Zr的添加对提高NH_3选择性催化还原NO_x整体式催化剂热稳定性的影响（英文）  

Promotional Effect of Zr on Thermal Stability of CeTiO_x Monolith Catalyst for Selective Catalytic Reduction of NO_x with Ammonia

作　　者：徐宝强[1] 徐海迪[2,3] 曹毅[1] 兰丽[1] 杨怡[1] 张艳华[1] 李元山[4] 龚茂初[1] 陈耀强[1,3] 

机构地区：[1]四川大学绿色化学与技术教育部重点实验室,成都610064 [2]四川大学新能源与低碳技术研究院,成都610064 [3]四川省环境保护环境催化材料工程技术中心,成都610064 [4]四川大学化学工程学院,成都610064

出　　处：《无机化学学报》2016年第3期517-526,共10页Chinese Journal of Inorganic Chemistry

基　　金：四川省科技厅科技支撑项目(No.2012FZ0008);国家自然科学基金(No.21173153);国家高技术研究发展计划项目(863)(No.2013AA065304);四川大学项目(No.2015SCU11056)资助

摘　　要：采用共沉淀的方法制备了Ce Ti O_x和Ce Zr Ti O_x两种用于NH_3选择性催化还原NO_x的催化剂。两种催化剂在不同的高温条件下进行热老化以考察Zr的添加对Ce Ti O_x催化剂热稳定性的影响。NH_3-SCR活性数据显示,经过650、750和850℃的高温老化处理,Zr改性后的催化剂较Ce Ti O_x催化剂具有更好的催化活性和N2选择性。XRD、Raman和H_2-TPR结果表明添加Zr可以阻止Ce物种的烧结并且抑制金红石相Ti O_2的生成。催化剂的SEM图像显示Zr的添加可以抑制颗粒随着焙烧温度升高而产生的聚集长大。XPS的Ce3d光谱表明,随着老化温度的提升,Ce Ti O_x催化剂表面的Ce^(3+)/Ce4+比相对于Ce Zr Ti O_x催化剂下降更加明显。这意味着随着Zr的添加,更多的晶格缺陷和氧空缺出现在Zr改性催化剂的表面,这有利于催化性能的提升。另外,NH_3-TPD结果表明经过相同的高温老化,改性的催化剂保持了更多的Br觟nsted酸性位,提高了催化活性并抑制了氨的氧化。因此,Zr的添加提高了催化剂的热稳定性能。CeTiOxand CeZrTiOxcatalysts were prepared by co-precipitation method and used for selective catalytic reduction of NOxby NH3（NH3-SCR）. Thermal aging of the two catalysts was conducted at various temperatures to investigate the effect of Zr on thermal stability of Ce Ti Oxcatalyst. The NH3-SCR performance of the catalysts showed that the Zr-modified catalyst exhibited better activity and N2 selectivity than Ce Ti Oxcatalyst after high temperature aging at 650, 750 and 850 ℃. The XRD, Raman and H2-TPR results illustrated that the addition of Zr could prevent Ce species from sintering and inhibit the formation of rutile Ti O2. The SEM images of the catalysts revealed that the aggregation of the particles with increasing calcination temperature could be inhibited by addition of Zr. From the XPS spectra of Ce3 d, the ratio of Ce^3＋/Ce^4＋ of Ce Ti Oxdecreased more sharply than that of Ce Zr Ti Oxwith the aging temperature, meaning that more crystal defects and oxygen vacancies were preserved after Zr addition, which led to increased catalytic performance. In addition, NH3-TPD results implied that modified catalyst possessed larger amounts of Brnsted acid sites after calcining at a same temperature, improving the activity and inhibiting the NH3 oxidation. Thus, a conclusion could be drawn that Zr addition improved the thermal stability of the Ce Ti Oxcatalyst.

关 键 词：铈钛复合氧化物 锆 热稳定性 选择性催化还原 NOx 

分 类 号：O613.61[理学—无机化学]