CuO/Ti_(0.5)Zr_(0.5)O_2催化剂上NO+CO反应活性的研究  

Studies of the Activities of CuO/Ti_(0.5)Zr_(0.5)O_2 Catalysts for NO+CO Reaction

作　　者：丁光辉[1] 蒋晓原[1] 林年达[1] 吴奔[1] 郑小明[1] 

机构地区：[1]浙江大学理学院化学系催化研究所,杭州310028

出　　处：《化学通报》2003年第10期673-677,共5页Chemistry

摘　　要：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。In this paper,the CuO/Ti 0.5Zr 0.5O 2 catalysts were prepared for the catalytic reduction of NO by CO.Its reducibility and thermal stabilities were examined by using a microreactor-Gc NO+CO reaction system, TPR, TG_DTA and NO_TPD methods.The results show that the Cu loading and calcination temperature have the effects on the catalytic activity.The NO conversion reaches 100% when the reaction temperature of 30% CuO/Ti 0.5Zr 0.5O 2 (500℃, 2h) is 400℃.TPR profiles indicate that there are two peaks(α,β) when the Cu loading less than or equal to 12%;whereas the catalyst with higher Cu loading display have another peak(γ) at about 300℃.The α peak is attributed to the reduction of high dispersed CuO species,the β peak is the reduction of isolated CuO species,the γ peak is the reduction of crystal CuO.TG_DTA curve shows that the exothermic peak appeared at about 725℃ is the completeness of crystalline ZrTiO\-4.The results of NO_TPD spectra indicate that NO on TZ appears two desorption peaks,while NO on 12%CuO/TZ catalysts calcined at 500℃ and 750℃ respectively appears three desorption peaks,it only appears two desorption peaks on catalysts calcined at 850℃ and 950℃.And the desorption peaks temperature of NO on the above catalysts at different calcination temperature is lower than that of carrier,which indicate that the decomposition activity of NO on the CuO/TZ catalyst is higher than that of on the Ti 0.5Zr 0.5O 2.

关 键 词：CuO/Ti0.5Zr0.5O2 催化剂 NO+CO反应 活性 浸渍法 复合氧化物 载体 

分 类 号：O643.32[理学—物理化学]