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以Ti0 5Zr0 5O2 复合氧化物为载体 ,采用浸渍法制备了不同负载量的CuO Ti0 5Zr0 5O2 (TZ)催化剂 ,考察了催化剂对NO的反应活性 ,并用TPR、TG DTA和NO TPD等技术对催化剂进行了表征。结果表明 ,CuO的负载量和焙烧温度对催化剂的活性均有影响。 30 %CuO Ti0 5Zr0 5O2 (5 0 0℃ ,2h)在反应温度为4 0 0℃时NO转化率为 1 0 0 %。TPR结果表明 ,CuO负载量≤ 1 2 %时 ,在TPR上出现了 2个还原峰 (即α和 β峰 ) ;而进一步提高CuO的负载量 ,出现了γ还原峰 ,推测α峰为高度分散Cu物种的还原 ,β峰为孤立的Cu物种的还原 ,γ峰则为晶相CuO的还原峰。TG DTA图谱显示在 72 5℃左右的放热峰是ZrTiO4 晶化过程的完成。NO_TPD结果表明NO吸附在TZ上的热脱附过程中 ,出现 2个脱附峰 ;而NO吸附在 1 2 %CuO TZ上 ,5 0 0℃和 75 0℃焙烧的催化剂上出现 3个脱附峰 ;而在 85 0℃和 95 0℃焙烧的催化剂上只出现 2个脱附峰 ,且NO在上述不同焙烧温度的催化剂上的脱附峰温均低于载体 ,这表明NO吸附在CuO TZ催化剂上比吸附在Ti0 5Zr0 5O2 上更容易脱出和分解。
CuO Ti0 5Zr0 5O2 (TZ) catalysts with different loadings were prepared by impregnation method with Ti0 5Zr0 5O2 composite oxide as support. The catalytic activity of the catalyst for NO was investigated. The catalysts were characterized by TPR, TG DTA and NO TPD Characterization. The results show that the loading of CuO and the calcination temperature have an impact on the activity of the catalyst. 30% CuO Ti0 5Zr0 5O2 (500 ℃, 2h) The NO conversion was 100% when the reaction temperature was 400 ℃. The results of TPR show that there are two reduction peaks (ie, α and β peaks) on the TPR when the CuO loading is less than 12%, while the γ reduction peak appears further on the loading of CuO. The α peak is presumed to be highly dispersed Cu species reduction, β peak is isolated Cu species reduction, γ peak is the reduction phase of crystalline phase CuO. The TG DTA pattern shows that the exothermic peak around 72 5 ° C is the completion of the crystallization of ZrTiO4. The results of NO_TPD showed that there were two desorption peaks during the thermal desorption of NO adsorbed on TZ, whereas NO adsorbed on 12% CuO TZ showed three desorptions on the catalyst calcined at 500 ℃ and 75 ℃ Peak. However, only two desorption peaks appear on the catalyst calcined at 85 0 ℃ and 95 0 ℃, and the desorption peak temperatures of NO on the catalysts with different calcination temperature are lower than that of the support, indicating that NO is adsorbed on CuO TZ On the catalyst adsorbed on the Ti0 5Zr0 5O2 easier prolapse and decomposition.