Cu-ZSM-5的NH3选择性催化还原NO性能及其稳态动力学

采用浸渍法制备了一系列不同Cu载量的Cu-ZSM-5整体式催化剂.考察了该系列催化剂的NH3选择性催化还原(SCR)NO的反应特性.结果表明,当Cu质量分数为5%时,Cu-ZSM-5催化剂的SCR活性最高,此时催化剂上NO最高转化率高达96.5%,并且催化剂的活性窗口较宽,催化剂在198-470℃之间NO转化率大于80%.H2O和SO2的添加仅轻微影响Cu-ZSM-5催化剂的SCR活性.当Cu载量大于5%时,Cu-ZSM-5催化剂中出现明显的CuO物相.稳态动力学结果表明,在5%Cu载量的Cu-ZSM-5上的SCR反应中,NO的反应级数接近一级,NH3的反应级数接近零级,O2的反应级数接近1/2级.该反应的表观活化能为47.7kJ·mol-1.

Catalytic Performance and Steady-State Kinetics of Cu-ZSM-5 for Selective Catalytic Reduction of NO with NH3

A series of Cu-ZSM-5 catalysts with different Cu loadings were prepared by an incipient wetness impregnation method.These catalysts were used for studies of selective catalytic reduction(SCR)of NO by NH 3.The results showed that Cu-ZSM-5 with 5%Cu loading showed the best catalytic activity,the conversion of NO was more than 80%over the temperature range 198-470℃,and the highest NO conversion was 96.5%.The SCR activity was only influenced slightly by the addition of H 2 O or SO 2.Visible diffraction of the CuO phase was observed when the Cu content was above 5%.The results of steady-state kinetics studies indicated that the SCR reaction over Cu-ZSM-5 with 5%Cu loading was zero-order with respect to NH 3,first-order with respect to NO,and nearly half-order with respect to O 2.The apparent activation energy for the reaction was found to be 47.7 kJ·mol-1.