State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027, PR China.
J Hazard Mater. 2010 Feb 15;174(1-3):734-9. doi: 10.1016/j.jhazmat.2009.09.112. Epub 2009 Sep 24.
A series of Ce-Ti mixed-oxide catalysts were prepared by the sol-gel method for selective catalytic reduction (SCR) of NO with ammonia as reductant. These catalysts were characterized by XRD, BET, and XPS techniques. The experimental results show that the best Ce-Ti mixed-oxide catalyst yielded 98.6% NO conversion, and 100% N(2) selectivity at typical SCR reaction temperatures (300-400 degrees C) and the high gas hourly space velocity of 50,000 h(-1). As the Ce loading (the mass ratio of CeO(2)/TiO(2)) was increased from 0 to 0.6, NO conversion increased markedly, but decreased at higher Ce loading. The most active catalyst was obtained with a Ce loading of 0.6. The high activity might be attributed to high Ce loading, strong interaction between Ce and Ti, high concentration of amorphous Ce on the catalyst surface, or the increase of chemisorbed oxygen or/and weakly bonded oxygen species, resulting from the presence of Ce(3+) after Ce addition. The effect of the calcination temperature was also investigated, and the optimal calcination temperature was 500 degrees C. The presence of oxygen played an essential role in NO reduction, and the activity of the Ce(0.6)Ti catalyst was not depressed when oxygen concentration was higher than 1%. The effect of SO(2) and H(2)O on the activity of the Ce(0.6)Ti catalyst was bound up with the reaction temperature.
采用溶胶-凝胶法制备了一系列 Ce-Ti 复合氧化物催化剂，用于氨作为还原剂的选择性催化还原（SCR）NO。采用 XRD、BET 和 XPS 技术对这些催化剂进行了表征。实验结果表明，最佳 Ce-Ti 复合氧化物催化剂在典型的 SCR 反应温度（300-400°C）和高气体时空速度（50,000 h(-1)）下，NO 转化率达到 98.6%，N(2)选择性达到 100%。随着 Ce 负载量（CeO(2)/TiO(2)的质量比）从 0 增加到 0.6，NO 转化率显著增加，但在更高的 Ce 负载量下降低。Ce 负载量为 0.6 时，得到了最活跃的催化剂。高活性可能归因于高 Ce 负载量、Ce 和 Ti 之间的强相互作用、催化剂表面高浓度的无定形 Ce 或 Ce(3+)的存在导致化学吸附氧或/和弱键合氧物种的增加。还研究了煅烧温度的影响，最佳煅烧温度为 500°C。氧的存在对 NO 还原起着至关重要的作用，当氧浓度高于 1%时，Ce(0.6)Ti 催化剂的活性不会降低。SO(2)和 H(2)O 对 Ce(0.6)Ti 催化剂活性的影响与反应温度有关。
