯的活性最佳,T₅₀=198 ℃,T₉₀=249 ℃,且Ce₁Mn₃催化剂具有较好的活性稳定性;随着空速的增加,Ce₁Mn₃催化降解甲苯的性能变差。表征结果表明：CeMn氧化物形成的Ce-Mn固溶体使CeMn氧化物表面氧空位浓度增加,加快了氧物种在催化剂内部及表面的流动传输;Ce氧化物与Mn氧化物之间的协同作用使催化剂的还原峰向低温方向偏移,CeMn氧化物展现出更优异的低温活性。

Preparation of cerium-manganese oxide catalysts and their catalytic activities to toluene degradation

The cerium-manganese oxidecatalysts （CeMn oxides）were synthesized byoxalic acid precipitation method. The effects of mole ratio of cerium to manganese and airspeed oncatalytic degradation of toluene were investigated in a fixed bed reactor. The physical and chemical properties of CeMn oxides were characterized by XRD,SEM and XPS. The experimental results show that：The catalytic activity of Ce₁Mn₃ with n（Ce）∶n（Mn）=1∶3 for toluene degradation is the highest,where in T₅₀=199 ℃ and T₉₀=249 ℃,and has good stability;With the increase of airspeed,the catalytic activity of Ce₁Mn₃ to toluene degradation decreased. The characterization results indicate that：The concentration of oxygen vacancy on the surface of CeMn oxidesis increased with the Ce-Mn solid solution formed from CeMn oxides,so that the flow transmission of oxygen species inside and on the surface of the catalystis accelerated;The reduction peak of the catalyst shifts to the low temperature direction under synergy of Ce oxide and Mn oxide,and the low temperature activity of CeMn oxides is more excellent.