Abstract: Sintering flue gas is faced with serious denitrification pressure, traditional vanadium tungsten titanium catalyst can effectively remove nitrogen oxides in industrial flue gas above 280℃, which is 100~150℃ higher than that of sintering flue gas. The purpose of denitrification can be achieved by heating sintering flue gas, but it will undoubtedly cause huge energy consumption, which is inconsistent with the concept of carbon emission reduction proposed by China. Therefore, it is necessary to develop denitrification catalysts with low-temperature activity. At present, the CeMn-based catalyst can achieve efficient denitrification in the sintering flue gas temperature range and has broad application prospects. In this study, the Ti/Sn doped CeMn composite metal oxide catalysts were prepared by a coprecipitation method. The effect of Ti/Sn modification on the denitrification and water resistance of the CeMnOx catalyst was studied. The microstructure, ammonia adsorption state, redox capacity, and surface element valence of CeMnOx catalyst were analyzed by physical and chemical properties characterization. The results showed that both Ti and Sn elements improve the low-temperature NOx conversion activity and water resistance of CeMnOx catalyst, and Ti presented a more significant improvement effect. At 150~250℃, the denitrification efficiency of CeMnTiOx was close to 100%. When the reaction temperature was 200℃ and the mixed gas contained 10vol% H2O, the denitrification efficiency of the catalyst remained above 95%. The results of H2 temperature programmed reduction, NH3 temperature programmed desorption, and X-ray photoelectron spectroscopy showed that the Ce-O-Ti and Mn-O-Ti structures in the modified catalyst improve the redox performance of the catalyst, increase the number of weak acid sites and medium strong acid sites on the surface of the catalyst, and form more oxygen vacancies, which made the catalyst exhibit better low-temperature activity.

Key words: sintering flue gas, low-temperature denitrification, CeMn-based catalyst, SCR, water tolerance

摘要： 采用共沉淀法制备了Ti/Sn掺杂的CeMn基复合金属氧化物催化剂，研究了Ti/Sn改性对CeMnOx催化剂的脱硝性能和抗水性能的影响，并通过物化性能表征对催化剂的微观结构、吸附氨状态、氧化还原能力以及表面元素价态进行了分析。结果表明，Ti和Sn元素的引入均可以提升CeMnOx催化剂低温NOx转化活性和抗水性能，并且Ti的提升效果更加显著，在150~250℃，CeMnTiOx脱硝效率接近100%，在200℃、10vol% H2O条件下，脱硝效率维持在95%以上。H2程序升温还原、NH3程序升温脱附及X射线光电子能谱等检测结果表明催化剂表面Ce-O-Ti和Mn-O-Ti结构的形成提升了催化剂的氧化还原性能，增多了催化剂表面弱酸位、中强酸位数量，同时形成了更多的氧空位，从而使催化剂获得了良好的低温NOx转化活性。

关键词: 烧结烟气, 低温脱硝, CeMn基催化剂, 选择性催化还原, 抗水