Cu-Ce/ZSM-5催化剂的TPR及动力学研究

TEMPERATURE-PROGRAMMED REDUCTION AND KINETIC STUDIES ON CATALYSTS Cu-Ce/ZSM-5

由 Cu、Ce的硝酸盐 (氧化物 )用浸渍法、分散法制备了系列 Cu-Ce/ZSM-5催化剂。对这些催化剂进行了TPR、IR表征及动力学研究。考察了铜含量、铈含量及不同铈源对催化剂还原性能的影响。结果表明 :1 .不含铈的 Cu/ZSM-5催化剂的 TPR谱 ,铜离子的两个还原峰峰温及峰面积随铜含量增加而增加 ;2 .铈源为Ce O2 ,铈含量增大 ,使 Cu-Ce/ZSM-5催化剂的铜离子还原峰峰温略为降低 ;铈源为 Ce(NO3) 3· 6H2 O,铜离子还原峰峰温则随铈含量增加而升高 ;3 .计算了各催化剂铜离子还原反应的活化能 ,并确定还原反应为二级反应。 Ce O2 为铈源 ,活化能随铈含量增大而减小 ;Ce(NO3) 3· 6H2 O为铈源 ,活化能随铈含量增大而略为增加 ;4.催化剂的 IR谱对铜、铈含量不甚敏感 ,铈源对其影响相对较大。

The catalysts Cu Ce/ZSM 5 were prepared by the conventional impregnation method and dispersion method using CeO 2 or Ce(NO 3) 3·6H 2O as the cerium source.The catalysts were characterized by TPR and IR.Kinetic studies on these catalysts were also carried out.The results indicate the reduction reaction of copper ion to be a second order reaction.The TPR peak temperatures and the area of copper ion of the catalysts Cu/ZSM 5 were increased with the increasing of the copper content.Using CeO 2 as the cerium source,the TPR peak temperatures and the area of copper ion of the catalysts Cu Ce/ZSM 5 were decreased with the increasing of the copper content,but they increased slightly by using Ce(NO 3) 3·6H 2O.The IR spectra of the catalysts are not sensitive to the content of ions,but the cerium soureces have influence on the spectra.