Ce掺杂改性Ni-Al-Ox催化剂CO-NO反应性能

通过尿素法制备了一系列Ce掺杂改性的Ni-Al-O_x复合氧化物催化剂，并研究了催化剂的CO-NO反应性能.活性测试结果表明，Ni-Al-Ce-O_x的催化活性明显优于Ni-Al-O_x，且活性随着Ce含量的增加而提高.当Ce的掺杂量为20%时，250℃条件下，NO转化率高达95%以上，同时催化剂具有良好的抗H₂O性能.XRD和Raman分析表明，Ce掺杂Ni-Al-O_x催化剂促进了氧空位产生.而XPS结果显示，氧空位随着Ce含量的增加而增加.H₂-TPR结果表明，Ce的掺杂使催化剂的氧化还原性能增强.结合NO-TPD和FTIR的表征结果，进一步发现Ce的加入使表面氧难以将NO氧化成硝酸盐，有利于NO在Ce的氧空位上分解为N₂或N₂O，促进CO-NO反应的进行.

Study on Ce-doped Ni-Al-Ox catalysts for NO reduction by CO

A series of Ce-doped Ni-Al-O_x catalysts were prepared by a urea-hydrolysis method, and were applied for CO-NO reaction. The results showed that Ce-doped Ni-Al-O_x exhibited much higher NO conversions than Ni-Al-O_x. Furthermore, the activity increased with the raising of Ce doping ratio. More than 95% NO could be converted at temperature as low as 250℃ over NiAlCe₃₀O and NiAlCe₂₀O. These catalysts also showed excellent resistance to H₂O. Ce-doped Ni-Al-O_x catalysts were characterized by XRD, N₂ physisorption, Raman, XPS, H₂-TPR, NO-TPD, and in situ DRIFTs. XRD and Raman results showed that Ni-Ce-O solid solution was formed in Ni-Al-Ce-O_xcatalyst. Meanwhile, oxygen vacancies increased with the increasing of Ce doping ratio. H₂-TPR results indicated that the redox ability was improved by Ce doping. NO-TPD and in situ DRIFTs results revealed that the increasing number of oxygen vacancies resulted from Ce doping were beneficial to the dissociation of NO to N₂ or N₂O rather than the oxidation of NO to nitrates.